This automatic EPA certification will avoid unnecessary economic impacts on those manufacturers over 90 percent are small businesses who can then focus their efforts on developing a full range of cleaner models that meet Step 2 emission levels. We are promulgating a stepped compliance approach that will apply to all new central heaters. For hydronic heaters, standards will apply to each hydronic heater manufactured after May 15, and each hydronic heater sold after December 31, Step 1 p. Step 2 p. For hydronic heaters, we are not promulgating the alternative three-step emission limit approach for which we requested comment in the proposal.
For forced-air furnaces, standards will apply to each forced-air furnace manufactured or sold after May 15, Work practice and operational standards will apply to each forced-air furnace manufactured or sold at retail after May 15, Step 2 PM emission limits will apply to each forced-air furnace manufactured or sold at retail on or after May 15, For forced-air furnaces, we are not promulgating the alternative three-step emission limit approach for which we requested comment in the proposal.
However, commenters were very concerned about the infeasibility of enforcing an emission limits for forced-air furnaces due to the technical and economic impracticability of testing and certifying approximately 50 forced-air furnaces in the 60 days between publication of this rule and the effective date. For example, a typical forced-air Start Printed Page furnace certification test takes approximately 1 week in the laboratory after the furnace is shipped to the laboratory and a time is scheduled to begin testing.
Typically, the laboratory takes approximately 3 or 4 weeks to prepare a complete test report for the manufacturer to submit to the EPA. A reasonable overall estimate is approximately 1. Currently, there are only 4 laboratories that can test forced-air furnaces. We estimate that approximately 12 small forced-air furnaces and 38 large forced-air furnaces would need to be tested as soon as possible. If those tests were to be divided equally among the 4 laboratories, it would take a minimum of approximately 4 months to submit the 12 certification test reports for the small furnaces and an additional year to submit the 38 certification test reports for the large furnaces to the EPA, far longer than the 60 days between the publication date and the effective date.
Thus, as noted above, we are requiring work practice and operational standards on the effective date as allowed under section h 2 B of the CAA, and requiring Step 1 PM emission limits for small forced-air furnaces 1 year after the effective date and Step 1 PM emission limits for large forced-air furnaces 2 years after the effective date. The following are excerpts of the operational standards required in this rule that must be included in the owner's manuals. Operators must not burn unseasoned wood. The use of properly split, stored and seasoned wood has much lower PM emission than high-moisture wood, i.
Operators must not burn improper fuels such as 1 residential or commercial garbage; 2 lawn clippings or yard waste; 3 materials containing rubber, including tires; 4 materials containing plastic; 5 waste petroleum products, paints or paint thinners, or asphalt products; 6 materials containing asbestos; 7 construction or demolition debris; and 8 paper products; cardboard, plywood or particleboard Note that best practices do allow the use of fire starters made from paper, cardboard, saw dust, wax and similar substances for the purpose of starting a fire in an affected heater ; 9 railroad ties or pressure treated lumber; 10 manure or animal remains; 11 salt water driftwood or other or other previously salt water saturated materials; 12 unseasoned wood; and 13 any materials that are not included in the warranty and owner's manual for the subject heater or furnace.
The owner's manual and training materials must also educate operators on the use of proper operating practices, including correct positioning of bypasses and air dampers during startup, normal operation and reloading. Proper practices also include checking air tubes, catalysts if so equipped , heat exchangers and other critical parts of the heater to ensure they are working properly and are maintained as needed. Numerous comments noted that best work practices and proper operation and maintenance can significantly reduce emissions at reasonable costs.
Thus, considering all of the above, the EPA has determined that these work practice and operational standards represent the best systems of emission reduction as required by section h 1 for the immediate time frame from the effective date until the Step 1 PM emissions limits apply.
More discussion of comments on stepped compliance and the EPA's responses are in section V. Summary of Major Comments and Responses. Table 4 summarizes the PM emissions limits for hydronic heaters and forced-air furnaces that will apply at each step. We are allowing an alternative compliance option for manufacturers who choose to certify using cord wood rather than crib wood to meet the Step 2 limits for hydronic heaters. Numerous hydronic heater manufacturers may not be ready by the Step 2 compliance date and that could result in unreasonable economic impacts.
Allowing this option acknowledges the efforts of the industry leaders and encourages others to follow their example. Special required permanent and voluntary temporary labels for heaters certified with cord wood would specify that they meet a PM emissions limit of 0. The Step 2 PM emission Start Printed Page limit for forced-air furnaces matches the hydronic heater alternate cord wood option emission level of 0. The bases for the emission levels are discussed in section V. We are making a single determination of BSER for catalytic, noncatalytic, hybrid, cord wood and pellet heaters and furnaces in order to not restrict open market competition.
We are requiring manufacturers to provide warranties on the catalysts, prohibit the operation of catalytic heaters and furnaces without a catalyst and require operation according to the owner's manual. In addition, we are requiring manufacturers to provide warranties for noncatalytic and hybrid heaters and furnaces and require operation according to the owner's manual.
As discussed at proposal, we considered requiring efficiency standards heat output divided by fuel input to ensure that heaters are efficient and burn no more wood than necessary for the heat demand so that the consumers can save money on fuel and so that the emissions are lower. We did not propose an efficiency standard because we concluded we do not yet have sufficient data, but the final rule uses our section authority to require efficiency testing and reporting to the EPA. This will help better inform consumers so they can choose the best-performing heaters now that will also save them money on fuel costs and also reduce PM emissions by burning less wood.
