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507270-03B

Page 2 of 58

Issue 1904

Unit Dimensions

1

 

NOTE

 - 

C*20  and  D*20  (5  Ton)  size  units  installed  in  upflow 

applications that require air volumes of 1800 cfm (850 L/s) or greater 

must have one of the following:
1.  Single side return air with transition, to accommodate 20 x 25 x 1 

in. (508 x 635 x 25 mm) cleanable air filter. (Required to maintain 

proper air velocity.)

2.  Single side return air with optional “RAB” 

R

eturn 

A

ir 

B

ase.

3.  Bottom return air.

4.  Return air from both sides.

5.  Bottom and one side return air.

See Blower Performance tables for additional information.

2

 Optional External Side Return Air Filter kit is not for use with optional 

Return Air Base.

*  Consider  sizing  requirements  for  optional  IAQ  equipment  before 

cutting side return opening.

FRONT VIEW

SIDE VIEW

Capacity

A

B

C

D

in.

mm

in.

mm

in.

mm

in.

mm

045-08

 

070-12

17-1/2

446

16-3/8

416

16

406

1-5/8

194

090-12 

090-16 

110-20

21

533

19-7/8

505

19-1/2

495

9-3/8

238

135-20

24-1/2

622

23-3/8

594

23

584

11-1/8

238

Summary of Contents for BG921UH

Page 1: ...or loss of life Installation and service must be performed by a licensed professional installer or equivalent service agency or the gas supplier WARNING As with any mechanical equipment personal injury can result from contact with sharp sheet metal edges Be careful when you handle this equipment CAUTION Table of Contents Unit Dimensions 2 Parts Arrangement 3 Gas Furnace 4 Shipping and Packing List...

Page 2: ... air with optional RAB Return Air Base 3 Bottom return air 4 Return air from both sides 5 Bottom and one side return air See Blower Performance tables for additional information 2 Optional External Side Return Air Filter kit is not for use with optional Return Air Base Consider sizing requirements for optional IAQ equipment before cutting side return opening FRONT VIEW SIDE VIEW Capacity A B C D i...

Page 3: ...507270 03B Page 3 of 58 Issue 1904 Parts Arrangement Figure 1 ...

Page 4: ...ng and Packing List 1 Assembled Gas Furnace 1 Bag assembly containing the following 1 Snap bushing 1 Snap Plug 1 Wire tie 1 Condensate trap 1 Condensate trap cap 1 Condensate trap clamp 1 2 diameter debris screen 1 3 4 Threaded street elbow NOTE The required bellows grommet is field provided See the Gas Piping section for relevant diagrams Check equipment for shipping damage If you find any damage...

Page 5: ...od practice requirements and current National Fuel Gas Code or CSA B149 standards NOTE Furnace must be adjusted to obtain a temperature rise within the range specified on the unit nameplate Failure to do so may cause erratic limit operation and premature heat exchanger failure This furnace must be installed so that its electrical components are protected from water Installed in Combination with a ...

Page 6: ...S ALL OF THE FOLLOWING CRITERIA ARE MET a Furnace must be in its final location The vent system must be permanently installed per these installation instructions b Furnace must be installed as a two pipe system and one hundred percent 100 outdoor air must be provided for combustion air requirements during construction c A room thermostat must control the furnace The use of fixed jumpers that will ...

Page 7: ...sion from the National Fuel Gas Code ANSI Z223 1 NFPA 54 This reprinted material is not the complete and official position of ANSI on the referenced subject which is represented only by the standard in its entirely In Canada refer to the CSA B149 Installation codes Do not install the furnace in a corrosive or contaminated atmosphere Meet all combustion and ventilation air requirements as well as a...

Page 8: ... be within 12 305 mm of the top of the enclosure and one within 12 305 mm of the bottom These openings must communicate directly or by ducts with the outdoors or spaces crawl or attic that freely communicate with the outdoors or indirectly through vertical ducts Each opening shall have a minimum free area of 1 square inch per 4 000 Btu 645 mm per 59 kW per hour of total input rating of all equipme...

Page 9: ...ed Inlet Air Minimum 12 in 305mm above Crawl Space Floor Coupling or 3 in to 2 in Transition Field Provided See Maximum Vent Lengths table NOTE The inlet and outlet air openings shall each have a free area of at least one square inch per 4 000 Btu 645 mm2 per 1 17 kW per hour of the total input rating of all equipment in the enclosure Figure 10 Equipment in Confined Space All Air from Outside Ship...

