My A/C stoped working two days ago. I would really appreciate some help trouble shooting if someone has the time. My HVAC contractor is away and we are sweltering in CT right now. I am a remodeling contractor so I probably have just enough knowledge to get myself in some real trouble. Here are the details.
A/C or heat will not come on. Fan will not come on when t stat is calling. Fan will come on manually by using the switch on the fan limit control. Existing system is oil fired warm air / A/C two zone with a Mastertrol Mark V control panel with remote selector switch. On the phone with my HVAC contractor we thought that the problem was in the selector switch or the panel. Honeywell tech support told me how to jump out the selector switch to get fan and cooling, fan came on but not compressor which led us to believe that a problem in the panel burned out the switch or vica versa.
First tried new transformer.
Installed new honeywell EMM-3U control panel. Went over the wiring with honeywell tech support before powering it up. Still no good. No fan, no compressor, no heat.
The panel has a thermal overload so I wasn’t too scared to try a few things.
The instructions say with oil heat to remove the Rc Rh jumper but then says for all single stage conventional to leave it on, I tried it both ways N/G.
Is it correct that the fourth (G to G) wire from the t stat is only necessary for manual fan control. presently I only have three wires. My thinking is that manual fan operation should not affect the heating or cooling controls.
I shut down the zone two t stat and tried the fourth wire on zone 1 with no luck.
The compressor does have power and I can make it run by engaging the contacts.
between the fan limit switch and the oil burner primary there is a relay, could that be the problem.
If anyone has any thoughts they would be appreciated. Thanks.
Edited 6/27/2005 8:08 pm ET by des
Replies
des,
Does your system have a condensate pump ? If so, is it full or not pumping ? Ours has a safety on the pump so that if the pump fails and its little reservoir gets full, the system will not work.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
good thought, I replaced my condensate pump last year and when I found out that they had a model with that feature I could not believe that it is not a code requirement. Such a simple thing that can prevent a big mess. However, even though i thought it was a great idea I have yet to wire it in. The cobbler's son. . .
you got ants in the outside relay. the ants are stoping the relay from clicking, common problem. contact cleaner.
The contacts are clean and that would not be my no heat problem.