This will also provide data to states and the EPA as we consider future wood heater rulemaking. However, this rule uses our section authority to require manufacturers to determine CO emissions during the compliance tests as typically conducted , report those results to the EPA and include those results on the manufacturer's Web site. This will help better inform consumers so they can choose the best-performing heaters that have less CO emissions and less health concerns for themselves and their neighbors.
This will also provide data to states and the EPA as we consider future rulemaking. In this final rule, we are not setting limits on visible emissions, and we are not prohibiting use in non-heating seasons. However, operators should note that some state, local and tribal jurisdictions have limits, prohibitions and other requirements that must be followed. Like the subpart AAA requirements, the subpart QQQQ requirements provide additional time for the sale of unsold hydronic heaters manufactured before the compliance date. This additional sell-through time does not include forced-air furnaces because EPA has determined that it is reasonable for forced-air furnace manufacturers to revise their owner's manuals, training and marketing materials to comply with the work practice and operational standards by the effective date.
Go to a specific date
As in subpart AAA, subpart QQQQ includes a list of prohibited fuels because their use would cause poor combustion or even hazardous conditions. As in subpart AAA, subpart QQQQ requires that the owner or operator must operate the hydronic heater or forced-air furnace in a manner that is consistent with the owner's manual and the rule requires the manufacturer to discuss the best operating practices in the owner's manual.
For pellet-fueled appliances, operation according to the owner's manual includes operation only with pellet fuels that are specified in the owner's manual. As in subpart AAA, manufacturers must only specify graded and licensed pellets that meet certain minimum requirements.
Data show that pellet quality is important to ensure that the appliances operate properly such that emissions are within the appliance certification limits. The permanent labeling requirements and owner's manual requirements in subpart QQQQ are similar to the guidelines in the EPA's current voluntary hydronic heater program with some improvements. Like in subpart AAA, the temporary labels hangtags are voluntary and are only for models that meet Step 2 levels before the compliance date and these hangtags end upon the Step 2 compliance date.
Subpart QQQQ also has a cord wood alternative compliance option with a special permanent label and a voluntary temporary label hangtag for models that meet Step 2 using cord wood. The final rule requires that before manufacture and sale at retail, all affected hydronic heaters and forced-air furnaces subject to subpart QQQQ must conduct certification compliance testing, submit a certificate of compliance and receive EPA approval for the Step 1 and Step 2 PM emission limits by the dates shown in Table 4.
For hydronic heaters, we are requiring emission testing, reporting and certification based on crib wood to demonstrate compliance with Step 1 and Step 2 emissions limits. See 40 CFR Based on the existence of viable draft cord wood test methods and the expectation that the ASTM test methods would be final soon after the NSPS proposal and that significant testing of heaters re-tuned to perform well on cord wood would occur before promulgation of this final rule, the EPA proposed to require testing with cord wood for the Step 2 emissions limits. We received numerous comments with concerns about when the cord wood test methods would be ready and how quickly heaters could be redesigned to perform well with cord wood certification testing that we proposed for Step 2, i.
At proposal, we had limited test data for heaters using cord wood. Considering all of the above, we have determined that we do not have sufficient data at this time to adequately support a regulatory requirement for cord wood testing. We will consider alternative cord wood test method requests on a case-by-case basis until we are convinced that improved test methods Start Printed Page have been sufficiently demonstrated that they can be relied upon for regulatory purposes. For now, we will be receptive to alternative test methods requests that use the current ASTM draft methods.
We will also be receptive to other alternative test method requests that are adequately demonstrated, ideally according to the EPA Method validation procedures. In this final rule, the EPA is relying on the cord wood test method that has been developed by the CSA for forced-air furnaces.
The current version of CSA B In this final rule, we are relying on efficiency test methods that have been developed by the CSA. As discussed earlier in section III. However, for forced-air furnaces, we are concerned that there may not be sufficient third-party certifier capacity specific to forced-air furnace testing according to the CSA B We do not want to unfairly restrict the production and sales of forced-air furnace manufacturers who do all the things they should do and then potentially have to wait on EPA approval.
Thus, we have added a conditional, temporary approval by the EPA for forced-air furnaces based on the manufacturer's submittal of a complete certification application. The application must include the full test report by an EPA-approved laboratory and all required compliance statements by the manufacturer. The conditional approval would allow forced-air furnace manufacture and sales for 1 year or until EPA review of the application, whichever is earlier.
Tankless water heating - Wikipedia
The 1-year conditional, temporary approval by the EPA does not apply to hydronic heaters because they have been required to submit third-party certifications for the EPA hydronic heater voluntary partnership program since and will continue to do so under this NSPS. This section is a summary of the significant changes from the proposed rule based on the comments and additional material we received and have carefully considered. As explained in more detail in section V, these final emission limits represent significant advances in stove technology and substantial reductions in emissions, both collectively and from individual units.
Compliance for room heaters will be determined using the weighted average of burn rates rather than requiring each individual burn rate to meet the limit. To reduce potential certification delays and unnecessary costs for small businesses, we are adding an automatic Step 1 EPA approval for models with valid EPA certifications under the NSPS that show that the models achieve the Step 1 emission levels. Manufacturers may choose to test using either crib wood or cord wood. If the manufacturers choose the cord wood alternative compliance option, the PM emission limit for cord wood is 2.