Page 10: ...rnace can result in personal injury or death Combustion and flue products must never be allowed to enter the return air system or air in the living space Use sheet metal screws and joint tape to seal return air system to furnace In platform installations with furnace return the furnace should be sealed airtight to the return air plenum A door must never be used as a portion of the return air duct ...

Page 11: ...er combustible materials other than wood flooring Markings are provided on both sides of the furnace cabinet for installations that require side return air Cut the furnace cabinet at the maximum dimensions shown on Page 2 Furnace applications which include side return air and a condensate trap installed on the same side of the cabinet trap can be installed remotely within 5 ft require either a ret...

Page 12: ...tion Installation Clearances Top Plenum 1 in 25 mm Front 0 Back 0 Sides 0 Vent 0 Floor 0 Front clearance in alcove installation must be 24 in 610 mm Maintain a minimum of 24 in 610 mm for front service access Allow proper clearances to accommodate condensate trap For installations on a combustible floor do not install the furnace directly on carpeting tile or other combustible materials other than...

Page 13: ... unit is not equipped with a filter or rack Afield provided filter is required for the unit to operate properly Table 1 list recommended filter sizes A filter must be in place whenever the is operating Table 1 Furnace Cabinet Width Filter Size Side Return Bottom Return 17 1 2 16 x 25 x 1 1 16 x 25 x 1 1 21 20 x 25 x 1 1 24 1 2 16 x 25 x 1 2 24 x 25 x 1 1 Duct System Use industry approved standards...

Page 14: ...r vent pipe hangers Uniformly apply a liberal coat of PVC primer for PVC or use a clean dry cloth for ABS to clean inside socket surface of fitting and male end of pipe to depth of fitting socket Canadian Applications Only Pipe fittings primer and solvent cement used to vent exhaust this appliance must be certified to ULC S636 and supplied by a single manufacturer as part of an approved vent exhau...

Page 15: ...fter pipe is fully inserted to distribute cement evenly Do not turn ABS or cellular core pipe NOTE Assembly should be completed within 20 seconds after last application of cement Hammer blows should not be used when inserting pipe 8 After assembly wipe excess cement from pipe at end of fitting socket A properly made joint will show a bead around its entire perimeter Any gaps may indicate an improp...

Page 16: ... leakage corrosion or other deficiencies which could cause an unsafe condition 3 Close all building doors and windows and all doors between the space in which the appliances remaining connected to the common venting system are located and other spaces of the building Turn ON clothes dryers and any appliances not connected to the common venting system Turn ON any exhaust fans such as range hoods an...

Page 17: ...t the maximum pipe lengths permitted for BG921UH Table 6A through Table 6C list the maximum pipe lengths permitted for BG951UH Regardless of the diameter of pipe used the standard roof and wall terminations described in section Exhaust Piping Terminations should be used Exhaust vent termination pipe is sized to optimize the velocity of the exhaust gas as it exits the termination Refer to Table 8 I...

Page 18: ...ipe diameter Figure 24 045 070 090 110 135 Standard or Concentric See Table 3 Intake or Exhaust 2 2 1 2 or 3 Furnace capacity 1 Which termination 2 Which needs most elbows 3 How many 4 Desired pipe size 5 What is the altitude 6 Use Table 5 or Table 6 to find max pipe length 7 ...

Page 19: ...n a 75 60 28 97 97 78 9 36 21 70 55 23 92 92 73 10 31 16 65 50 18 87 87 68 Concentric Termination Elevation 0 10 000 ft Number of 90 Elbows Used 2 Pipe 2 1 2 Pipe 3 Pipe Capacity Capacity Capacity 045 070 090 045 070 090 045 070 090 1 68 53 37 100 85 59 116 116 109 2 63 48 32 95 80 54 111 111 104 3 58 43 27 90 75 49 106 106 99 4 53 38 22 85 70 44 101 101 94 5 48 33 17 80 65 39 96 96 89 6 43 28 12 ...

