It's a 24volt gas control valve. Themocouple for the pilot and
diaphragm valve for the main burner. The transformer reads 29volts and
I read 27 volts across the diaphragm valve activator(stat closed) and
20 ohms. I noticed that someone has been using a candle to light pilot
and there is wax all over the bleeder tube. I tried to unscrew bleeder
tube from the valve unit but it did not come out easily and came out
crooked so i decided to screw it back in and seal with wax. I was
thinking of cutting the tube instead and blowing compressed air
through to see if it is blocked.(i'm a good solderer). If bleeder tube
is not blocked i was going to replace gas control valve. Comments.
The bleeder tube was not plugged. If it is not the diaphragm valve,
what could it be? the pilot light is fine. No gas goes to main burners
when stat on. Diaphragm valve is receiving voltage. I assume gas
pressure is ok because pilot light and water heater are working.
Incidently, how would you clean a bleeder tube?
I posted some pics of the furnace and gas control at the following
Looking at those pics, honestly, I would get someone in that either has a
tool called the Inspector, or similar.
HAve them check the heat exchanger ASAP.
Now, the valves got voltage, but is the voltage completing its trip? Your
gas valve is wired through the fan limit switch, and prob at least one
overload. Check em.
Those valves were rare to go bad, but after 30 years, its possible, but it
would be rare.
Ok, I'll get someone to inspect the furnace for safety. What do you
completing it's trip? Do you mean that it keeps resetting itself so I
don't notice? Because the voltage is 27v continuous. What is the
purpose of the fan limit switch? If the fan does not come on in a set
time does it shutoff the gas? I bypassed the fan limit switch and
still did not get gas to burners.
Thanks for indulging me.
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