Laars Mighty Therm 2 Owner's manual

Using “Genuine Laars” parts will ensure accurate replacement and warranty coverage.
Installation and Operation Manuals for current products are available on-line at www.Laars.com
Our Commitment
We believe the availability of factory authorized replacement parts is an essential component of customer service. We strive to
provide every opportunity for our customers to order and stock factory authorized replacement parts, including special incentive,
pricing and freight programs. Contact your Laars representative or sales manager for more details.
Ordering
Laars sells parts only through its normal distribution channels. The most commonly used parts are listed in this parts guide, and
can be ordered through Laars stocking representatives or wholesalers. Call the Service Department for assistance in identifying
parts not listed. Have the model and serial number of the unit before calling to assure accurate parts identification. Rush Orders:
We make every effort to ship rush orders the same day at our regular prices, but cannot guarantee same day shipment. Express
freight charged by carriers is not refundable regardless of ship date; please indicate alternate shipping choice if order cannot
ship the same day. Some parts are subject to price changes and limited availability. Laars representatives or wholesalers should
call the factory for price and lead time for non-current sheet metal parts, parts listed as “limited to stock on hand” and parts not
listed in this document.
Terms and Conditions
1. Standard terms will apply to all parts orders.
2. Special pricing is available for bulk quantity orders. Contact the Customer Service Department for pricing and specifics.
3. Expedite fee for non-stocked heat exchangers, 24 hour turnaround $250.00 net.
4. Expedite fee for non-stocked sheet metal parts (7 working days) is $250.00 per part.
5. Cancellation fee for custom product already in production: $250
6. All parts are shipped FOB warehouse.
7. Any excise or sales tax will be charged to and paid by the buyer. Buyer is solely responsible for providing valid resale
certificates.
Salable Returns / Unused Parts
Parts in new condition with all original packaging will be considered for return within one year of date of purchase from Laars,
subject to a 25% restocking charge and recovery of other discounts or incentives earned at time of purchase. Invoice number
and date of purchase must be furnished. Refunds will be made to the original purchaser only, and will be made at the sole
discretion of Laars. Return of parts may affect eligibility for other programs. Contact your Laars representative for more informa-
tion.
Parts Limited Warranty
Laars warrants all parts to be free from defects in materials and workmanship to the original retail purchaser for one year from
date of retail purchase. Proof of purchase is required. This limited warranty applies only to parts purchased for use as an original
equipment replacement part in Laars Heating Systems boilers and water heaters. At its option, Laars will repair or replace any
part that fails under this limited warranty. Repair or replacement shall be the sole remedy, and Laars shall not be liable for any
field labor, removal, transportation to/from the factory, reinstallation or any other such costs.
Return Under Warranty
Parts should be returned to the place of purchase for warranty evaluation. If the original place of purchase is not known, contact
your Laars wholesaler, factory representative or Contract Service Center. Wholesalers, factory representatives and Contract
Service Centers returning parts for warranty consideration must obtain a RMA (Return Merchandise Authorization) number from
the Customer Service Department. Each part must be tagged with the original purchase date, model and serial number of the
boiler it was installed on, and a description of the failure. Parts must be returned freight prepaid and clearly marked with the RMA
number. The RMA expires if not returned within 60 days of issuance. Contact your Laars representative or the Customer Service
Department for more information on obtaining warranty coverage on large, heavy or bulky items.
Laars Heating Systems maintains a policy of continuous quality improvement.
Laars Heating Systems Company reserves the right to change specifications, components, features, or to discontinue products without notice. While
Laars will make every reasonable effort to provide advance notice of changes, supplier actions, changes in code requirements, and Laars' efforts to
continuously upgrade products will sometimes require that changes be introduced with minimal or no advance notice.

