Carrier heat pump not cooling.

I have similar issue but not exactly same. Will start new thread if advised to do so. Mine hasn't worked all summer. we really didn't try it till about 2 weeks ago. Mine Carrier heat pump with evaporator/blower in attic. it blows air but not cool and doesn't lower temp. Outside fan spins freely and starts. When I turned on AC to see if cooper tube cool, the compressor fan only spun for about a minute or two and then stopped. The blower in attic kept blowing warm air. Didn't leave it run since the fan had stopped. Was hoping this was compressor capacitor? This unit has a dual fan/HERM capacitor that is NOT bulging.

 

Caps can go bad without bulging.

 

yes, I do understand that, but if it was bulging it would have been nice and easier to diagnose! So does this sound like a bad capacitor? Any way for homeowner to diagnose with multimeter? On previous unit I had the fan capacitor go on a dual unit, couldn't find new one, and just used the old one for HERM and bought single capacitor for the fan and just ran jumper from COM on each. Thinking of doing same.

 

Most meters do not measure MFD. You couldn't find a dual cap? Yes I would change the cap first.

 

Started a new thread for you. You can certainly use two caps instead of a dual one.

 

well I guess I didn't have my current multimeter back then cause the one I have now does measure capacitance. I disconnected all the wires then used screwdriver to discharge. Tested HERM/Com and got 45.45 microfarads and FAN/Com was 5.1 microfarads. loosened the cap so I could twist it to see label and it is labeled 5/45. So I guess that is not the problem. Low R-410A or dare I say it, a bad compressor? Can I check pressure with car gauges?

 

No... the car gauges are for a different refrigerant..... you cannot interchange them.

You aren't even at the point where pressures need to be considered.
#1 - is the contactor closed ?
If yes then you don't have a refrigerant issue.

You said the condensor fan worked intermittently..... was the compressor running ?????
If it isn't the cap then it appears you need a new condensor motor.

Did you read any of the previous threads..... this is the #1 problem with A/C's.

 

From what I read, It seemed that Cap going bad was number one problem so that is where I started and did not know at time that my meter could test it. Anyway, I connected cap back up and turned on AC last evening. It ran fine and cooled for about an hour then stopped cooling. I noticed fan was not turning. Shut it off. Today, I turned it on and fan and compressor came on, as the relay kicked closed, then the compressor kicked off, but fan still running. As it did, I immediately checked voltage on switched side of relay no voltage, fan still running and relay definitely popped out. picture of relay, with right side unswitched and left side switched. Status light -yellow- flashing 1 long, pause, 3 short, pause. If push in relay, the compressor kicks on. see photo. Is this code 31-high pressure switch?

 

It's a little hard to follow what you're doing.

The contactor closes - the compressor runs - the condensor fans runs.

So at this point the contactor is still closed. Then you said the fan was running and the compressor shut off and there is no power at the switched side of contactor.

If the condensor fan is running.... then the contactor needs to be closed.

If you have a high pressure issue.... that could point to a problem with the inside blower also.

Your unit may have two contactors or a contactor with a relay for the fan. I need a model number... I can't see enough detail from your posted diagram.

 

"If the condensor fan is running.... then the contactor needs to be closed"---nope! see photo above. The contactor is only switched on one leg of the 240. The hot wires come in from bottom (two black and a green with 240V between the black wires). The right side is not switched and goes right up to the top right side. The left side has the switch. So when the switch is out, the right leg still has voltage to ground of 120, but the left has 0V to ground. So the voltage between legs is 0V. Yet the fan is still running. when the switch is pushed in, there is 240V between the legs, and the compressor kicks on. The outdoor unit is 25HPA536A300, the indoor unit is FV4B

 

The fan is a 240vac fan. It needs 240vac to run. If the contactor is open..... then one leg of the 240vac is open and the fan shouldn't be running.

From manual...
NOTE: The outdoor fan motor will continue to operate for one minute after compressor shuts off, when the outdoor ambient is greater than or equal to 100_F/37.78_C.

Ok... that tells me that the contactor does not control the condensor fan.

Are you still getting the 31 fault ? That does indicate a high head pressure issue.
hvacpartners/docs/1009/public/0a/25hpa-3si.pdf

 

yes, lights still blinking the same. Don't see 13 as code so guess it is 31. FYI, the fan runs for longer than one minute after the compressor is kicking off so this isn't normal fan operation. And it isn't over 100 degrees now either. It seems to run continuously. Strange that yesterday it kicked right off. See you are the pool guy too! Maybe just get you here in MD, LOL.

I see it says if pressure switch opened the fan will run for 15 minutes. I didn't let it go longer to see if it does shut off 15 minutes

 

Is there anything else that I can do? or do I need to have pressures checked and if pressure OK then bad switch, if pressure high, then something else such as TXV?

 

Since you are still getting the high pressure trouble code.... I'd get a tech to check the refrigerant pressures.

 

so guy came out today. pressure got to 600 and mentioned something about pressure on other side-falling?. Said bad TXV. $900 to replace if can recover system, add $640 if can't and have to replace R-410. Seems unbelievably high. Just south of Baltimore, MD. Will be calling for other estimates.

Don't know if mentioned that the other evening it ran for about hour or so, then kicked off. Sound plausible if the TXV is the problem? Tech said that if in cooler conditions in evening it might run longer until pressure gets high enough to kick off.