Weil-McLain 550-110-260/02002 Boiler Manual, continued, Is boiler System circulator operating?

Boiler Manual

continued

CHART 7 — Insufficient heat or no heat to system (POWER light on steady)

Electrical shock hazard — Wherever you see ▲TURN OFF POWER▲, follow the instructions. Failure to follow instructions could result in severe personal injury, death or substantial property damage.

• Has it been at least 5 minutes since setting thermostat to call for heat? If not, wait 5 minutes. Is system heating?

• Is thermostat set to call for heat? Remove thermostat wires at boiler and check continuity across the two wires. If circuit isn't closed, check external thermostat (zone valve, relay, etc.) wiring. Correct problems and retry.

• Reconnect external thermostat wiring at boiler.

Is thermostat circuit closed (continuity across wires)?

No Yes

Is boiler System circulator operating?

No Yes

•Remove CIRCULATOR harness plug from CIRCULATOR plug receptacle (Figure 25, Item 7, page 44). Check with voltmeter across pins of control module receptacle.

Does voltmeter show 120 VAC across pins?

No Yes

Are all red lights off?

No Yes

Wait 30 seconds. Are all red lights off?

No Yes

Replace control module. Retest.

•Boiler is in standby.

•Set thermostat to call for heat and recheck

operation.

•Verify Sequence of operation, Figure 18, page 31.

•	Replace control	•	Repair/replace
	module.		circulator. Retest.
•	Retest.	•	Repair/replace
			wiring. Retest.

• Wait 5 minutes.

Is FLAME light on?

Yes No

• If you have sufficient heat — boiler should be in normal

Is LIMIT light on?

operating sequence. (See normal sequence of

operation, Figure 18.)

No

Yes

• If you have less than sufficient heat —

Is vent or combustion air piping free of blockage?

•

Check limit switch

•

Replace control module.

No

Yes

contacts with continuity

•

Retest.

checker.

•

Correct conditions and

Contact your Weil-McLain

Are limit switch contacts

recheck operation.

sales representative.

closed?

Check rollout switch

• See Figure 18, page 31

No

Yes

for normal sequence of

continuity — is switch

operation.

closed?

No

Yes

• Wait for boiler water to cool to temperature 20 to 30 ˚F

lower than temperature set on limit switch.

Are limit switch contacts closed?

•

Replace rollout switch.

No

Yes

•

Check any other

• Boiler water temperature exceeded

If rollout thermal fuse element has

limit controls wired

setting on limit switch with thermostat

opened, determine cause and

into the limit

•

Replace

calling for heat. Boiler is OK. (See normal

correct condition. Failure to do so

circuit. If all are

sequence of operation, Figure 18, p. 31.)

will cause severe personal injury,

OK, then replace

limit switch.

• Also check setting on limit switch (should

death or substantial property

control module.

•

Retest.

be above 140˚F.).

damage.

•

Retest.

Part number 550-110-260/0200

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