Mighty Therm2Page 33
IItem Description Size Size Size Size Size Size Size
500 750 1000 1250 1500 1750 2000
Sheet Metal Components - See Figure 23
1 Panel, Jacket, Front 5F3320 7F3320 10F3320 12F3320 15F3320 17F3320 20F3320 2 Panel, Jacket, Side, Lower Left 5F3420 5F3420 5F3420 5F3420 5F3420 5F3420 5F3420 3 Panel, Jacket, Side, Lower Right 5F3520 5F3520 5F3520 5F3520 5F3520 5F3520 5F3520 4 Panel, Side, Top Left, Jacket 5F3400 5F3400 5F3400 5F3400 5F3400 5F3400 5F3400 5 Panel, Side, Top Right, Jacket 5F3500 5F3500 5F3500 5F3500 5F3500 5F3500 5F3500 6 Panel, Rear, Jacket 5F3220 7F3220 10F3220 12F3220 15F3220 17F3220 20F3220 7 Panel, Top, Jacket 5F3021 7F3021 10F3021 12F3021 15F3021 17F3021 20F3021 8 Weldment, Vent Plate 5F3100 7F3100 7F3100 12F3100 12F3100 12F3100 20F3100 9 Weldment,Housing,Air Inlet/Filter 5F3800 5F3800 10F3800 12F3800 12F3800 12F3800 20F3800 10 Panel,Access, Filter 5F3701 5F3701 5F3701 12F3701 12F3701 12F3701 12F3701 11 Filter, CombustionAir R2014700 R2014700 R2014700 R2014700 R2014700 R2014700 R2014700
(1) (1) (1) (2) (2) (2) (2)
12 Panel, Enclosure, Pump 5C3015 5C3015 5C3015 5C3015 5C3015 5C3015 5C3015 13 Cover, Housing, Pump 5C3016 5C3016 5C3016 5C3016 5C3016 5C3016 5C3016 14 Cover, Pipe, Gas Manifold 5F3304 5F3304 10F3304 20F3304 20F3304 20F3304 20F3304
(2) (2) (2) (2) (2) (2) (2)
15 Plate, Cover, Sight 10338600 10338600 10338600 10338600 10338600 10338600 10338600 16 Bracket, Support, Pump Cover 5C3017 5C3017 5C3017 5C3017 5C3017 5C3017 5C3017
Internal Components - See Figure 24
17 Assembly, Base 5F1020 7F1020 10F1020 12F1020 15F1020 17F1020 20F1020 18 Panel, Front, Combustion Chamber 5F2003 7F2003 10F2003 12F2003 15F2003 17F2003 20F2003 19 Panel, Rear, Combustion Chamber 5F2006 7F2006 10F2006 12F2006 15F2006 17F2006 20F2006 20 Panel, Top, Combustion Chamber 5F2001 7F2001 10F2001 12F2001 15F2001 17F2001 20F2001 21 Weldment, Chamber, Left Side, Bottom 5C2602 5C2602 5C2602 5C2602 5C2602 5C2602 5C2602 22 Weldment, Chamber, Right Side. Bottom 5C2202 5C2202 5C2202 5C2202 5C2202 5C2202 5C2202 22A Panel, Chamber, Left/Right Side, Top 5C2002 5C2002 5C2002 5C2002 5C2002 5C2002 5C2002
(2) (2) (2) (2) (2) (2) (2)
23 Assembly, Sight Glass 10956000 10956000 10956000 10956000 10956000 10956000 10956000 24 Panel, Left Side,Air Box 5F2015 5F2015 5F2015 5F2015 5F2015 5F2015 5F2015 25 Panel, Right Side,Air Box 5F2016 5F2016 5F2016 5F2016 5F2016 5F2016 5F2016 26 Panel,Access,Air Box 5F2004 7F2004 10F2004 12F2004 15F2004 17F2004 20F2004 27 Cover,Access Panel,Air Box 5F2005 5F2005 5F2005 5F2005 5F2005 5F2005 5F2005
(1) (1) (1) (2) (2) (2) (2)
28 Divider, Chamber, Upper,Air Box 15F2005 15F2005 29 Divider, Chamber, Lower,Air Box 15F2002 15F2002 30 Divider, Front Chamber, Combustion Chamber 20F2002 20F2002 31 Assembly, Exhaust Stack 5F2027 7F2027 7F2027 12F2027 12F2027 12F2027 12F2027

