intertherm mac 1265

[vatter]

We have had to replace the thermocoupling in our furnace at least once a year since we moved here 13 yrs ago but I don't know if that has anything to do with my current problem or not....
We replaced the thermocoupling and in the process a wire slipped and shorted out the thermostat so I replaced that with a new one also. I also replace the elcectronic burner contro after consulting a local heating guy.
Now when I light the pilot light the burn kicks on and works through one cycle. When the burn goes out so does the pilot light. Relight it and it will work for another cycle.
I've got 26 volts for thremostat control and burner control. There is 119 volts going to the burner motor but something not allowing it to room but with I hotwire it the motor works.
I can't figure this out....any ideas??
Thanks in advance.
Paul

[vatter]

Update:
I decided to fire it up after it has been off for several days to get the chill off the house....we have been using space heaters....and it is getting even weirder...
Lit the pilot light and the furnace ran for maybe 2 minutes with the thermostat set at 80....and then it shut off. I was getting ready to re light the pilot light to give it another go and then the heat box cooling fan came on....
It is like things are working backwards....
Now I am really confused!!

[Robert]

Hi,

You'll need an hvac tech for best resolution here. Probably shorted out low voltage circuitry.


Thanks,
Robert

[vatter]

Can you tell me what other low voltage items there are since I have already replaced the electronic burner control module....I have to try to find this on my own since I have called every HVAC in my area and none of them will work on one this old.....grrrrr

[Robert]

Hi,

It's because gas furnaces that old are dangerous and very hard to find parts for.

I don't have a wiring diagram for it, which you'll need to trace low voltage circuit.

Your t-stat, any relays or limits, gas valve, etc..... Most are in low voltage circuit IF it is a 24vac system.



Thanks,
Robert

[vatter]

I just need this one to hold out for 2 more months and the new house we r having built will be finished and this mobile home is being scrapped...hopefully I can figure it out.....

[Robert]

Hope it works out for you all.


Take care and best wishes,
Robert