Coleman evcon eb20b no heat or /ac

handyman555

I have a coleman evcon eb20b and all the sudden no heat or ac

i looked at tstat (honeywell chronotherm III) and no lights are on but cant remember if they only came on when in operation.

things ive done

replaced batteries in t-stat

checked fan ,heat and ac by crossing red and green, red and white etc and got nothing

tested for 24v at t-stat red and blue (common) nothing (checked all wires actually)

opened up heater traced where red and blue wires connect to other wires took off wirenuts ant tested there and nothing

what do i check next transformer? if so what peg or pegs to i check ... i got 240 going in but which ones for 24v out?

thanks for you help

handyman555

Doc Holliday

The wires on the other side of the 240 (120?) going into the transformer going out will be 24 out. It should state on the transformer which wires are 24 volts.

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Thanks.

Mr.HVAC

since you are not getting 24v from R and C, your board doesn't have power. Test transformer like Doc said above, also while you are there check the 3 amp fuse, make sure it's good. Actually did you check to make sure you have 120v going into the furnace? Try to plug a light into the furnace's outlet to see if you have power

beenthere

On Evcons usually a red and black coming off the transformer for your 24 volts. The red on some have a 3 amp fuse. Depends on when it was made.

handyman555

it looks like i am getting nothing on the side that says load (red and blk wires) i am getting 247v on line side of transformer and getting 247 or 123v every other way .... also have no plug in to test on my coleman unit

thanks again guys

beenthere

Might want to look for a short before you just put another transformer in it.

handyman555

it looks like i got 240 v going in just not 24 comming out.....look for short where?... shouldnt there be 24v comming out of the load side of transformer sorry im a carpenter not an electrician so bare with me

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Doc Holliday

If you do not have 24-ish volts coming out than the transformer is 100% kapoOt.

Be forewarned, once in a blue moon Pale Ale , a transformer will simply go out. 9 of 10 times an electrical issue such as a backfeed or short somewhere caused the transformer to blow. You will know once you install a new transformer.

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Thanks.

Doc Holliday

Check all control wiring to see if anything anywhere has lost it's insulation and is touching metal cabinet or another wire.

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Thanks.

handyman555

I bought a transformer with built in fuse so if there is short it won't blow my transformer .. There is no fuse on this unit... Will check all wires tho

Thanks again

Doc Holliday

Good choice! If there is no fuse than it's going to be a short on the low voltage side, such as beenthere previously said. Had it been on the high voltage lines the breaker(s) would have tripped in your home's electrical service panel, most likely.

Let us know if the fuse blows and on what call, fan on , heat or cool. Actually, best bet would be to try heat first and then fan on. If your transformer blew while on call for cool than it could be outside at the condenser.

Check cooling last.

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Thanks.

handyman555

that seemed to do the trick .. just a bad Transformer... i want to thank Doc Holliday,Beenthere and MR.HVAC for all your help... couldnt have done it with out you!!

what a great forum!

thanks again
Handyman555