AboutHoward Livingston Expertise Can answer questions on electrical control circuits, power supply,airflow & distribution, electrical components,refrigerant problems,gas, electric & propane furnaces.No boiler or refrigerator or oil fired furnaces experience.Just HVAC questions please.
Experience 35 years experience in residential & light commercial repair & installation.
Question QUESTION: Howard,
I have a 1991 Rheem 2.5 ton all electric heat pump system. In cool mode, the indoor motor does not run occasionally. The outdoor unit works fine. When the indoor fan doesn't work, I turn off all the power and then turn it back on and it will run again until it decides not to cycle on. The run capacitor works fine. The motor sounds fine when it works.
ANSWER: In cool mode & fan in auto, the thermostat turns on the fan. If you have a digital tstat, have had reports like yours. Not good without inside fan. Try turning off power to the outside unit, then repeatedly cycle the cool off & on(fan in auto) & see if you can catch it for a test of the tstat.
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QUESTION: I have the original t-stat. It is mechanical not digital. Do you mean when the problem reoccurs to test the voltage on the t-stat red and green wires for 24volts? Also meant to say that I replaced the run capacitor. From other sources, I've been told the problem could also be the fan control board or fan relay in addition to the t-stat. Any follow up responses would be appreciated.
Answer If the furnace controls is a solid state circuit board the fan replay is a little black box on the board. So I repeat the test with power off to the outside unit,\. If thje fan doesn't run, tap on the thre relay & see if that will start it. If its that relay, need to replace the board.