Page 20: ...ipe Capacity Capacity Capacity 045 070 090 045 070 090 045 070 090 1 66 51 29 95 80 48 112 112 93 2 61 46 24 90 75 43 107 107 88 3 56 41 19 85 70 38 102 102 83 4 51 36 14 80 65 33 97 97 78 5 46 31 9 75 60 28 92 92 73 6 41 26 4 70 55 23 87 87 68 7 36 21 n a 65 50 18 82 82 63 8 31 16 60 45 13 77 77 58 9 26 11 55 40 8 72 72 53 NOTE Additional vent pipe and elbows used to terminate the vent pipe outsi...

Page 21: ... 97 97 78 78 74 9 36 21 70 55 23 92 92 73 73 69 10 31 16 65 50 18 87 87 68 68 64 Standard Termination Elevation 4 501 10 000 ft Number of 90 Elbows Used 2 Pipe 2 1 2 Pipe 3 Pipe Capacity Capacity Capacity 045 070 090 110 135 045 070 090 110 135 045 070 090 110 135 1 76 61 39 n a n a 110 95 63 38 n a 132 132 113 113 109 2 71 56 34 105 90 58 33 127 127 108 108 104 3 66 51 29 100 85 53 28 122 122 103...

Page 22: ...4 81 81 74 74 65 9 28 13 60 45 19 76 76 69 69 60 10 23 8 55 40 14 71 71 64 64 55 Concentric Termination Elevation 4 501 10 000 ft Number of 90 Elbows Used 2 Pipe 2 1 2 Pipe 3 Pipe Capacity Capacity Capacity 045 070 090 110 135 045 070 090 110 135 045 070 090 110 135 1 68 53 37 n a n a 100 85 59 34 n a 116 116 109 109 100 2 63 48 32 95 80 54 29 111 111 104 104 95 3 58 43 27 90 75 49 24 106 106 99 9...

Page 23: ...5 65 43 8 83 82 63 63 59 8 31 16 60 60 38 3 78 77 58 58 54 9 26 11 55 55 33 n a 73 72 53 53 49 10 21 6 50 50 28 68 67 48 48 44 Standard Termination Elevation 4 501 10 000 ft Number of 90 Elbows Used 2 Pipe 2 1 2 Pipe 3 Pipe Capacity Capacity Capacity 045 070 090 110 135 045 070 090 110 135 045 070 090 110 135 1 66 51 29 n a n a 95 95 73 38 n a 113 112 93 93 89 2 61 46 24 90 90 68 33 108 107 88 88 ...

Page 24: ...507270 03B Page 24 of 58 Issue 1904 Figure 25 Figure 26 ...

Page 25: ...the next two steps when installing the unit in Direct Vent applications where combustion air is taken from outdoors and flue gases are discharged outdoors The provided air intake screen must not be used in direct vent applications outdoors 1 Use transition solvent cement or a sheet metal screw to secure the intake pipe to the inlet air connector 2 Route piping to outside of structure Continue with...

Page 26: ...orward or to either side in the upflow position and either straight out or downward in the horizontal position Figure 30 The air intake piping must not terminate too close to the flooring or a platform Ensure that the intake air inlet will not be obstructed by loose insulation or other items that may clog the debris screen 2 If intake air is drawn from a ventilated attic Figure 31 or ventilated cr...

Page 27: ...le 7 Maximum Allowable Exhaust Vent Pipe Length in ft without Insulation in Unconditioned Space for Winter Design Temperatures Single Stage High Efficiency Furnace Winter Design Temperatures1 ºF ºC Vent Pipe Diameter Unit Input Size 045 070 090 110 135 32 to 21 0 to 6 PVC 2 PP PVC 2 PP PVC 2 PP PVC 2 PP PVC 2 PP 2 in 18 16 31 28 50 48 30 30 N A N A 2 1 2 in 13 N A 24 N A 42 N A 56 N A N A N A 3 in...

Page 28: ...earance under veranda porch deck or balcony 12 Equal to or greater than soffit depth 3 feet 9m 12 3 feet 9m within a height 15 feet 4 5m above the meter regulator assembly 3 feet 9m 6 inches 152mm for appliances 10 000 Btuh 3kw 12 inches 305mm for appliances 10 000 Btuh 3kw and 100 000 Btuh 30kw 36 inches 9m for appliances 100 000 Btuh 30kw 3 feet 9m above if within 10 feet 3m horizontally 6 feet ...

