Alright, so I had Contractor #4 come over tonight and he gave me some info. He said that the outdoor condenser was not cleaned, therefore, giving off the wrong readings. He saw everything was working as it should, but the motor in the attic was making some humming sounds. After running it, turning it on and off a few times, the motor stopped working! He powered it off and it started back up with the humming noise. So for now, the A/C works as it should, but the motor is on its last leg. The tenants will be with minimal A/C, and a humming sound, for the weekend.
He wants to give it a few days to observe if anything else comes up.
The funny thing is, the tenant told me that the motor was making some funny sounds before contractor #3 even did the evac/purge. Contractor #3 said that the motor checked out ok, yet recommended the evac and purge anyway, due to the fact that the readings were fluttering etc… The outside condenser was filthy according to this contractor. Could this have been an improper diagnosis from contractor#3?
A dirty condenser coil, and an indoor blower motor that may be changing its speed will give you all sorts of strange readings.
Sometimes even good techs can chase after the wrong rabbit. That is also why it's tough to armchair diagnose systems on an internet forum. Had one of us been on site, we may or may not have caught the blower motor acting up. What would have been ideal for #3 would have been to go over that evap blower motor more closely...there are tell-tale signs one might be ready to fail even if at the moment it appears to run normally. Being that you told him about it...a vital troubleshooting lesson is to listen to the customer! Even if you the customer may know little about HVAC, you know something is wrong. When I have remembered to listen, very often even the customer's rough description spurred my brain toward the correct path to solve the problem.
Originally Posted by moparman915
So back to the underlying issue of the fluctuating guages when contractor #3 hooked them up. What would cause this? He said this was usually a condition of contaminates/ noncondensables in the line and/or air.
Contractor #4 replaced the fan motor and the tenant said that the A/C is working better than before. Much more output.
I wonder if he actually fixed anything with the first "repair". If not, I may request a refund on at least the labor.
No way to know from our side of the internet.