William gas wall heater- screw thermostat connection issue

Old 01-31-23, 11:04 AM
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William gas wall heater- screw thermostat connection issue

I'm having an issue with my 1 1/2 year old william gas wall heater. Sometimes it doesn't turn on because there's some connection issue between the thermostat and the connection point on the unit.

I can get it to work, when I use a screw driver and put some pressure on the screw highlighted in yellow. It has been tightened in the past and it can't be tightened anymore. I tried stripping the wire and wrapped it around the screw and retighten. Is there a loose connection internally? Anybody encounter this?

Old 01-31-23, 03:33 PM
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Does your heater have a standing pilot light?

If so disconnect the wires from the thermopile (they are labeled "generator"). Measure the voltage across the conductors. If it's below 400 millivolt make sure the pilot flame is good and properly aimed. Also make sure the flame is properly hitting the thermopile. If the voltage is still low replace the thermopile. They are a wear item so they do die with old age, though 1 1/2 years seems sooner than it should so I'm betting on a bad electrical connection.

A millivolt system operates at very low voltage. It doesn't take much to stop that tiny voltage and cause a connection problem A loose screw or slight bit of oxidation on the wire can stop it from working. You mentioned the screw on the gas valve but you also need to check all the other connections in the circuit like the thermostat.
Old 01-31-23, 04:36 PM
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It could be a defective gas valve.
Try this first... take a piece of wire and touch it from the center terminal (Th-Tr) to the highlighted yellow terminal. Don't push hard onto the valve. We want to see if it's a mechanical problem or low voltage. Does that bring the burner on ?

If not... you'll need a meter to check like Dane mentioned.
We want to make sure it's a valve problem... not associated wiring.
Unfortunately there is only a one year warranty on the gas valve.

The yellow arrow is pointing to the soldered coil connection.
I have had to resolder valves there in the past.
See if you can see a problem solder connection there.
It's a wire soldered to that terminal.

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