Although the number is higher, the cord wood test method is more reflective of fuel that is used in homes and the data available to the EPA indicate that this PM emission level is at least as stringent as the 2. More details on this are in section V. A Summary of Major Comments and Responses. For new residential hydronic heaters, the final rule keeps the proposed Step 1 weighted average PM emission rate of 0.
The change from the proposed Step 1 cap of 7. To further reduce potential certification delays and unnecessary costs for small businesses, we are also adding automatic Step 1 EPA certification for hydronic heater models certified by NYSDEC that demonstrate the models achieve the Step 1 levels and RHNY-qualified pellet hydronic heaters.
Similarly, we are adding automatic Step 1 EPA certification for new forced-air furnaces that are independently certified i. For forced-air furnaces for Step 1, we deleted the 7.
For hydronic heaters, we are changing the proposed Step 2 PM emissions limit of 0. If the manufacturer chooses the cord wood alternative compliance option, the Step 2 PM emission limit for cord wood is 0. Although the number is higher, the cord wood test method is more reflective of the fuel that is used in homes and the limited cord wood data available to the EPA indicate that this PM emission level is at least as stringent as the 0.
For forced-air furnaces, the Step 2 PM emission level matches the hydronic heater cord wood Start Printed Page alternative option because forced-air furnaces are certified using CSA B Details on the bases of the emission levels are in section V, Summary of Responses to Major Comments. For hydronic heaters and forced-air furnaces tested with cord wood, the EPA is allowing voluntary manufacturers to use special permanent labels and EPA temporary labels hangtags which recognize that cord wood testing more closely reflects actual operation under in-home-use conditions.
Comments indicated that the Masonry Heater Association MHA needs more time to finish their efforts to develop revised test methods, alternative compliance calculation procedures and dimensioning procedures. The MHA comments stated that the cost of testing masonry heaters is high and impractical because almost all are custom-built onsite. After we receive additional information from MHA and others, we will consider if we should take final action for new residential masonry heaters in a future rulemaking. The potential emission impact of this delay is small.
Fewer than 1, masonry heaters are built each year. Most manufacturers build fewer than 15 heaters per year. The total nationwide annual emissions are estimated to be less than 10 tons of PM 2. In section III. D of the preamble to the proposed rule, we described the proposed approach for a third-party certification program by an ISO-accredited certifying body and testing by ISO-accredited testing laboratories. This approach requires manufacturers to use third-party, independent ISO-accredited and EPA-approved test labs and certifying entities to demonstrate compliance with a representative appliance for a model line.
In this final rule, we are increasing the transition period for test laboratories that are currently EPA-accredited from 1 year to 3 years from the effective date of this final rule i. This additional time for test laboratory accreditation will reduce concerns about costs for these small laboratories and potential testing delays.
Calculating Resistive Heating
We proposed that certifying entities be required to receive ISO accreditation upon the effective date of the final rule; however, commenters stated that ISO accreditations can take 6 months. Cost and economic impacts of the proposed rule have been revised to reflect changes to the standards and improved estimates of costs and emissions for room heaters and central heaters. See section VI of this preamble for a discussion of these revised impacts, as well as the RIA and the RTC document for this final rule for more detailed information.
The EPA proposed a number of changes to test methods established under the rule to improve their precision and to better reflect real-world conditions. For Step 2 emission limits, we proposed to require certification compliance at the lowest burn rate Category 1 and the maximum burn rate Category 4 rather than the weighted average of the four burn rates, which was required in the rule.
Many comments on the proposal and the data in the NODA strongly supported the proposed compliance determinations per individual burn rates. Many other comments strongly opposed the proposal. Considering all of the comments and focusing on the available test data, especially the EPA wood stove certification test data by burn rate that we included in the July 1, , NODA, we are requiring certification calculations based on the weighted average of the four burn rates for subpart AAA.
More detail is presented in section V. F, Test Methods. For subpart QQQQ, the final rule uses the weighted average with a cap for each test run for Step 1 for hydronic heaters , but retains the proposed requirement for compliance at each burn rate for Step 2 for both hydronic heaters and forced-air furnaces , given concerns about the sometimes very large emissions at individual burn rates. The emission limits reflect the data available. For a more detailed discussion of these comments and responses, see the RTC document in the docket for this rule.
We still encourage manufacturers to design wood heaters that perform best on cord wood that consumers use. However, considering all of the above, we have determined that we do not have sufficient data at this time to support a regulatory requirement for cord wood testing other than for forced-air furnaces , but rather will allow an alternative compliance option for cord wood testing.
Note that forced-air furnace certification tests are conducted according to CSA B Also, we will be receptive to other alternative test method requests that are adequately demonstrated, ideally according to the EPA Method validation procedures. See section III of this preamble for the specific alternative compliance emissions limit options we are allowing under subparts AAA and QQQQ for manufacturers of heaters who choose to certify compliance with cord wood instead of crib wood. Based on comments and the need to minimize potential testing and certification delays for Step 1, the final rule includes additional test methods for hydronic heaters.
Based on numerous comments from small business manufacturers and small business retailers and some states, we are lengthening the retail sell-through period for subpart AAA from 6 months from the effective date of the final rule to December 31, , approximately 8 months from the expected effective date. That is, no manufacturer, distributor, wholesaler or retailer may sell or offer to sell new stoves after December 31, , that do not meet the Step 1 emission limit.