Page 29: ...es 152mm for appliances 10 000 pliances 10 000 Btuh 3kw and 50 000 pliances 50 000 Btuh 15kw 6 inches 152mm for appliances 10 000 Btuh 3kw 12 inches 305mm for appliances 10 000 Btuh 3kw and 100 000 Btuh 30kw 36 inches 9m for appliances 100 000 Btuh 30kw 3 feet 9m above if within 10 feet 3m horizontally 6 feet 1 8m 7 feet 2 1m 12 inches 305mm 1 In accordance with the current ANSI Z223 1 NFPA 54 Nat...

Page 30: ...ternational B149 installation codes the minimum allowed distance between the combustion air intake inlet and the exhaust outlet of other appliances shall not be less than 12 inches 305 mm IMPORTANT Details of Intake and Exhaust Piping Terminations for Direct Vent Installations NOTE In Direct Vent installations combustion air is taken from outdoors and flue gases are discharged to outdoors NOTE Flu...

Page 31: ...7 If intake and exhaust piping must be run up a side wall to position above snow accumulation or other obstructions piping must be supported every 24 610 mm as shown in Figure 44 Exhaust and intake piping that is run up a wall is considered to be in an unconditioned space so piping should be sized according to Table 7 The intake piping may be equipped with a 90 elbow turndown Using turndown will a...

Page 32: ...FITTINGS PROVIDE SUPPORT OF PIPE ON TOP PLATE ALTERNATE INTAKE PIPE INTAKE PIPE INSULATION optional EXTERIOR PORTION OF CHIMNEY INSULATE TO FORM SEAL SHEET METAL TOP PLATE Minimum 12 305MM above chimney top plate or average snow accumulation 8 12 203MM 305MM 3 8 76MM 203MM SIZE TERMINATION PIPE PER EXHAUST PIPE TERMINATION SIZE REDUCTION TABLE NOTE Do not discharge exhaust gases directly into any ...

Page 33: ...e grade or average snow accumulation B Horizontal separation between intake and exhaust C Minimum from end of exhaust to inlet of intake D Exhaust pipe length E Wall support distance from top of each pipe intake exhaust 12 305 mm Min 12 305 mm Min 6 152 mm Min 24 610 mm Max 9 227 mm Min 12 305 mm Min 16 405 mm Max 6 152 mm Max 6 152 mm Min 24 610 mm Max 9 227 mm Min 12 305 mm Min 20 508 mm Max 6 1...

Page 34: ...n Kit 15F75 or 44J41 UNCONDITIONED ATTIC SPACE 3 76MM OR 2 51MM PVC PROVIDE SUPPORT FOR EXHAUST LINES 12 305MM ABOVE AVE SNOW ACCUMULATION SIZE PER EXHAUST PIPE TERMINATION SIZE REDUCTION TABLE Figure 46 Non Direct Vent Field Supplied Wall Termination SIZE TERMINATION PER EXHAUST PIPE TERMINATION SIZE REDUCTION TABLE Figure 47 Non Direct Vent Field Supplied Wall Termination Extermination SIZE TERM...

Page 35: ...Termination Drain Trap assembled Figure 49 Kit 51W18 USA 15Z70 Canada Parts Identification and Assembly Exhaust from Furnace To Termination Exhaust from Furnace To Termination Kit 51W18 is shown Figure 50 Crawl Space Vent Pipe Drain Trap Assembled Incorrectly Figure 51 Upflow or Downflow Furnace with Exhaust through Crawl Space KIT 51W18 USA Basement Floor To Termination 1 2 PVC to Code Approved D...

Page 36: ...fittings glue all joints Glue the provided drain trap as shown in Figure 58 Route the condensate line to an open drain Condensate line must maintain a 1 4 downward slope from the furnace to the drain Do not use copper tubing or existing copper condensate lines for drain line CAUTION 5 Install field provided vent on trap assembly as shown in Figure 53 through Figure 59 Trap must extend at least 1 a...

Page 37: ... Piping from furnace must slope down a minimum of 1 4 per ft toward trap Figure 55 Evaporator Coil Using a Separate Drain Figure 56 Evaporator Coil Using a Common Drain Piping from furnace must slope down a minimum of 1 4 per ft toward trap Figure 57 Evaporator Coil Using a Common Drain Unit shown in horizontal left hand discharge position ...

