Hi, hope you can help with this I have a goodman heat pump (package unit, air source) and here's the problem. When the tstat is set to on evap. Motor( blower) waits approx. 10 sec. then engages turn it back to auto waits approx 90 sec shuts off. Now with the tstat in cool posistion fan set to auto ac comes on compressor runs, condensing fan runs, blower doesn't run. If I turn the unit off at th tstat wait for a couple of minutes and start it back up blower comes on runs fine completes cycle house is cool everyone happy. House warms up again ac kicks on maybe blower does maybe it doesn't. Since it doesn't happen all the time its difficult for me to diagnos. Has anyone ever heard of this before. I was thinking it might be a bad relay but unsure since fan works in the on position. I hope my explanation was good enough as I talk much better than I compose letters. Any help would be appreciated . Thanks in advance

Sounds like you have a bad thermostat.

Thanks for the response I had actually thought about that but discarded the idea after testing the red,green,and yellow wires while in cooling mode fan in auto. I found 25v on all of them even when the blower is not running. Would this still be possible even if th tstat is bad.

It sounds like a loose electrical connection or fan relay, go to the air handler and open up the panel turn off power and check wire connections. What happens when you try to run the fan on continuously? Mike

If you have 24 volts on the blower circuit and its not running its not the thermostat at fault. The newer units will use three speeds on the blower. Low speed fan only, med-low heat, high speed cooling. You may have a blower control board going bad or just a bad connection with the high speed wire on the board.

Thanks for all the responses, I checked all the connections and everything looks okay. I looked at the wiring diagram on the inside of the unit and it appears my fan only has to speeds high speed is used in both heating and cooling. I have been looking at this thing off and on for a couple of days and its driving me crazy. It could be a fan relay but I'm not sure if I'm testing it right I do have line voltage present on what appears to be both sides of the relay it also has control voltage on the other two leads. This is why its driving me crazy I can't find a clear logical reason why its not working all the time like it should. To answer acetcthe fan will run when switched to the on position at the Tstat.

Look into circute board prob.. if not consistent

I looked for a circuit board today the only one I find is a defrost control relay could this be affecting the operation of the blower. The blower seems to work fine in the heat mode but I live in the southeast so I'm not anxious to turn ac off and heat on just yet.

Hi again, Just an update got fed up with it today decided to toss parts at it started with the blower relay if that doesn't work then Ill move on.
Thanks again for all the ideas,

AC

ac101 I am having the same thing happen did you find the problem

Jlburr it would be best if you posted your own question rather than tagging on to an old one more people will see it and be more likely to respond if it's a brand new post. That being said yes I did find the problem it was a relay that was working intermittently. Do you have the same type unit I do (package unit)or is yours a split unit ? If so ill see if the part name and number for the relay I used is in my files. Post back and let me know. GOOD LUCK, AC

Yes I have the same unit thanks for any help you can give me. I did post my own question just browsing and saw your post thought I would see what you came up with thanks again

Jl the model number on my unit is PHJ048-1A I doubt your lucky enough to have the same model but here is the name of the part it is called a time delay relay I had to get mine from a local hvac supplier I never came up with a concrete test for the relay I just eliminated other items based on my wiring diagram. If you are going to replace this yourself be sure the power is OFF before working on it. Maybe these other guys on the board have a method of testing your relay that will verify if that's the problem. Im going to copy this answer to your other post as well. Post back and let me know if you have the exact model that would be one in a million. GOOD LUCK, AC

It's a long shot but check the capacitor. It is usually mounted on the blower motor. Set your meter to read capacitance (UF). It should read approximately 7.5 uf on most normal residential units. I had an intermittent fan problem just like this and never checked my capacitor. When I finally did it was reading borderline. Replaced it and never had any more problems.

Forgot one thing. Capacitors should be checked with the power off. You have to pull one lead off also to get an accurate reading. And they can still zap you so take a set of pliers and short the terminals together to discharge it just in case.

Good advise leddfoot on the capacitor I never replaced mine because it tested good but that's another possible cause.

If you have sequencers be suspect of them. They delay on and delay off after the call from the tstat. Hard to test though.