no heat downstair, but upstairs good, gas boiler, baseboard heat. themos fine


Old 04-03-14, 12:48 PM
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no heat downstair, but upstairs good, gas boiler, baseboard heat. themos fine


Have a Weil-McLain Gas Boiler CGi cast iron boiler with 3 zone baseboard heat, 3 separate thermostats and Honeywell zone valves (similar to V8043). The system was working fine for a year.

Now a problem: Zone 1 upstairs works fine (has separate thermostat gas boiler turns on and heats fine. Zone 2 and 3 downstairs with separate themostats turn on, but gas boiler does not ignite. I switched all thermostats and they are all working fine, The valves move when I call for heat for Zone 2 and Zone 3, looks like the flu opens, but boiler never ignites. It ignites when I put upstairs Zone 1 on (and I can heat up downstairs like that) but wanted to solve the problem.

I think the thermos work, zone valves work, good pressure in system. Problem lies with no ignite for Zone 2 and 3 but ignites for Zone 1.

What parts should I buy or replace (should I jump wires). Thanks.
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Old 04-03-14, 01:09 PM
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Honeywell zone valves (similar to V8043).
Similar or not, we would like to know what they ARE, please post the model number of the zone valves.

A thermostat can work and open the zone valve, but the 'endswitch' in the zone valve that tells the boiler to fire can be bad and the boiler won't fire.
Old 04-03-14, 01:15 PM
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Your zone valve has 4 terminals. Two wires come from the t-stat and open the valve, the other two go to the boiler to fire it up on a call for heat. Since they open your t-stat circuit is fine. Find the point where the two wires from each valve go to TT on the boiler. It will be the same location that zone 1 is tied into.
You may just have a loose connection.

I doubt if it's serious since Z1 is working and 2 & 3 have the same issue. If you find the bad connection you'll find the problem. Redo the wires if that's the case and you'll be fine.

Good Luck,

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