Weil-McLain 550-110-710/0107 manual 11c Troubleshooting — control module lights cont

Models: 550-110-710/0107

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11c Troubleshooting — control module lights (cont.)

GOLD CGi Gas-Fired Water Boiler — Boiler Manual

11c Troubleshooting — control module lights (cont.)

CHART 2 TSTAT CIRC & POWER lights flashing

— Usually indicates 48 VAC on thermostat circuit (stray voltage) —

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.

Disconnect the two external wires connected to the boiler thermostat leads (two black low voltage leads in J-box).

Connect a voltmeter across these two incoming wires. Close each thermostat, zone valve and relay in the external circuit one at a time and check the voltmeter reading across the wires.

There should NEVER be a voltage reading.

If a voltage does occur under any condition, check and correct the external wiring. (This is a common problem when using 3-wire zone valves.)

Once the external thermostat circuit wiring is checked and corrected if necessary, reconnect the external thermostat circuit wires to the boiler thermostat wires and allow the boiler to cycle.

Did you find a voltage across the two external thermostat circuit wires?

Yes

No

Leave external boiler thermostat connection wires disconnected from boiler.

Troubleshoot the external thermostat circuit until you find the source of the stray voltage. (Pay close attention to the wiring connections to 3-wire zone valves.)

Correct the problem and repeat the voltmeter test above, verifying there is no longer a voltage reading under any condition in the external thermostat circuit.

An isolating relay may be required.

If no voltage is found under any condition of the external thermostat circuit, connect the two boiler thermostat connection leads together (or jumper the boiler aquastat T-T terminals).

• Turn off power to the boiler for 1 minute.

• Turn on power and allow boiler to cycle.

Do the TSTAT and POWER lights still flash?

No

 

Yes

 

 

 

 

Boiler should now operate per the normal sequence of operation shown in Figure 30, page 37.

Replace control module.

Retest.

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Part Number 550-110-710/0107

 

Page 52
Image 52
Weil-McLain 550-110-710/0107 11c Troubleshooting — control module lights cont, Do the TSTAT and POWER lights still flash?