• Installation • Start-Up • Parts • Maintenance

CHART 6 TSTAT CIRC light flashing and POWER light on steady

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 not a lockout mode. The control module is signaling that the return water temperature sensor is detecting a temperature less than 40 ˚F.

While the temperature at the boiler return water temperaure sensor is less than 40 ˚F, both of the internal boiler circulators will run continuously, even if there is no call for heat (though the boiler will not fire until the thermostat calls for heat). This operation is intended to reduce chances of freezing during system down times by keeping water flowing.

 

 

 

 

 

 

 

Is return water temperature sensor clamped

 

 

 

 

Attach sensor to pipe

 

 

 

 

securely to the return pipe in the boiler?

 

 

 

 

 

with clamp provided.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No

 

 

 

Yes

 

 

 

 

If problem persists,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

replace return water

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

temperature sensor.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Retest.

 

 

 

 

 

 

 

 

 

 

Are both boiler internal circulators operating?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No

 

 

Yes

• Remove CIRCULATORS plug (Figure 34, Item 4) from

 

 

 

 

 

 

 

 

 

 

 

plug receptacle of control module.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• Place voltmeter leads across the 120 VAC N and

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

120 VAC H pins of the CIRCULATORS receptacle on the

 

 

 

 

 

 

Is there a call for heat?

 

side corresponding to the circulator not operating.

 

 

 

(Verify by removing thermostat wirings at boiler and

 

Does the voltmeter indicate 120 VAC?

 

 

 

checking continuity across external wires)

 

 

 

 

 

No

 

 

Yes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No

 

 

Yes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Replace GCM (control module).

Retest.

Replace circulator harness.

Retest.

Test wire continuity of circulator wire harness.

Is harness ok?

 

No

Yes

 

 

 

 

 

 

 

 

 

 

This is normal operation for water less than 40 ˚F at boiler internal return pipe.

Condition should change after a call for heat, when the boiler will heat up the water.

Wait 10 minutes to allow heat from the boiler to raise the water temperature.

Does LIMIT light quit

flashing (and pipes begin

to heat up)?

No

Yes

 

 

Reconnect circulator harness to GCM.

Attempt to get the circulator started by giving it a sharp rap on the end of the circulator motor (to release a possibly locked impeller).

If the circulator begins to operate, allow it to operate for a few minutes to see if the problem clears.

If problem persists, replace the bypass circulator.

Retest.

• Boiler is not heating.

• Troubleshoot boiler using CHART 8.

Boiler should now operate normally.

Verify correct sequence of operation using Figure 22.

Part number 550-141-850/0699

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Weil-McLain 550-141-850/0599, GOLD DV WATER BOILER manual Chart 6 Tstat Circ light flashing and Power light on steady