Eight months will better cover the primary selling period after the rule is final and will affect a very small number of appliances. We are also providing a retail sell-through period for subpart QQQQ hydronic heaters to also cover the primary selling period. We are not allowing a retail sell-through period for forced-air furnaces because the manufacturers and retailers can quickly revise the owner's manuals to add best burn practices to comply with the work practice and operational standards.
Based on the public comments and our additional review of the history of the rule, we have determined that there is no need to make the proposed change to a streamlined Petition for Review process. Therefore, we are retaining the Appeals and Administrative Hearing Procedures outlined in the rule. Some comments indicated that bans of wood burning would be more appropriate.
The EPA is not banning wood burning in this rule because section a 1 of the CAA requires that the emission standards reflect the degree of emission limitation achievable by the application of BSER. Some comments suggested that we develop less stringent standards for rural areas than other areas or no standards in rural areas at all. The EPA is not setting different emission standards for rural areas because section of the CAA does not provide legal authority for differentiated standards based on where the devices are used. Many noncatalytic stove manufacturers and laboratories and some other manufacturers were concerned especially about the stringency of the Step 2 level using cord wood 5 years after the effective date.
We considered all comments and focused on those that discussed the emission data in detail. However, the results of the BNL cord wood tests also showed that emissions from a popular, inexpensive, current-model noncatalytic stove that was not adjusted by the manufacturer for burning cord wood instead of crib wood during the certification test can be much higher than in several cases, over twice as high the crib wood emission test results.
Other comments suggested that we stay with the proposed cord wood testing requirement and proposed Step 2 emission level that some heaters can already meet. We agree with WSDOE that it appears that hybrid stoves may be the best technology capable of meeting Step 2, better than noncatalytic stoves; however, we are concerned about setting required emission levels that may have potential impacts on a large number of small businesses that may not yet have much experience with that technology, and we do not want to prematurely restrict their choices. As discussed in section IV. D, we agree that test methods are needed that better reflect in-home use and include start-up and the lowest burn Start Printed Page rate at which a device may be commonly operated.
As discussed earlier in this preamble, based on the data and comments, we have determined that it is premature to require a cord wood-based Step 2 emission limit at this time. Rather, we are basing the Step 2 requirements on crib wood testing and including an alternative compliance option to encourage manufacturers to certify with cord wood as soon as possible to provide consumers with better information regarding in-home use.
In support of the cord wood alternative compliance option, there are three stove model lines that meet Step 2 using cord wood testing. D of this preamble, we expect additional manufacturers will choose the alternative cord wood compliance testing option so that consumers will have more opportunities to purchase stoves that are tuned for in-home use. For now, we will be receptive to alternative test method requests that use the current ASTM draft methods. We will also be receptive to other alternative test method requests that are adequately demonstrated, ideally according to EPA Method validation procedures.
We expect that within the next few years we will receive enough cord wood test data for the EPA to establish revised certification requirements based on cord wood testing. Thus, the final rule includes a cord wood alternative compliance option for Step 2 and special permanent labels and allows voluntary temporary EPA labels hangtags for units tested with cord wood. As discussed earlier in this section, the proposal reasonably anticipated that all manufacturers would iteratively adjust the combustion air flows, directions and proportions to better match the change in hydrocarbon volatilization rate due to the difference in surface-area-to-volume ratio and spacing for crib wood versus cord wood.
The proposal also reasonably anticipated that manufacturers would have a full complement of cord wood tested heaters available by Step 2, i. Some stoves already perform well on cord wood. However, comments from some small business noncatalytic stove manufacturers, small business laboratories and some states have questioned whether most small business manufacturers could comply with the Step 2 emission limits based on cord wood by that date. As discussed in the NODA, the cord wood test data submitted to us for three catalytic or hybrid wood stoves manufactured by two small businesses show that their EPA-certified wood stoves when tested using cord wood and making no design changes to adjust for testing using cord wood versus crib wood have similar emissions as their stoves do when tested using crib wood.
The cord wood results show that they can achieve an emission limit of 1. Several comments stated that they did not believe these results are representative of most EPA-certified stoves and that typical cord wood values are likely to be higher than the 1. Recognizing that the cord wood alternative compliance option is an option rather than a requirement, we have set the cord wood Step 2 emission level at 2. The cord wood alternative compliance option provides appropriate opportunities to small manufacturers who have been leaders in optimizing for cord wood performance and encourages other manufacturers to follow their example.
More discussion is in the RTC document in the docket for this final rule. We have set the crib wood Step 2 emission limit at 2. Thus, considering the significant emission reductions for this final rule and the potential significant cost impacts for this industry that is comprised of over 90 percent small businesses, and considering that the difference between the proposal and this final rulemaking is less than approximately 36 tons per year compared to the 8, tons per year for this final rulemaking, we judge that a final Step 2 emission level of 2.
Some comments questioned that BSER is adequately demonstrated. The data in the paragraph above show that not only are the emission levels demonstrated, the percentages of current heaters that already meet Step 2 demonstrate the reasonableness of the Step 2 emission limit, especially considering that the Step 2 emission limit becomes applicable 5 years after the effective date.
