AC problem from hell: Now compressor is turning off.

Craig,

I believe that's the first theory that covers everything. First, why did the rear bearing go out on the motor in less than two years when the first motor lasted 12? Could have been a manufacturing defect for sure. But it could have also been slightly uneven drag on the fan. On the original motor, it was the front bearing that went out and I believe it's almost always the front bearing from what I've heard. And not like this. There was no wobbling of the shaft on the first motor. It was the bearing freezing and I was able to get by with lubricating it until I got the new motor.

The capacitor going out so fast is also unusual. That, I've been told, is probably related to the motor and now possibly related to the motor working extra hard.

Still, it's somewhat unusual to have two problems at once. When those two were fixed, and everything seemed to be working great for over a week, what are the chances of something entirely new going wrong? And of all things, it's the compressor acting like it's going bad. That's seemingly unrelated to everything else I believe. But then I'm clearly having bad luck for some reason. I must have offended the universe or something because when my wife was bringing home a new AC for the RV, the AC suddenly went out on the truck. So there's that.

Back to your theory. It's very possible that those coils are partly clogged. I've only cleaned them two or three times in 14 years and I'm thinking the last time was at least five years ago when illness got me really behind on repairs and maintenance of the RV. And I never cleaned them as you described which makes a lot of sense.

So. I'll clean then as you described and we'll see what happens. I have access to a pressure washer, but it's one of those awkward borrows because they have to break a rule to loan it to me. Do you think one of those hose nossles that's supposed to mimic a pressure washer would do the job? Also, there are some bent fins. Not a lot but more than I would like. They came with the RV and I missed them (not on my extensive checklist). Should I get the tool and fix them?

Note on the truck: Mechanic found a fried clutch that was not capable of engaging the compressor. He said the compressor wheel was turning freely, but not coming on. He did have a reason to suspect the compressor might need to be replaced too. So I'm now referred to the AC garage of my choice. He's new to the valley and knows the options but does not know which is best. So we're doing a work around with our other vehicle until we get back to our home base in December.

The motor may be involved too. But I think I have to clean the coils to know. It's capable of running strong. It's still unclear to me why it seems to blow air into the RV at two speeds. Fast when I'm getting cold air and a bit slower when I'm not.

On the electrical, I know my meter will detect continuity. Not sure on the other. I know it does a couple of things I didn't understand. So maybe. I've gotta find the sucker. That means my wife needs to remember where she put it when I left it out "too long" or I have to think like her and guess where she put it. Lord help me! I'll find it and there's a good YouTube video on checking all the electrical using a simple check list (assuming the meter does it all).

Sounds like I'll be having fun in a few days once the foam arrives. Thanks so much for helping out.

Bill

I drove my grand Cherokee to a Frys store in Goodyear one summer afternoon and the AC was working fine. I came out a few minutes later and it was blowing warm. I looked at the cond. coil and a rock punctured it and the refrigerant was nearly gone. They can go that fast! A trip to our on-site/campus napa and a couple hours later and it was fixed.
Foaming coil cleaner, Foaminator from Johnstone Supply, works great but if you can't get anything like that, use all purpose cleaner or dish liquid/water to soak the cond. coil. I put a larger/low pressure narrow angle tip on my washer and spray the water straight thru the coil so not to bend the fins. A fine high speed spray like that is safer on the fins that a garden hose. A garden hose CAN do serious damage. Also clean the evap coil and the indoor blower wheel as good as you can. Try that and see if it works better. Craig
My rv AC is 13 years old and I do regular cleanings and it still works like new. Craig

Have you cleaned the cond. coil? I'd start there. That can cause high compressor amp draw, big time. If you don't have an amp clamp you can skip amping the compressor and use a volt meter to see if the external OL or the internal protector is opening. A dirty cond. coil is enough to cause your problem and if coupled with an underpowered/slow running fan, it will be even worse. At least the OLs still work, if it still cycles. It's hard to find replacements for burnt electric components on those things.
I used to get frequent service calls on rv ACs when I worked in the Az. desert and I could fix most of them... Until the problems were burnt electrical parts. Craig

I didn't get a chance to check it tonight, but there are frequent times when it sounds like the motor is turning slower and this coincides with less air flowing out of the vents. One time this happens is right around the time when the compressor turns off prematurely. When I test the air coming out of the vent, it's still cold, but a little warmer, and there's less air moving. Maybe that's normal. I don't know. But it's possible what's happening coincides with motor speed.

Got the window AC in when it was 104°. It might be the hottest day this year according to the extended forecast. I can't believe how big of wimps we've become. Sunday was 40th wedding anniversary and we talked a lot the heat and feeling old.

The 2020 AC saga continues. It's a 42 mile drive to town. My wife went and picked up the window unit. She was 16 miles from home and the AC stopped working on the truck. Strange. Fortunately, we do have a mechanic nearby. Hoping it's simple. There was no indication of a problem until it just happened.

PatJ wrote:
Doug do you know if these RV compressors have internal thermal overloads like small residential? Maybe your new condenser fan is not moving the air the old one did and you are going out on thermal. They auto-reset but it would take a long time to come back on once it went off (an hour?) not like a regular "cycle."

Also only mentioning this because I've seen it before by a skilled installer (not on an RV) but is the new condenser fan motor turning the right direction?

Yes they do have Overloads for the compressor. Some are internal and some are on top the Compressor under the wire cap. Doug

So here's where I'm at at and some of this info my be helpful to others.

I almost missed the biggest con of them all on the very popular portable air conditioners that people love so much. The hot air going outside is inside air. Lots of negative things about that, but for an RV it's a deal breaker because they aren't close to air tight. I'd be making cold air while sucking in hot air rapidly.

Another negative is they have to be 20" from anything around them. Try finding a place like that in an RV bedroom. We don't have it. The unit was small, 14" wide, but the footprint is potentially 54" by 34".

So... My wife is picking up a window AC that should be easy to install and get us to the cooler months in Oregon when I can leisurely get the top AC fixed. This is funny. The only one that makes any sense to buy has all the bells and whistles I would never want. You can talk to it and tell it what to do. Some people like that. Best thing though is it has an app. You can control it from anyplace. I think that feature might help resale. Being able to turn it on before you get home sounds pretty cool.

So, once I have cool air, I'll keep trying to figure out if it is the compressor for sure before buying another unit. Tonight I'll update you guys with specifics on what it's doing now that it stopped doing anything to cool the RV. Someone mention that maybe it's an issue with the new fan motor. There's reason to think there might be.

Doug do you know if these RV compressors have internal thermal overloads like small residential? Maybe your new condenser fan is not moving the air the old one did and you are going out on thermal. They auto-reset but it would take a long time to come back on once it went off (an hour?) not like a regular "cycle."

Also only mentioning this because I've seen it before by a skilled installer (not on an RV) but is the new condenser fan motor turning the right direction?

philh wrote:
is there a chance there's some cold air leaking into the return air flow and tricking the thermocouple thinking the air is now cold? I had this issue on my brand new TT.

This would not cause a compressor to kick on and off within 3 minutes. Not even 30 minutes. Doug

Phil, There may be a chance. Do you remember where the leak was? Was it associated with the lower (inside) part of the unit? Thanks.

is there a chance there's some cold air leaking into the return air flow and tricking the thermocouple thinking the air is now cold? I had this issue on my brand new TT.