Weil-McLain GOLD DV WATER BOILER, 550-141-850/0599 manual Chart 3 Limit & Power lights flashing

GOLD GV Water boiler series 3 — manual

XIg Troubleshooting — GCM lights (continued)

CHART 3 — LIMIT & POWER lights flashing

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

•This is a lockout condition. The return water temperature sensor has signaled a temperature higher than 240 ˚F, but the boiler limit circuit is closed (indicating that the limit

control circuit did not catch the over-temperature condition). This is probably an indication of a failure of the boiler limit control and possibly the block temperature switch as well.

•▲ TURN OFF POWER▲ to boiler at 120 VAC service switch.

•Remove CONTROL CIRCUIT plug from control module receptacle (Figure 34, Item 5).

•Remove a wire from one of the limit control spade connectors.

•Connect an ohmmeter across the left and right pins on the center row of the limit circuit harness.

Does the ohmmeter indicate a shorted wire harness (zero ohms)?

Yes

No

•Replace control wiring harness.

•Retest.

•Replace water temp sensor.

•Retest.

•Reconnect CONTROL CIRCUIT plug to control module.

•Remove WATER TEMP SENSOR plug from control module receptacle (Figure 34, Item 6).

•Connector an ohmmeter across the plug pins to check the sensor resistance.

Does the ohmmeter indicate a shorted sensor (zero ohms)?

Yes		No
	Is boiler hot?
Yes		No

•Close the external manual gas valve.

•Remove one wire from the limit control space connector.

•Set a thermostat to call for heat. Then turn on power to the boiler at the 120 VAC service switch.

•The boiler system circulator should come on and the control module should try to cycle the boiler.

•Allow the boiler circulator to run to cool off boiler and system water.

•After the boiler and system water have cooled, turn off power at the 120 VAC service switch and open the external manual gas valve.

•Set limit control knob to its minimum setting. Replace wire to limit control spade connector.

•Set a thermostat to call for heat.

•Turn on power at 120 VAC service switch.

•Control module should cycle boiler on and begin heating. • The limit control should shut off the gas valve when the

temperature at the boiler pressure/temperature gauge has reached no more than about 20 ˚F higher than the limit switch setting.

Does limit control shut off gas correctly?

	Yes		No
•	Replace control	•	Replace limit control
			and block tempera-
	module.
			ture switch.
•	Retest.
		•	Retest.

76 Part number 550-141-850/0699