Some comments recommended that the final rule be as stringent as the cleanest stoves on the market and some comments suggested numbers that reflect the top 5 percentile. As discussed above, considering that the emission reduction difference between the proposal and this final rulemaking is approximately 36 tons per year compared to the 8, tons per year for this final rulemaking , we judge that a final Step 2 BSER of 2. Some comments suggested that the precision of the test method is not good enough to set emission limits more stringent than the NSPS. Even if the commenters' claims were correct that the precision is no better than 1.
Further, we note that the final rule deletes the previously required upward adjustment for Method 5G to 5H, which was sometimes over a 30 percent increase for certification values under the NSPS and the State of Washington DOE that were tested using Method 5G. Comments of many small business manufacturers of hydronic heaters and forced-air furnaces questioned the demonstrations of BSER for hydronic heaters and forced-air furnaces, especially the proposed cord wood Step 2 limit of 0.
As discussed earlier in sections III. C of this preamble, considering the numerous comments expressing concern about whether most small business manufacturers will be ready in time, reviewing the data currently available, and acknowledging that the expected ASTM cord wood test methods are not yet completed at this time, we have determined that it is premature to require cord wood certification tests for hydronic heaters at this time. Rather, we are allowing a cord wood alternative compliance option.
Focusing on the crib wood test primary requirement and crib wood test data, we see that there are already 50 hydronic heater models Phase 2 qualified under the EPA hydronic heater voluntary partnership program, which also meet the Step 1 emission levels of this final NSPS. There are also 19 voluntary program qualification tests recently submitted to the EPA that, if valid, will result in 19 additional Phase 2 model qualifications.
That is, no additional certification will be necessary for these three groups for Step 1. For forced-air furnaces, commenters indicated that the Step 1 p. As discussed earlier, the final rule incorporates the necessary additional time for testing. For new residential hydronic heaters, we have set the crib wood Step 2 emission level at 0.
Considering the potential significant cost impacts for this industry that is comprised of over 90 percent small businesses, and that the relatively small difference in emission reductions between the proposal and this final rulemaking, we judge that a final hydronic heater Step 2 emission level of 0. As with room heaters subpart AAA and for the same reasons, hydronic heaters subpart QQQQ have a cord wood alternative compliance option. Considering that it is an option designed to encourage leadership for others to follow, that it is an option rather than a requirement and that many European models already achieve levels better than 0.
We note that the RHNY emission qualification requirement is 0. Further, we note that even if there were to be method uncertainty on the order of approximately four times the expected precision of 35 percent, models at 0. We have set the same final Step 2 emission level for forced-air furnaces as BSER as we have for hydronic heaters based on the following:.
Since forced-air furnaces and indoor hydronic heaters compete in the same market, wise consumers expect similar performance. We expect most forced-air furnace manufacturers to transfer technology and knowledge from wood stoves and hydronic heaters. Some small forced-air furnaces have already transferred technology from wood heaters to achieve good performance. Several industry comments questioned their ability to transfer technology from hydronic heaters because of their concerns about size limitations in order to install forced-air furnaces indoors going through doorways and other entrances to basements.
They were especially concerned that the space limitations may affect their ability to adequately insulate the models that may be installed in close proximity to combustibles. We acknowledge their concerns but note that coal, oil and natural gas forced-air furnaces and indoor hydronic heaters that have similar space limitations and proximity to combustibles conditions have successfully handled those concerns for many years.
For example, numerous Start Printed Page cord-wood-fired indoor hydronic heaters have been safely installed without large volumes of thermal insulation around the firebox. Many comments stressed the importance of easy public availability of certification test reports especially electronically , limited CBI claims, more details on the EPA Web sites, better labels and more outreach to encourage change outs to cleaner stoves. We agree with these comments and the final rule incorporates this transparency and consumer-friendliness.
Some comments suggested wording clarifications that we have incorporated in the final rule. More details are in the RTC document included in the docket for this rule. Many comments stressed the importance of credible data for the certifications and the value of close EPA oversight, notwithstanding the addition of ISO-accredited laboratories and ISO-accredited certifying entities. Some comments suggested that the EPA should allow the ISO-accredited certifying entities to issue NSPS certificates directly and that the EPA's role should be solely to review the certifications and only question their certificates upon cause.
The small business laboratories requested more time for the transition to ISO-accreditation because of the cost. As discussed earlier in this preamble, the final rule allows a 3-year extension of current EPA accreditations of laboratories and allows 6 months for ISO accreditation of certifying entities, except for hydronic heaters, which have used ISO-accredited certifying entities since October for the EPA voluntary program.
The EPA will retain its approval and oversight functions for this final rule. As also discussed earlier in this preamble, to address the possibility that there may not be sufficient third-party certifier capacity and review and approval capacity by the EPA, especially in the first year, and so as to avoid unfairly restricting the production and sales of manufacturers who do all the things they should do and then potentially have to wait on the EPA approval, we have added a conditional, temporary approval by the EPA for room heaters subject to revised subpart AAA, as well as forced-air furnaces subject to subpart QQQQ, based on the manufacturer's submittal of a complete certification application.
Within 1 year, the manufacturer must submit a certificate of conformity by a third-party certifier. The 1-year conditional, temporary approval by the EPA does not apply to hydronic heaters because they have used third-party certifications for the voluntary program since and will continue to do so under the NSPS. Comments received on the proposed rule included information and opinions regarding the EPA wood heater cost estimates. Details of our responses to cost comments are in the RTC document and the technical cost memoranda in the docket for this final rule.