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Item Description Size Size Size Size Size Size Size
500 750 1000 1250 1500 1750 2000
32 Assembly, Copper Tube, Heat Exchanger 5C4000 7C4000 10C4000 12C4000 15C4000 17C4000 20C4000
Assembly, Cupro-Nickel, Heat Exchanger 5C4020 7C4020 10C4020 12C4020 15C4020 17C4020 20C4020
33 Tile, Side (left and right) T2015600 T2015600 T2015600 T2015600 T2015600 T2015600 T2015600
(2) (2) (2) (2) (2) (2) (2)
34 Tile, Front T2017300 35 Tile, Front, Left Side T2016200 T2016800 T2016800 T2016800 T2016800 T2016800 T2016800 36 Tile, Front, Right Side T2016300 T2017100 T2017900 T2017100 T2017900 T2017100 37 Tile, Front, Center T2016900 T2016900 T2016900 T2016900
(1) (1) (2) (2)
38 Tile, Rear T2015700 39 Tile, Rear, Left Side T2017500 T2016600 T2016600 T2016600 T2016600 T2016600 40 Tile, Rear, Right Side T2016600 T2016600 T2018100 T2016600 T2018100 T2016600 41 Tile, Rear, Center T2017200 T2017200 T2017200 T2017200
(1) (1) (2) (2)
42 Tile, Bottom T2015500 43 Tile, Bottom, Left Side T2017400 T2017400 T2017400 T2017400 T2017400 T2017400 44 Tile, Bottom, Right Side T2016500 T2017400 T2018000 T2017400 T2018000 T2017400 45 Tile, Bottom, Center T2015900 T2015900 T2015900 T2015900
(1) (1) (2) (2)
Gas Train Components - See Figure 24
46 Blower R2060900 R2060900 R2060900 R2060900 R2060900 R2060900 R2060900
(1) (1) (1) (2) (2) (2) (2)
47 Weldment, Blower Mount 5C5300 5C5300 5C5300 5C5300 5C5300 5C5300 5C5300
(1) (1) (1) (2) (2) (2) (2)
48 Manifold, Gas Supply 5C6100 7C6100 10C6100 12C6100 15C6100 17C6100 20C6100 49 Valve, Ball, Manual Shutoff V2003100 V2003100 V2003200 V2003300 V2003300 V2003300 V2003300 50 Valve, Gas, Combination V2017600 V2017600 V2017600 V2017600 V2017600 V2017600 V2017600
(2) (3) (3) (5) (5) (6) (6)
O-Ring, Gas Valve V2017500 V2017500 V2017500 V2017500 V2017500 V2017500 V2017500
(4) (6) (6) (10) (10) (12) (12)
51 Weldment, Pipe, Gas Valve/Ball Valve P2047900 P2047900 P2047900 P2047900 P2047900 P2047900 P2047900
(2) (3) (3) (5) (5) (6) (6)
52 Valve, Ball, Manual Shutoff, Secondary V2000200 V2000200 V2000200 V2000200 V2000200 V2000200 V2000200
(2) (3) (3) (5) (5) (6) (6)
53 Manifold, 3 Burner/Orifice, Left L2012800 L2012800 L2012800 L2012800 L2012800
(1) (2) (3) (1) (2)
Manifold, 3 Burner/Orifice, Right L2012900 L2012900 L2012900 L2012900 L2012900
(1) (1) (2) (1) (1)

