Copeland Compressor Only Starts When Housing below 110 degrees F

[Fixin'Stuff]

I have a Goodman split system, Model GSC130361FA. The compressor is a Copeland CR28K7-PFV-230. Around noon on July 4th, the outside fan was running but the compressor wasn't. Installed a new capacitor the next morning and it fired right up. I thought all was well. It ran fine for several hours, until it cooled the house back down and turned off. The next time the thermostat called for a/c, once again, the compressor didn't start. The compressor doesn't sound like it's even trying to start. No hum, no nothing. Just the fan starts. So I got out my temp gun and the compressor housing was 119 degrees F from the sun shining straight down on it. Just to see, I ran some water over it, temp dropped quickly to about 90 degrees. Applied power and the compressor fired right up again.

Outside temp is currently 79, at 11 PM, and the system is cycling and cooling just fine. But this afternoon, when the sun was beating down on it, I had to cool it down again to get it to start. Is there an overtemp switch on this compressor somewhere that might be failing? I find it quite odd that it won't even try to start when the housing is over about 110 degrees F, but once started, it will run without any problem for 6+ hours non stop. The cap and contactor are both new.

Extra data point: The system also has a factory-installed 5-2-1 Hard Start kit. It appears to be working fine. If it were bad, I think the compressor would still at least try to start, but it either fires right up or just plays dead. Any ideas as to what is going on? It seems related to the temp of the compressor housing, but that could also be a red herring. I hate intermittent stuff!

 

[walta]

Just a wild guess but when it tried to run with the bad capacitor was drawing enough current to open the over load and when it would cool off it would try again and open the overload. This cycle may have weakened the overload.

Try a new overload.


Walta

 

[metlmunchr]

Agree with Walta that the thermal overload is the most likely culprit. Years ago when Carrier stopped using an anti short cycle timer in their small condensing units, we saw an immediate rise in what one of our service guys referred to as KK's (Killed Klixons). Doesn't take too many cycles for some portion of them to either get weak or just stay open.

 

[Fixin'Stuff]

I can't see any overload switch on the compressor and fear that it is inside the sealed housing. I.e., non-replaceable. I'll be pissed if I have to replace the compressor because a $3 part inside of it has failed. They don't exactly give those things away.

 

[samss]

The overload protection is internal and may be getting weak. Do you have a multimeter to check the amp draw? RLA is 13.6

 

[Dagny]

Find out what potential relay and start capacitor copeland recommends and install them.

 

[acmikee]

try cleaning you condenser coil.
check your voltage, look for burnt wires or loose connections including inside the pecker head on the compressor, inspect your contactor.

 

[Fixin'Stuff]

The overload protection is internal and may be getting weak. Do you have a multimeter to check the amp draw? RLA is 13.6

I do have a clamp-on ammeter and all seems well. It peaks at a bit over 50 amps when it starts, then drops back to around 12 amps. It ran fine all night last night. Switching off and on as the thermostat requested. It works great when the outdoor temp drops a bit. Now it's hot and sunny and the only current draw is less than 2 amps, for the fan. I'll wait a while for the indoor temp to rise, then cool the compressor and fire it up for the rest of the day. Once started it runs great and will run non-stop for hours. Totally bizarre.

 

[Fixin'Stuff]

Find out what potential relay and start capacitor copeland recommends and install them.

Those are already there. It's the 5-2-1 hard start kit. According to the wiring diagram it was actually a factory option. It is the kit that they recommend. (The service manual also specifically says that using a Super Boost style kit (the 2-wire style of hard start kit) is not recommended.)

If that were the problem, wouldn't the compressor be humming loudly as it tried in vain to start? When it doesn't start there is no noise and the only current draw is for the condenser fan motor, less than 2 amps.

 

[Fixin'Stuff]

try cleaning you condenser coil.
check your voltage, look for burnt wires or loose connections including inside the pecker head on the compressor, inspect your contactor.

Voltage is 243, no wires at the contactor even have a hint of overheating (I've seem them burn the spade connector off due to being loose when we lived in our last place. ) I also squeezed the connectors a bit to make sure they were very tight when I replaced the contactor yesterday.

Later today, when the sun isn't pounding mercilessly on the area, I'll pull the top off so that I can get to those connections on the compressor housing and check them carefully. The part that's still throwing me for a loop is that it runs perfectly once I can get it to start. I think this is a recip compressor. Do they run really cool? It never trips out once it's running. (The scroll compressor on our other unit hits 150 degrees when it's running. )

 

[larry_g]

Just a farmer fix, erect one of those pop up shade tents to keep the sun off of it. That should tell you if it really is the direct sun killing the start process.

lg
no neat sig line

 

[samss]

First and easiest thing to do is clean the condenser. It may LOOK clean. Clean it anyway. Download the emerson/copeland app. Enter your compressor model number and checkout the diagnostics. You actually need manifold gauges to verify operating pressures for diagnosis.

 

[Fixin'Stuff]

So it turns out that it was trying to start ONCE when hot, but it was tripping out so quickly that I thought the brief hum I heard was just the fan spinning up to speed. I disconnected the fan motor so I could hear the compressor better. (The units at my last house would hum for 20 minutes if they couldn't start. ) Every current measurement that I would take after that was just the fan running. Replaced the 5-2-1 hard start kit yesterday afternoon and it's been running great ever since.

Then just for fun, I got to swap out the expansion valve in the rear a/c of my Suburban. I hope there is a special place in hell for the idiot that thought it was a good idea to make all of the case screws face the floor and then bury half of them against the outside wall. It took 3 hours to get to the valve and about 10 minutes to change it. Thanks to the elegant design you even have to cut a hole in the air box to be able to get a wrench on one of the fittings.

Thanks for all of the suggestions. Reading those and sitting outside in the blazing sun gave me some good ideas and got me digging in deeper. I guess it really is hard for a recip compressor to start when the coil is 2 floors up, with 40+ feet of line in the attic getting hammered by the Texas sun.