Rheem A/C Unit with a standard energy saver thermostat…As usual, I turn the thermostat to A/C and begin my upstairs inspection… Soon discovering that there’s no air being delivered, I go back to the thermostat and turn it to Fan/On.
Still nothing…Then I turn it to Heat-Fan/On, and it runs properly…
At the end of the inspection, I try the A/C again and it still wont activate the blower…
My Agent calls an HVAC friend who suggests that we hit the reset on the Fan/Limit switch. We did and it worked…The fan ran…
Now, as usual, I don’t remember the sequence of the changes I made to the thermostat. Could I have tripped a sensor to stop the fan from activating on demand? Or…is the problem with the Thermostat or Fan/Limit switch?
p.s. The furnace just happened to have a used Fan/Limit device laying on the ductwork…
I’d hate to write up an Inspector Operator Error…again…
Thanks, Bill
Bill simply put the HVAC system did not operate using normal switch actions. Don’t over think it. State it and give it to the AC guy.
It may have been a high or low head pressure error at the condensing unit, i sometimes run into this problem at work and I have to reset the condensing unit by pressing a button by the compressor. (need gauges to be positive) I have also had a CU fan motor go bad and the air handler was just circulating hot air. This is at a nursing facility though not a residence.
Being told now that the furnace had a bad ground and needed a new transformer…
Thanks Russell!
Exactly.
When was the last time you saw a thermostat with the manufacturers operating instructions, or special instructions i.e. “Do this, don’t do that”, posted above it?
Don’t think so…
What does this have to do with the indoor blower operation?
Nothing really, in this specific situation, just trying to provide some insight into some issues I have come across/ troubleshooting I have to deal with. Mr. Anderson what do you think the case may be? I agree that it probably was not a bad ground and transformer. Could have been the transformer, if it were truly “bad”, but wouldn’t that have needed to be replaced before the indoor squirrel cage would operate? Re-reading the OP, it kind of sounds like a delay or something similar. Or even worse a combination of several factors; delay, transformer,wiring, etc… What is your opinion?
The fan limit switch tripps from overheated heat exchanger.
Bad fan controller.
This is concerning the heat mode. Not working in the cooling mode is something else, maby the thermostat.
The green wire controls the fan in cooling, white circuit goes through the fan controller in heat mode.