Gas and Oil Home Heating Furnaces - rheem split system heat pump not pumping heat

Brief history: Mobile, Al; bought 13 year old house last August; had "A" coil replaced June 2000; fan would not shut off last week replaced contactor in air handler, fan operating ok; now when calling for heat contactor in air handler clicks, clicks, clicks until manually reset of thermostat to cause electric strip heat to come on, clicking starts again when system gets close to being satisfied and tries to shut down. Any suggestions on what to check next, have voltmeter will test.

Remove t'stat and jumper the heat circuit. If it works normally, replace stat. If not, check complete control circuit.

I would tend to think that the Contactor has a weak coil... or a loose conection ..

Thanks for replies. T'stat checked out o.k. Problem seems to be the defrost relay in the outside unit. It was clicking in sinc with inside relay and had a burnt contactor. Will replace on Monday and let you know if heat pump starts working correctly. Also checked 24v transformer and was getting a 21.4v reading is this o.k. or should it be closer to 24v? Thanks again!

Please check the voltage to your system when it is running.Some units have a "TAP" on the board for running 208 or 240 volts.Whats the difference?I like 2 see at least 24.6 volts from the transformer.Check your volts and shift the transformer "TAP" to the correct voltage.PDF