EFFICIENCY BOILERS - WATER HEATERS WIRING DIAGRAMS - LADDER DIAGRAM – WATER HEATER MODELS 150,000-300,000 BTU / HR

Oct 26, 2026

Ladder wiring diagrams for efficiency boiler and water heater systems covering water heater models rated 150,000–300,000 BTU/hr. Content specifies connections to 120 VAC power supply, power switch, transformer outputs, thermostat and limit switches, gas valve, blower, pump, LWCO and flow/low-air proving switches, ignition module and igniter transformer. Includes wiring notes such as removing jumpers between W1/R1 and X/B, terminal board labeling, relay/alarm contact wiring, and optional equipment such as pump delay and freeze protection.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

Wiring Diagram Overview

Water Heater Ladder Diagram (150,000–300,000 BTU/hr)

Boiler Ladder Diagram (150,000–300,000 BTU/hr)

Wiring Notes and Optional Equipment

EB-EW-WRG-01 EFFICIENCY BOILERS / WATER HEATERS WIRING DIAGRAMS LADDER DIAGRAM – WATER HEATER MODELS 150,000-300,000 BTU / HR TO 120 VAC POWER SUPPLY OPTIONAL EQU IPMENT W IRING |
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COMBUSTION
IGN MOD P5 AIR BLOWER | |
IGNITER | | 120 VAC | POWER SWITCH OFF ON TRANSFORMER 24 VAC THERMOSTAT CN 7 CN 8 24VDC PUMP DELAY LIMIT * LWCO MRHL SWITCH R1 W1 CN 1-4 CN 1-3 R2 W2 * HFGV C NO NC C NO NC GAS VALVE * RELAY (ALARM) * ALARM CONTACTS TDR * LOUVER CONTACTS | P 3-2
P 3-3
P 3-6 | IGNITION MODULE | P 3-8
P 3-5 | | --- | --- | --- | * FLOWSWITCH X B P 3-7 | LOW AIR | | | | --- | --- | --- | | P 3-1 | | | L1 (HOT) L2 * LWCO 6 2 CN 2-1 CN 2-2 ALARM BELL WIRING DIAGRAM – WATER HEATER MODELS 150,000-300,000 BTU / HR * * PROBE 2 1 C | | | | --- | --- | DISCONNECT POWER BEFORE SERVICING UNIT BL BL INLET TANK IF NOT EQUIPPED SENSOR SENSOR WITH LWCO CONNECT TO "R1" . ELSE OR CONNECT TO * WIRING NOTES: LWCO "COM" . 1. REMOVE JUMPER BETWEEN “W1” AND “R1” TO CONNECT C NO REMOTE OPERATOR OR MOD-U-PAK . P FLOW 2. WIRE ALL PROVING SWITCHES, FLOW SWITCHES, AND CONTROLS TO BK SWITCH “X” & “B” IN SERIES TO SCREW TERM INALS . BK NOTE: REMOVE JUMPER BETWEEN "X" & "B" . T BL OR TERMINAL BL STRIP *ALARM R1 W1 R2 W2 A X B C * OPT. AMRHL OPT IONAL AMRHL REQUIRES MAX STOP SET @ 240°F 2 2 1 (+) OPT. FMRHL 1 BL/W * LOUVER 24V RELAY CONTACTS 1 3 2 24V RELAY 4 5 6 R R Y TERMINAL BOARD OR R/BK T THERMOSTAT Y LIMIT BL Y R/ORR/W IF NO H IGH FIRE GAS VALVE R/W Y BL/W R/W OR R/BK R/BK OR OR WIRES TIED OFF & CAPPED 8 1 7-C 2-C 6-NO 3-NO 5-NC 4-NC T IME DELAY RELAY * ALARM BR BR CONTACTS BL Y IGN IT ION TRANSFORMER MODULE BK W GY IGNITERGY BURNER GROUND WATER HEATER LBL200 17 REV A R/BK BL Y GY GY BR W GR BK W H IGH FIRE GAS VALVE R/BK C NC NO LOW AIR SWITCH Y OR/RY WIRES TIED OFF & CAPPED BL T R Y Y IF NOT EQUIPPED Y WITH LWCO GAS VALVE BR W GR BLOWER BK/W W PUMP W SPLICE 5 BL BL Y BK/W BL ALARM BELL * BR J3 OR T 6 3 5 2 4 1 PR BL/BK OR OR PUMP DELAY/ FREEZE PROTECTION C NO 24 VDC TEST BUTTON T O . C . 24 V BL Y LWCORESET J2 24 VAC T ON-OFF SWITCH 1 2 3 BL BL J4 OR GR 1 2 3 GNDP G PR PR RESET RESET WBK W GR * IF EQUIPPED OPTIONAL EQU IPMENT WIRING USE ELECTR ICAL CONNECTION 1& 2 (+) J1 2 of 4 LADDER DIAGRAM – BOILER MODELS 150,000-300,000 BTU / HR OPTIONAL EQU IPMENT W IRING * IF EQUIPPED BOILER LBL200 18 REV A TO 120 VAC POWER SUPPLY POWER SWITCH OFF ON A IGN MOD P5 IGN MOD P6 * PUMP DELAY 24V PUMP RELAY COMBUSTION AIR BLOWER IGNITER * PUMP 120 VAC 24 VAC TRANSFORMER * LWCO A R1 W1 MRHL THERMOSTAT CN 7 CN 8 24VDC PUMP DELAY 24VAC PUMP RELAY CN 1-1 CN 1-4 CN 1-2 CN 1-3 LIMIT SWITCH R2 W2 * FLOWSWITCH LOW AIR X B P 3-7 P 3-1 P 3-2 P 3-8 * HFGV P 3-3 P 3-6 IGNITION MODULE P 3-5 C NO NC C NO NC GAS VALVE * RELAY (ALARM) * ALARM CONTACTS TDR * LOUVER CONTACTS * LWCO 6 2 CN 2-1 CN 2-2 ALARM BELL 3 of 4 WIRING DIAGRAM – BOILER MODELS 150,000-300,000 BTU / HR REV A DISCONNECT POWER BEFORE SERVICING UNIT * PROBE | | | | --- | --- | OR WIRING NOTES: 1. REMOVE JUMPER BETWEEN “W1” AND “R1” TO CONNECT REMOTE OPERATOR OR MOD-U-PAK . 2. WIRE ALL PROV ING SWITCHES, FLOW SWITCHES, AND CONTROLS TO“X” & “B” IN SERIES TO SCREW TERM INALS . 3. PUMP DELAY OPERATION IS OPTIONAL WITH KIT3058. BL BL * NO CP FLOWSWITCH NOTE: REMOVE JUMPER BETWEEN "X" & "B" . IF NOT EQUIPPED WITH LWCO CONNECT TO "R 1" . ELSE CONNECT TO LWCO "COM" . * INLET SYSTEM SENSOR SENSOR BK BK * OPT. AMRHL BL/W 2 2

FAQs

What power supply voltage is used in these wiring diagrams?

The diagrams show connection to a 120 VAC power supply, feeding a transformer that provides 24 VAC and 24 VDC-related signals for control components.

Which jumper connections are referenced in the wiring notes?

The notes specify removing the jumper between W1 and R1 to connect a remote operator or MOD-U-PAK, and removing the jumper between X and B for proper series wiring.

What components are shown as part of the ignition and safety control system?

The diagrams include an ignition module and igniter/ignition transformer, a gas valve, LWCO-related wiring, flow/low air proving switch contacts, and alarm bell/relay contacts tied to control signaling.

Oct 26, 2026

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