Page 38: ...507270 03B Page 38 of 58 Issue 1904 Figure 58 Trap Drain Assembly Using 1 2 PVC or 3 4 PVC ...

Page 39: ... or gas vents dumb waiters or elevator shafts Center gas line through piping hole Gas line should not touch side of unit See Figure 61 and Figure 62 4 Piping should be sloped 1 4 per 15 feet 6 mm per 5 6 m upward toward the gas meter from the furnace The piping must be supported at proper intervals every 8 to 10 feet 2 44 to 3 05 m using suitable hangers or straps Install a drip leg in vertical pi...

Page 40: ...w the safety warnings exactly could result in serious injury death or property damage Never use an open flame to test for gas leaks Check all connections using a commercially available soap solution made specifically for leak detection Some soaps used for leak detection are corrosive to certain metals Carefully rinse piping thoroughly after leak test has been completed WARNING Figure 61 Gas Piping...

Page 41: ...0 16 42 530 15 01 490 13 87 460 13 03 430 12 18 400 11 33 1 1 2 38 1 1 610 40 894 2100 59 46 460 41 34 1180 33 41 990 28 03 900 25 48 810 22 94 750 21 24 690 19 54 650 18 41 620 17 56 2 50 8 2 067 52 502 3950 111 85 2750 77 87 2200 62 30 1900 53 80 1680 47 57 1520 43 04 1400 39 64 1300 36 81 1220 34 55 1150 32 56 2 1 2 63 5 2 469 67 713 6300 178 39 4350 123 17 3520 99 67 3000 84 95 2650 75 04 2400...

Page 42: ...tat check to make sure the wires will be long enough for servicing at a later date Make sure that thermostat wire is long enough to facilitate future removal of blower for service Complete the wiring connections to the equipment Use the provided unit wiring diagram and the field wiring diagram shown in Figure 66 Use 18 gauge wire or larger that is suitable for Class II rating for thermostat connec...

Page 43: ...indoor blower will run continuously on the heating speed when there is no cooling or heating demand 2 When the furnace is running in the heating mode the indoor blower will run on the heating speed 3 When there is a cooling demand the indoor blower will run on the cooling speed Generator Use Voltage Requirements The furnace requires 120 volts 10 Range 108 volts to 132 volts The furnace operates at...

Page 44: ...507270 03B Page 44 of 58 Issue 1904 Figure 67 Typical Wiring Diagram ...

Page 45: ...or property damage Should the gas supply fail to shut off or if overheating occurs shut off the gas valve to the furnace before shutting off the electrical blower deck before performing any service procedure WARNING Before attempting to perform any service or maintenance turn the electrical power to unit OFF at disconnect switch CAUTION BEFORE LIGHTING the unit smell all around the furnace area fo...

Page 46: ...er to the unit 11 Set the thermostat to desired setting NOTE When unit is initially started steps 1 through 11 may need to be repeated to purge air from gas line 12 If the appliance will not operate follow the instructions Turning Off Gas to Unit and call your service technician or gas supplier Turning Off Gas to Unit 1 Set the thermostat to the lowest setting 2 Turn off all electrical power to th...

Page 47: ...for the unit to stabilize observe the flame Flame should be stable and should not lift from burner Natural gas should burn blue 4 After allowing unit to stabilize for 5 minutes record manifold pressure and compare to value given in Table 12 NOTE Shut unit off and remove manometer as soon as an accurate reading has been obtained Take care to remove barbed fitting and replace threaded plug Proper Co...

Page 48: ...witch Requirements at Varying Altitudes Capacity 0 4500 ft 0 1371m 4501 7500 ft 1371 2286m 7501 10000 ft 2286 3048m 045 No Change 11J09 11J10 070 090 Pressure switch is factory set No adjustment necessary All models use the factory installed pressure switch from 0 4500 feet 0 1371 m BG951UH Pressure Switch Requirements at Varying Altitudes Capacity 0 4500 ft 0 1371m 4501 7500 ft 1371 2286m 7501 10...

Page 49: ...m 2 Visually inspect the venting system for proper size and horizontal pitch Determine there is no blockage or restriction leakage corrosion or other deficiencies which could cause an unsafe condition 3 To the extent that it is practical close all building doors and windows and all doors between the space in which the appliances connected to the venting system are located and other spaces of the b...