Mighty Therm2Page 35
Item Description Size Size Size Size Size Size Size
500 750 1000 1250 1500 1750 2000
Manifold, 4 Burner/Orifice, Left L2012600 L2012600 L2012600 L2012600
(2) (2) (2) (4)
Manifold, 4 Burner/Orifice, Right L2012700 L2012700 L2012700 L2012700
(1) (1) (1) (2)
54 Assembly, 3 Burner L2012200 L2012200 L2012200 L2012200 L2012200 L2012200
(2) (3) (5) (2) (3) (2)
Assembly, 4 Burner L2012500 L2012500 L2012500 L2012500
(3) (3) (3) (4)
55 Orifice, Gas, Natural L2013000 L2013000 L2013000 L2013000 L2013000 L2013000 L2013000
(6) (9) (12) (15) (18) (21) (24)
Orifice, Gas, Propane L2012400 L2012400 L2012400 L2012400 L2012400 L2012400 L2012400
(6) (9) (12) (15) (18) (21) (24)
56 Gasket, 3 Burner S2012700 S2012700 S2012700 S2012700 S2012700
(2) (3) (5) (2) (3)
Gasket, 4 Burner S2012500 S2012500 S2012500
(3) (3) (3)
57 Ignitor, Hot Surface w/Gasket 2400-286 2400-286 2400-286 2400-286 2400-286 2400-286 2400-286
(1) (1) (2) (2) (2) (2) (2)
Heat Exchanger Components - See Figure 25
58 Flow Switch RE0013000 RE0013000 RE0013000 RE0013000 RE0013000 RE0013000 RE0013000 59 Low Water Cutoff (optional) R0021901 R0021901 R0021901 R0021901 R0021901 R0021901 R0021901 60 Gauge, Temperature/Pressure RA0079000 RA0079000 RA0079000 RA0079000 RA0079000 RA0079000 RA0079000 62 Tee,Adapter, Outlet, Cast Iron 20130001 20130001 20130002 20130002 20130002 20130002 20130002
Tee,Adapter, Outlet, Cast Iron (boiler only) 20130009 20130009 Tee,Adapter, Outlet, Bronze 20150302 20150302 20150303 20150303 20150303 20150303 20150303
63 Relief Valve, Hydronic, 75 Psi A0063300 A0063300 A0063600 A0063600 A0063600 A0063600 A0002700
Relief Valve, Water Heater, 125 Psi RA0001200 RA0001200 RA0001200 RA0001200 A0064400 A0064400 A0064400
64 Flange, Connection, Cast Iron 10391302 10391302 10391303 10391303 10391303 10391303 10391303
Flange, Connection, Bronze R20255401 R20255401 R10391304 R10391304 R10391304 R10391304 R10391304
65 Gasket, Connection Flange S0063700 S0063700 S0063700 S0063700 S0063700 S0063700 S0063700
(2) (2) (2) (2) (2) (2) (2)
66 Cover, In/Out, Glass-Lined Cast Iron R10364504 R10364504 R10364504 R10364504 R10364504 R10364504 R10364504
Cover, In/Out, Bronze 10364501 10364501 10364501 10364501 10364501 10364501 10364501
67 Gasket, Header/Cover S0095100 S0095100 S0095100 S0095100 S0095100 S0095100 S0095100
(2) (2) (2) (2) (2) (2) (2)
68 Water Barrier, Inlet/Outlet 20230101 20230101 20230101 20230101 20230101 20230101 20230101 69 Baffle, Water Deflector, Inlet 10338300 10338300 10338300 10338300 10338300 10338300 10338300 70 Well, Immersion, Temperature Control RE2058300 RE2058300 RE2058300 RE2058300 RE2058300 RE2058300 RE2058300 71 Cover, Return, Glass-Lined Cast Iron 10364300 10364300 10364300 10364300 10364300 10364300 10364300

