AC stops cooling after one hour

[CaptDan]

Our main AC (1 of 3) blows cold air for about one hour and then the temperature of the air starts to slowly creep up. If I trip the breaker, the sequence starts over. What I find odd is that the Heat pump works fine and blows hot air until not needed again. I have reviewed numerous postings online and in forums but any/all mentions of the AC "not cooling" doesn't mention/refer to the AC cooling for awhile and THEN stop cooling. If we have a freon leak, then why does the HP work just fine? Isn't it exchanging heat the same way except in reverse? It's 52 degrees outside and the HP has been pushing 85-93 degrees throughout the rig for more than 2 hours (?). The filters/screens are clean and the AC was serviced at the dealer only a couple months ago. I read somewhere where if you trip the breaker and/or shut the AC off and restart after awhile, it resets the thermostat of the AC (?). Does each AC have its own thermostat (apart from the One Control?) I'm hoping its either the thermostat, capacitor or compressor rather than a freon leak for obvious reasons. I plan to call a service tech once we return to civilization. ps the other two ACs work just fine.

[howson]

CaptDan -- an easy item to check (assuming an RV Airflow is not installed) is to look up at the evaporator coil and see if the freeze sensor is seated correctly. See https://thecampingadvisor.com/dometi...nsor-location/ Depending on your model it may look a bit different. Remove the filters and shine a flashlight into the cavity and (hopefully) you'll see the evaporator coil.

BE CAREFUL -- those coils are SHARP. Get too "handsy" up there feeling aroudn and you may cut yourself good (and bend coils...which is also not good).

Below is a pic of my Coleman I took yesterday (just finished up servicing my two units). Note the perspective of what you're seeing is from the roof with all the shrouds removed.



The next thing I'd do is monitor the compressor amperage draw. However...I think you're right that if there was something associated with refrigerant the problem should reveal itself in either a/c or heat pump mode.

[CaptDan]

Fortunately/Unfortunately I just had the dealer install RV airflow on all three units. When I cleaned the filters I could see some of the "fins". I don't remember seeing a white wire sticking into the fins. I will look again. Perhaps it fell out (?). I ran the AC this afternoon and it only lasted 5 minutes. I then flipped the circuit breaker and waited 10-15 minutes. Restarted and it's been putting out 55-58 degrees for the past 90 minutes (longer than yesterday). After the 5 minute run, I would go back to possible leak - but after simply resetting the breaker I'm now getting 85 more minutes - plus ? (it's still cooling as I type - Oh **** - I gotta go - I'm flushing the Black tank. Thanks for the info.

Howson: Thanks for the tip. I found the sensor just "hanging" so I re-inserted it. Unfortunately, it didn't solve the problem. I'm thinking when the dealer installed the RV airflow and/or did the annual Maintenace, it may have been accidently pulled out. I also (just now) realized that the fan stays on (auto setting) even after the compressor kicks off. That ain't right. So perhaps there is a problem with the compressor. in any event I'm going to try using a mobile tech (who works on ACs) take a look at it. Hopefully at worse we have to replace just the compressor. Hopefully it's just loose wires, switch or capacitor. Thanks again.

Howsen: Well well well. Once we got to our new destination (Route 66 RV/Casino, Albuquerque), I contacted an RV tech and arranged for him to come out in couple days to look at the AC. He thought it was acting strange but had some ideas. He agreed that if there was a refrigerant leak it would affect the HP as well. Well, low and behold, I tried the AC and it worked for 4 hours before shutting off at the desired temp (???). Reset it and it worked again. The next day I ran it over and over again and each time it did what it's supposed to. Set on auto, the fan turns off after the compressor shuts off. There is a "waiting" period for about 4-5 minutes before the One Control switches from "waiting" to "idle". The AC will not restart until after it says "idle". The main AC vent temps range from 52-54/55. I also ran the HP in the mornings and it is blowing an impressive 45 degrees (96) higher than the outside temp (51). Blows in high 80's - low 90's when it's 45 outside. I understand that the "AC" setting should only get a 20 degree difference but I guess the HP is more efficient (?)
Anyway, we cancelled the mobile tech. My only guess as to what happened is that after replacing the freeze sensor, it took a few cycles to re-calibrate itself with the other components and now working smoothly. Again, Thanks for the help. Dan

