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Transformer problem/Dayton 350k btu nat gas heater

2788 Views 3 Replies 2 Participants Last post by  George.hicks
MY wife has greenhouses...(that in itself should make you cringe) Installed a 350k btu Dayton heater 5 years ago. Heater worked flawlessly for about 3 years, this thing developed a transformer issue (step down transformer for the thermostat circuit) It had a White Rodgers trans with a 3ma breaker switch on it. Started tripping the breaker. Intermittent, no apparent reason...109v-122v variance at the heater, 30 amp breaker at the power panel.

Replaced the White Rodgers with a matching spec transformer w/o the breaker (thinking the breaker might be weak) 2nd trans lasted about a week, blew the secondary side (24v ac) put another trans in place (3rd) Wednesday evening and this morning the secondary side is blown....I put the old White Rodgers back in place this morning, came to life as soon as I plugged the heater back in......Can anyone point me in a direction to diagnose this issue??? Anyone seen it before??
Only thing I can figure is feedback/short, but from where??
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You have a short on the secondary side of the transformer. Check all the low voltage wires.
You have a short on the secondary side of the transformer. Check all the low voltage wires.
thanks for the response George...if it was a dead short the heater wouldn't come on at all....what else would cause a short on the low voltage side of the circuit???
Looking for short

I would first visualy inspect all of the wires for anything that might be melted or rubbing against something.
If I do not find anything I will remove the thermostat connections at the heater and try to run the unit with jumpers.
Next I will jumper between R and W and see if it runs
If the low voltage breaker trips, make a note at what part of the start sequence it trips at.
If everything runs great, then it is in the thermostat control circuit.
If you still can not figure it out, try disconnecting one low voltage device at a time and see if you can locate it that way.
Shorts a sometimes difficult to find, but if you stick to it you will find it.
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