We have considered all the comments and have revised our cost estimates based on comments that provided additional detailed cost data. The authors indicated that costs would decrease for separate models in the same line by up to 25 percent. These costs include marketing, design, developing first generation, second generation and prototype units; NSPS and safety testing, equipment tooling, etc. The Hearth Patio and Barbecue Association HPBA provided detailed estimates of adjustable burn rate wood stoves and hydronic heater model development costs. According to HPBA, the proposal cost estimates are deficient because they do not reflect specific emission rates or emission performances.
The Ferguson analysis provides cost estimates for four categories of emission reductions based on the proposed emission levels, consisting of modifying 7. The Step 1 cost for 7. The Ferguson analysis shows that several of the cost components are identical across scenarios. The analysis claims, however, that other cost components vary according to the specified emission reduction scenario. These differences were not supported in the comments. For purposes of this analysis, we used the 7.
We did accept the assumptions and logic related to evaluating the tooling cost difference between steel stoves and cast iron stoves, as both are commonly manufactured. Like Ferguson, we used an average of their tooling costs to reflect product differences, even though this may overestimate the number of cast iron stoves in the market place. While we recognize the range in capital cost estimates provided both prior to and after proposal of the draft standards leave room for additional cost scenarios, especially the much lower cost scenario for Woodstock Soapstone Stoves, the Ferguson costs represent the best documented cost ranges and cost categories available at this time.
For the final cost analysis, we used the mean wood stove costs. Further, changes in the measured cold resistance of the layered heater 12 may be used to calculate new TCR values as appropriate. In another form for temperature calibration, the two-wire controller 14 preferably comprises a calibration offset feature that provides for input of a temperature offset parameter. Such an offset is desirable when the location of the layered heater 12 is some distance away from the optimum location for sensing temperature. Thus, the temperature offset parameter may be used such that the heater system 10 provides a temperature that more closely represents the actual temperature at the optimum location.
Turning now to the construction of the layered heater 12 as shown in FIGS. Therefore, the pattern of the resistive layer 24 a is preferably customized for each application of the heater system The patterns illustrated herein are exemplary only and are not intended to limit the scope of the present disclosure. The layered heater 12 , including each of the layers and the terminal pads 28 may also be constructed in accordance with U.
Accordingly, additional specificity with regard to further materials, manufacturing techniques, and construction approaches are not included herein for purposes of clarity and reference is thus made to the patents incorporated by reference herein for such additional information. One form of the two-wire controller 14 is illustrated in block diagram format in FIG. As shown, the two-wire controller 14 generally comprises a power source 50 , a voltage and current measurement component 52 , a power regulator component 54 , and a microprocessor 56 in communication with the layered heater The microprocessor 56 is also in communication with a communications component 58 , where certain output from the heater system 10 e.
Generally, the two-wire controller 14 applies a DC bias, or low level DC current, to the layered heater 12 during an AC power cycle zero-cross interval so that the current value times a nominal heater resistance results in a voltage that is higher than the full wave voltage at the zero crossing for a time period on each side of the zero value. During the time interval, the voltage of the layered heater 12 is amplified and compared to a reference voltage, and power to the layered heater 12 is then controlled as further described herein.
Selecting the Right Sand Heater
Application of the DC bias is further shown and described in U. In another form of the present disclosure, an AC current may be used for the bias instead of the DC bias to determine the resistance of the layered heater As shown, the two-wire controller 14 comprises a transistor 60 , a diode 62 , and a first resistor 64 , wherein the first resistor 64 together with the layered heater 12 form a voltage divider.
For the DC bias, the transistor 60 is turned on for a short time period, e. Additionally, the diode 62 prevents current flow through the power source 50 during positive half cycles when the layered heater 12 is receiving power. The output of the layered heater 12 is then sent through a second resistor 66 and into an opamp circuit 68 that comprises an amplifier 70 and resistors 72 , 74 , and Further, during the DC bias time period, conversion of the output voltage of the amplifier 70 from an analog signal to a digital signal takes place, and a gating pulse from a triac 80 is delivered to the layered heater 12 if the calculated resistance, or layered heater 12 temperature, is such that a control algorithm has determined a need for additional power from the layered heater As further shown, a field effect transistor 82 clamps the input of the amplifier 70 , thereby preventing the amplifier 70 from being over driven during both positive and negative half cycles when the heater is receiving line power.
The microprocessor 56 , which is described in greater detail below, generally communicates with the circuit shown through an output control 84 , a bias control 86 , and heater input The firmware 90 may be programmed for a variety of functions, including but not limited to, allowing half cycle delivery of power to improve controllability or full cycle power in accordance with IEEE As a further example, the firmware 90 may include control algorithms to compensate for thermal transient response and other calibration data as previously described.
Therefore, the microprocessor 56 is used in combination with the DC bias circuitry to determine layered heater 12 temperature and to more efficiently control power to the layered heater A further expansion of the two-wire controller 14 is now shown in greater detail in FIG. The power source 50 is preferably non-isolated and capacitively coupled with a linear regulator as shown. The power source 50 thus regulates an alternating current down to a specified value as required for operation.
As further shown, the sine wave for the zero-cross DC biasing from the power source 50 is in communication with the microprocessor During the zero-cross interval, the DC bias is applied through the transistor , diode , and resistor Measurement of the change in voltage across and current through the layered heater 12 is accomplished using the dual amplifiers and and analog switches and , wherein the change in voltage signal is through amplifier and analog switch , and the change in current is through amplifier and analog switch As further shown, the change in current is measured using a shunt resistor Additionally, the two-wire controller 14 comprises a triac that is out of conduction at the zero-cross and is conducting on each half cycle.