[howson]

Fortunately/Unfortunately I just had the dealer install RV airflow on all three units. When I cleaned the filters I could see some of the "fins". I don't remember seeing a white wire sticking into the fins. I will look again. Perhaps it fell out (?). I ran the AC this afternoon and it only lasted 5 minutes. I then flipped the circuit breaker and waited 10-15 minutes. Restarted and it's been putting out 55-58 degrees for the past 90 minutes (longer than yesterday). After the 5 minute run, I would go back to possible leak - but after simply resetting the breaker I'm now getting 85 more minutes - plus ? (it's still cooling as I type - Oh **** - I gotta go - I'm flushing the Black tank. Thanks for the info.

When you state "main a/c" is this the one above the island? When it's running, are the other two units on, too?

What I'm thinking is the three RV Airflow units are causing too much backpressure 'cause they are too efficient and overwhelming the ductwork's ability to easily move the air. (I had this issue in my 315RLTS.)

See https://gdrvowners.com/forum/operati...s-2019-315rlts and especially GDRV-Emily's note in post 11.

Howard

[CaptDan]

Doesnt matter whether running alone or in tandem. Same thing happens. Usually just run the main. Turns out that the freeze sensor was just dangling as previous poster said to check. Unfortunately, after replacing - no change. I think its the compressor now since I finally recognized that the fan stays on after the compressor kicks off and stays on until i turn it off (compressor never comes back on). That should not happen on auto. I'm going to have a tech look at in in the next week if/when I can find one that works on HVAC. Thanks

[Harry]

Our main AC (1 of 3) blows cold air for about one hour and then the temperature of the air starts to slowly creep up. If I trip the breaker, the sequence starts over. What I find odd is that the Heat pump works fine and blows hot air until not needed again. I have reviewed numerous postings online and in forums but any/all mentions of the AC "not cooling" doesn't mention/refer to the AC cooling for awhile and THEN stop cooling. If we have a freon leak, then why does the HP work just fine? Isn't it exchanging heat the same way except in reverse? It's 52 degrees outside and the HP has been pushing 85-93 degrees throughout the rig for more than 2 hours (?). The filters/screens are clean and the AC was serviced at the dealer only a couple months ago. I read somewhere where if you trip the breaker and/or shut the AC off and restart after awhile, it resets the thermostat of the AC (?). Does each AC have its own thermostat (apart from the One Control?) I'm hoping its either the thermostat, capacitor or compressor rather than a freon leak for obvious reasons. I plan to call a service tech once we return to civilization. ps the other two ACs work just fine.

Had a similar issue with the AC in my 22RBE not cooling. Checked and the unit was freezing up. Replaced the freeze sensor, didn't help, still freezes up, its back at the dealer now. ATt 91 f outside with the AC set at 75 high fan and later at 85 high fan, still froze.

[CaptDan]

Turned out that (apparently) is WAS the freeze sensor. It seems it just took a couple days/cycles after re-inserting it and it started running fine again. It's now been 2 weeks and it's still running fine (knock on wood). Good luck with yours.

[howson]

Had a similar issue with the AC in my 22RBE not cooling. Checked and the unit was freezing up. Replaced the freeze sensor, didn't help, still freezes up, its back at the dealer now. ATt 91 f outside with the AC set at 75 high fan and later at 85 high fan, still froze.

Most likely the coolant is leaking out of the unit. If you know how to check for the amperage load when the compressor is running, what you'd see is a relatively low amperage value. This is because the compressor isn't pushing against a well-pressurized system. Only recourse is a new air conditioner, unfortunately.