Page 50: ...mostat Heat Anticipation Set the heat anticipator setting if adjustable according to the amp draw listed on the wiring diagram that is attached to the unit Electrical 1 Check all wiring for loose connections 2 Check for the correct voltage at the furnace with furnace operating Correct voltage is 120 VAC 10 3 Check amp draw on the blower motor with the blower access panel in place Motor Nameplate__...

Page 51: ...0 1030 400 0 10 1565 660 1365 545 1150 465 1020 385 0 20 1535 630 1340 525 1150 440 1025 375 0 30 1440 600 1300 500 1110 420 1000 350 0 40 1405 570 1255 470 1075 400 975 345 0 50 1340 535 1200 445 1045 380 945 330 0 60 1255 500 1125 420 995 355 875 310 0 70 1165 475 1080 395 935 335 820 290 0 80 1060 455 990 365 870 315 750 265 0 90 955 425 895 345 750 285 660 245 BG921UH090CP12 Performance Less F...

Page 52: ...0 0 10 1995 880 1705 760 1390 635 1205 525 0 20 1925 835 1675 715 1405 605 1205 505 0 30 1850 795 1640 680 1400 580 1170 490 0 40 1790 760 1575 645 1395 560 1170 475 0 50 1700 725 1540 625 1350 535 1140 450 0 60 1610 690 1455 580 1295 505 1100 430 0 70 1540 645 1365 550 1225 480 1030 405 0 80 1415 615 1265 510 1125 445 980 385 0 90 1270 565 1165 470 1060 420 900 350 NOTE All air is measured extern...

Page 53: ...480 880 380 0 10 1560 665 1320 565 1085 470 885 375 0 20 1515 630 1300 540 1080 460 880 370 0 30 1465 590 1275 520 1065 440 890 360 0 40 1410 570 1235 490 1050 420 875 350 0 50 1345 540 1195 470 1020 400 840 335 0 60 1275 510 1140 440 975 365 830 315 0 70 1195 485 1090 410 930 355 780 290 0 80 1105 460 995 380 850 325 730 275 0 90 985 420 890 345 770 300 650 255 BG951UH090CP12 Performance Less Fil...

Page 54: ...85 815 1640 685 1995 1145 1900 955 1775 805 1555 680 0 60 1935 1135 1770 930 1540 780 1590 660 1920 1110 1785 910 1695 775 151 645 0 70 1805 1085 1720 895 1480 750 1505 630 1780 1070 1710 885 1590 745 1440 630 0 80 1730 1065 1590 855 1405 720 1455 610 1680 1045 1570 845 1520 710 1350 610 0 90 1645 1010 1520 840 1340 705 1400 595 1595 1010 1540 830 1445 695 1315 600 BG951UH135DP20 Performance Less ...

Page 55: ...y to empty condensate water 3 Remove the clean out cap from the condensate trap and empty water Inspect the trap then reinstall the clean out cap Cleaning Heat Exchanger If cleaning the heat exchanger becomes necessary follow the below procedures and refer to Figure 1 when disassembling unit Use papers or protective covering in front of furnace while removing heat exchanger assembly 1 Turn off ele...

Page 56: ... the 2 pin plug to the wire harness 38 Reconnect drain tubes between flue collar and cold end header box 39 Secure burner assembly to vestibule panel using four existing screws Burners are self aligning to center of clam shells 40 Reconnect gas supply line to gas valve 41 Reconnect flame rollout switch wires 42 Reconnect sensor wire and reconnect 2 pin plug from ignitor 43 Reconnect wires to gas v...

Page 57: ...tions that may result in unsafe operation For instance items innocently stored next to the furnace may obstruct the combustion air supply This could cause incomplete combustion and the production of carbon monoxide gas Table 14 Diagnostic Codes LED Status Fault Description LED Off No power to control or control hardware fault detected LED On Normal operation 1 Flash Flame present with gas valve of...

Page 58: ...m height of eight 8 feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment The sign shall read in print size no less than one half 1 2 inch in size GAS VENT DIRECTLY BELOW KEEP CLEAR OF ALL OBSTRUCTIONS 4 INSPECTION The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall not app...

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