Therefore, two methods of calculating resistance are provided by the circuit shown in FIG. Additionally, although the present disclosure preferably measures voltage and current to determine resistance, alternate methods of determining resistance such as a voltage gate or using a known current may also be employed while remaining within the scope of the present disclosure. In yet another form, the triac is preferably a random fire triac such that the layered heater 12 is fired at high conduction angles to reduce the amount of energy that is delivered to the layered heater 12 during sampling.
Additionally, when using a random fire triac, any rate function may be applied by delivering energy in smaller increments as the temperature or resistance in another form approaches the set point. Accordingly, the layered heater 12 is fired at higher and higher conduction angles into a full line cycle. As further shown, communications to and from the two-wire controller 14 take place on the opposite side of the microprocessor The communications component 58 comprises a series of opto-isolators , , and , in addition to a line transceiver Therefore, communications can be made through any number of protocols, including by way of example, RS communications as illustrated herein.
In addition to other functions, calibration data can be entered utilizing this communications interface. Therefore, certain modifications to the settings within the two-wire controller 14 , including entry of calibration data as previously described, can be accomplished in an efficient manner.
The specific circuit components, along with the values and configuration of the circuit components, e. Accordingly, alternate circuit components, configurations, and values, and resistance measuring circuit topologies may be implemented in a two-wire configuration as defined herein while remaining within the scope of the present disclosure. One known application for the heater system 10 according to the principles of the present disclosure is for hot runner nozzles in injection molding systems as shown in FIG.
The hot runner nozzles are typically disposed within a hot runner mold system , which further comprises a plurality of mold wiring channels that provide for routing of electrical leads not shown that run from heaters not shown disposed proximate the hot runner nozzles to a two-wire controller not shown as described herein.
Since each heater serves as both a heating element and as a temperature sensor, only one set of leads per heater is required rather than one set of leads for the heater and one set of leads for a temperature sensor. As a result, the amount of leads running through the mold wiring channels is reduced in half and the related bulk and complexity is drastically reduced. Additionally, injection molding equipment typically includes an umbilical that runs from the controller to the hot runner mold system , wherein all of the leads and other related electrical components are disposed. With the drastic reduction in the number of leads provided by the present disclosure, the size and bulk of the umbilical is also drastically reduced.
Moreover, since the temperature is being sensed by the entire resistive layer of the heater, the temperature is being sensed over a length rather than at a point with a conventional thermocouple. Referring now to FIGS. The layered heater further comprises a dielectric layer disposed on the substrate , a resistive layer disposed on the dielectric layer , and a protective layer disposed on the resistive layer As further shown, terminal pads are disposed on the dielectric layer and are in contact with the resistive layer Accordingly, the electrical leads are in contact with the terminal pads and connect the resistive layer to the two-wire controller As a result, only one set of electrical leads are required for the heater system , rather than one set for the layered heater and another set for a separate temperature sensor.
As shown in FIG. In yet another form of the present disclosure, a modular solution to retrofitting the heater system according to the present disclosure with existing controllers that use separate temperature sensors, e. As shown, two-wire modules are provided between layered heaters and an existing temperature controller The temperature controller comprises temperature sensor inputs and power outputs The two-wire modules thus contain the two-wire resistance measuring circuit as previously described, and the temperatures calculated within the two-wire modules are transmitted to the temperature sensor inputs of the existing temperature controller Based on these temperature inputs, the temperature controller controls the layered heaters through the power outputs It should be understood that power control may be a part of the temperature controller or may be a separate power controller as shown while remaining within the scope of the present disclosure.
Accordingly, existing temperature controllers can be retrofitted with the two-wire modules to implement the heater system of the present disclosure without substantial rework and modification of existing systems. The heater system comprises a layered heater and a controller that operate as previously described wherein a resistive layer not shown of the layered heater is both a heating element and a temperature sensor. The heater system further comprises a power source , which is preferably low voltage in one form of the present disclosure, that provides power to the layered heater The layered heater is connected to the controller as shown through a single electrical lead and through the body or structure of a device e.
The heater system uses the electrically conductive nature of the device materials to complete the electrical circuit, and thus a power source is required to limit the current level traveling through the device The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the gist of the disclosure are intended to be within the scope of the disclosure.
Such variations are not to be regarded as a departure from the spirit and scope of the disclosure. Effective date : Year of fee payment : 4. Year of fee payment : 8. A hot runner nozzle heater system is provided with a layered heater in communication with a two-wire controller, wherein a resistive layer of the layered heater is both a heater element and a temperature sensor.
The two-wire controller thus determines temperature of the layered heater using the resistance of the resistive layer and controls heater temperature through a power source. FIELD The present disclosure relates generally to hot runner nozzle heater systems and controllers and more particularly to temperature sensing for hot runner nozzle heater systems. SUMMARY In one preferred form, the present disclosure provides a hot runner nozzle heater system comprising at least one hot runner nozzle and at least one resistive layer disposed proximate the runner nozzle, wherein the resistive layer has sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor.
Hot Runner Nozzle Application One known application for the heater system 10 according to the principles of the present disclosure is for hot runner nozzles in injection molding systems as shown in FIG. A hot runner nozzle heater system comprising: at least one hot runner nozzle;.