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Item Description Size Size Size Size Size Size Size
500 750 1000 1250 1500 1750 2000
NOTE: Quantityis one (1)unlessotherwise indicated.
Cover, Return, Bronze 10364301 10364301 10364301 10364301 10364301 10364301 10364301
72 Pump Housing, Glass-Lined Cast Iron R20607600 R20607600 R20607600 R20607600 R20607600 R20607600 R20607600 73 Baffle, Diffuser, Pump Housing Inlet 10338400 10338400 10338400 10338400 10338400 10338400 10338400
Electrical Components - See Figure 26
74 Control, Gas Ignition, Three Try (standard) E2313900 E2313900 E2313900 E2313900 E2313900 E2313900 E23
(1) (1) (2) (2) (2) (2) (2)
Control, Gas Ignition, Single Try (CSD-1 option) E2107300 E2107300 E2317300 E2317300 E2317300 E2317300 E2317300
(1) (1) (2) (2) (2) (2) (2)
75 Spdt, Toggle Switch E0109200 E0109200 E0109200 E0109200 E0109200 E0109200 E0109200 76 Terminal Block, 16 Position, Dual Row E2327500 E2327500 E2327500 E2327500 E2327500 E2327500 E2327500 77 High-Limit, Manual Reset, Hydronic Boiler, RE0015900 RE0015900 RE0015900 RE0015900 RE0015900 RE0015900 RE0015900
240°F Max. High-Limit, Manual Reset, Water Heater, E2217800 E2217800 E2217800 E2217800 E2217800 E2217800 E2217800 200°F Max.
78 Temp Control, 2 Stage, 130°F to 230°F RE0093200 RE0093200 RE0093200 RE0093200 RE0093200 RE0093200 RE0093200 79 Panel, Mounting, Limits/Ignition Control 5F7001 5F7001 5F7001 5F7001 5F7001 5F7001 5F7001 80 Panel, Cover, High Limit/Ignition Control 5F7003 5F7003 5F7003 5F7003 5F7003 5F7003 5F7003 81 Panel,Access, Terminal 5F7006 5F7006 5F7006 5F7006 5F7006 5F7006 5F7006 82 Switch, Rocker, 10A, 250 VAC, 1/2 HP,
15A, 125 VAC 1/2 HP E2322700 E2322700 E2322700 E2322700 E2322700 E2322700 E2322700
83 Terminal Block, 6 Position, Dual Row E2327700 E2327700 E2327700 E2327700 E2327700 E2327700 E2327700 84 Terminal Block, 12 Position, Dual Row E2327600 E2327600 E2327600 E2327600 E2327600 E2327600 E2327600 85 Switch, Pressure, Diaphragm, Spdt RE0240900 RE0240900 RE0240900 RE0240900 RE0240900 RE0240900 RE0240900
(2) (2) (2) (3) (3) (3) (3)
86 Bracket, Pressure Switch 5F7007 5F7007 5F7007 5F7007 5F7007 5F7007 5F7007 87 Transformer, 150 VA, 120/24V E2312800 E2312800 E2312800 E2312800 E2312800 E2312800 E2312800 88 Relay, Time Delay (24 VAC) RE2077700 RE2077700 RE2077700 RE2077700 RE2077700 RE2077700 RE2077700
Delay on Break,Adj.
89 Relay, 120VAC, DPDT E2328000 E2328000 E2328000 E2328000
(2) (2) (2) (2)
Relay, 24VAC, DPDT E2327800 E2327800
90 Panel, Mounting, LWCO Switch (optional) 5F7005 5F7005 5F7005 5F7005 5F7005 5F7005 5F7005 91 Wire Harness #1, Fenwal E2328800 E2328800 E2328400 E2328400 E2328400 E2328400 E2328400 92 Wire Harness #2, Control Panel E2328900 E2328900 E2328500 E2328500 E2328500 E2328500 E2328500 93 Wire Harness #3, Main E2329000 E2329000 E2329100 E2328600 E2328600 E2328600 E2328600 94 Wire Harness #4, Local Remote SW E2328700 E2328700 E2328700 E2328700 E2328700 E2328700 E2328700

Mighty Therm2Page 37
Figure 23. Sheet Metal Components.

LAARS Heating Systems
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Figure 24. Internal Components

Mighty Therm2Page 39
Figure 25. Heat Exchanger Components.
Mighty Therm2 Hydronic Boiler
Size Pump p/n
500 A2001700
750 A2001700
1000 A2001800
1250 A2001800
1500 A2001900
1750 A2001900
2000 A2109700
Mighty Therm2 Water Heater
Size Pump p/n
Soft Water Normal Water Hard Water
500 A2001700 A2001700 A2001900
750 A2001700 A2001700 A2001900
1000 A2001700 A2001800 A2001900
1250 A2001700 A2001800 A2001900
1500 A2001700 A2001900 A2001900
1750 A2001900 A2001900 A2001900
2000 A2109700 A2109700 A2109700

LAARS Heating Systems
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Figure 26. Electrical Components.
800.900.9276 • Fax [phone] (Customer Service, Service Advisors)
20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax [phone] (Applications Engineering)
1869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 • 905.238.0100 • Fax [phone]
www.Laars.com Litho in U.S.A. © Laars Heating Systems 0807 Document 1211