The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller comprises a DC bias control for calculation of the resistance of the resistive layer. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller comprises an AC bias control for calculation of the resistance of the resistive layer. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller comprises high conduction angle firing. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller comprises a shunt resistor for calculation of the resistance of the resistive layer.
The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller further comprises a microprocessor. The hot runner nozzle heater system according to claim 1 , wherein the two-wire controller further comprises firmware. The coffee machine according to the invention is preferably configured so that the pipe and the at least one heating rod are held together by a sleeve. Such a sleeve is to be preferred to a complex housing with regard to manufacturing simplicity.
Glo-Warm Natural Gas Heater Manual
The sleeve can be made of heat-resistant plastic or of metal. It is usefully provided that a temperature sensor is provided on the sleeve. Since the sleeve is preferably located at the centre of the elongated continuous heater to hold the components securely together, it is located at a preferred site for a temperature sensor.
In this respect, it is possible to arrange a temperature sensor in the area of the sleeve and mount this on the sleeve. These flexible tube connecting pieces can be internally or externally sealing and provide a simple possibility for pushing on a hose for supplying or removing water. It is usefully provided that the connecting pieces are provided with seals.
By this means a reliable seal can be provided at the transition between the pipe of the continuous heater and the flexible tube connection pieces. In this connection, it is particularly useful that the connecting pieces are made of plastic and comprise securing means for securing the continuous heater on the housing of the coffee machine.
A heat-resistant plastic provides good heat insulation between the continuous heater and the housing or the hoses. Furthermore, securing means for centring the continuous heater in the housing and which provide the possibility of securing the continuous heater, can be moulded simply on the flexible tube connecting pieces made of plastic. It is likewise useful if holders for further components are provided on the securing means. For example, these components can comprise sensors or switches.
The invention is based on the finding that a continuous heater for a coffee machine can be fabricated simply if this substantially consists of a flattened pipe and heating rods abutting thereagainst. The invention is now explained in detail with reference to the accompanying drawings using particularly preferred embodiments. In the figures:. In the following description of the drawings the same reference numerals denote the same or comparable components. The coffee machine 10 comprises a flat front portion 12 and a columnar rear assembly Cups for removing coffee via an outlet 16 can be arranged on the front portion A water container 18 is inserted in the rear assembly The rear assembly 14 further comprises a brewing chamber 20 formed by a coffee pad retainer 24 which can be supplied with a drawer and an elastic retainer cover 28 as the upper portion of the brewing chamber A lever mechanism is provided with a lever 26 in order to seal the coffee pad retainer 24 and the retainer cover 28 with respect to one another after inserting the drawer In the state shown the lever mechanism pulls the coffee pad retainer 24 towards the retainer cover Components for supplying water, for heating water and for controlling these processes are provided inside the housing formed by the front portion 12 and the rear assembly Located in the lower housing area at the boundary between the front portion 12 and the rear assembly 14 is a pump 32 to which water is supplied from the water container 18 via a hose The pump 32 is connected to the continuous heater 38 by means of another hose Important components of this continuous heater 38 are a pipe 40 used to carry water and two heating rods 42 , 44 , These heating rods 42 , 44 each have two electrical connections 46 , 48 to which the heating voltage is applied.
Provided on the front portion 12 of the coffee machine 10 is a keypad 50 which is connected to a printed circuit board 52 , said printed circuit board 52 preferably controlling all the functions of the coffee machine, especially the functions with regard to the conveyance and heating of the water.
Starting from the printed circuit board 52 there is provided a cable run 54 which combines the electrical leads via which the electronic controller delivers its control commands and receives input information. This input information particularly relates to the temperature of the continuous heater detected by a temperature sensor 56 and preferably further temperature information which is recorded by temperature sensors at measuring points 58 , 60 downstream or upstream from the continuous heater 38 in the direction of flow.
gohu-takarabune.com/policy/rastrear/zuraf-espiar-un.php A reed switch 62 is further provided in the rear assembly The task of the reed switch 62 is to electrically detect a minimum filling level in the water container For this purpose a float comprising a magnet is located vertically displaceably in the water container When the water falls below a minimum filling volume in the water container 18 , the magnetic float is located near to the reed switch 22 and makes this switch on, closing a circuit which transmits a signal to the electronic controller that the level is too low.
If the level in the water container is lower than the minimum filling volume, the coffee machine cannot be operated. The continuous heater 38 can also have a sensor which prevents any running dry during the heating process. Contact surfaces 84 , 86 of the heating rods 42 , 44 are constructed as flat and are connected to corresponding contact surfaces or flattened sections of the pipe Thus, good abutment and consequently good heat transfer can be achieved between the heating rods 42 , 44 and the pipe The contact surfaces 84 , 86 preferably extend over the entire or almost the entire length of the continuous heater 38 , a radial position of the contact surfaces 84 , 86 being shown by the broken lines in FIG.
The arrangement of pipe 60 and heating rods 42 , 44 is held together by a sleeve 64 which can be made of heat-resistant plastic or metal.
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The temperature sensor 56 is located in the area of this sleeve Flexible tube connecting pieces 66 , 68 are attached to the ends of the pipe In the present exemplary embodiment, these are inserted in the pipe 60 and fitted with a circumferential seal 70 , 72 , for example, an O-ring.
Related Heater Vol. 01 No. 03
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