AC not cooling

Bgotro47 · 08-06-2018, 10:08 AM

2017 Hyperlite 29HFS. The AC worked great for awhile but lately it does not cool well. I had the thermostat set at 70 and it was 81 inside. Previously I thought I had a generator problem because it would shut of at various times. Took it to Cummings service and they ran it for 14 hrs with no problem. They changed the fuel pump and filter because they have seen the fuel pump quit when it gets hot. When I took it home I ran it for 19 hours with no problem. The past weekend I started the gen around 4pm Thursday and it shut off around 12:30 pm Friday. Restarted it and it ran until it ran out of fuel. I notice that it gets slugged down at times and think it is when the AC compressor comes on. One time I felt a vibration while sitting on the sofa. Since the AC is not cooling as it should I wonder if that is causing the generator to shut down. Can the AC be repaired or does it have to be replaced. I was told there should be at least a 20 degree difference in the return air and the output air. I used a ir thermometer to check it and at best had around 10 to 12 degree difference. Any ideas or suggestions.

SeaDog · 08-07-2018, 06:52 AM

I don't understand the term "slugged down" I'm assuming you mean overloaded and shuts down. 20* DT on an AC Is with clean filters return and supply air temps measured at the unit. Without know what else is running the combination of things may overload the generator when the AC compressor cycles. Unlike home AC units repair is not feasible and replacing is the norm. Take amp and voltage checks on the AC during start up and running that will give some indication of the health of the AC unit. Does it trip your breaker on shore power.

Bgotro47 · 08-07-2018, 10:00 AM

Quote:

Originally Posted by SeaDog

I don't understand the term "slugged down" I'm assuming you mean overloaded and shuts down. 20* DT on an AC Is with clean filters return and supply air temps measured at the unit. Without know what else is running the combination of things may overload the generator when the AC compressor cycles. Unlike home AC units repair is not feasible and replacing is the norm. Take amp and voltage checks on the AC during start up and running that will give some indication of the health of the AC unit. Does it trip your breaker on shore power.

The generator slows down at times when the AC compressor kicks on. What is running is the AC, LED TV, satellite receiver, and 2 small fans.The RV is just over a year old. When the outside temp is around 98 I can only cool the inside to around 81. It use to work much better than that. Checked the filter and it is clean. What should the temp difference be between the return and output air. Right now I am running it on shore power and still does not get that cool. I am going to take some temp readings in the entire trailer.

Ida Ratherbe Camping · 08-07-2018, 10:07 AM

Check your baffle between inlet and outlet of Ac. It's a foam divider behind dump vent and filter. See if it has moved or not sealed properly. Use foil tape to secure and seal

formerFR · 08-07-2018, 10:12 AM

I think you have two different 'issues', as the air conditioner basically works the 'same' regardless of generator power or shore power.

as for the generator, it's not uncommon for it to shut down if it overheats...ours has done this too, though if you restart it, it may run perfectly fine from then on. It's a mystery, and probably nothing to do with filters.

now, the air conditioner is a different story...as you stated that it 'used' to cool fine, but now seems to not. If you have time and can find a dealer, stop by and let them check out the cooling. If they deem that it's no longer cooling properly, it certainly could be a warranty repair/replacement solution...if you're still under warranty.

Bgotro47 · 08-07-2018, 10:20 AM

Quote:

Originally Posted by Ida Ratherbe Camping

Check your baffle between inlet and outlet of Ac. It's a foam divider behind dump vent and filter. See if it has moved or not sealed properly. Use foil tape to secure and seal

I already did that. There were a few opening since the foam did not stick very well.

SeaDog · 08-07-2018, 03:04 PM

Outside air temp comes into play when the AC is not sized correctly for the rig. I would think a 29' rig would have at least one 15K AC you did not indicate the size of your AC. The rule of thumb for most AC applications is the unit should be able to maintain 80* indoor temp when started prior to the indoor temp reaching 80* on a 100* day. If the AC can't do that then the rig is generating more heat then the AC can remove and may be undersized. Like has been said I would make sure the return and supply are sealed properly and check my duct work.

Bgotro47 · 08-07-2018, 03:17 PM

Quote:

Originally Posted by SeaDog

Outside air temp comes into play when the AC is not sized correctly for the rig. I would think a 29' rig would have at least one 15K AC you did not indicate the size of your AC. The rule of thumb for most AC applications is the unit should be able to maintain 80* indoor temp when started prior to the indoor temp reaching 80* on a 100* day. If the AC can't do that then the rig is generating more heat then the AC can remove and may be undersized. Like has been said I would make sure the return and supply are sealed properly and check my duct work.

It has a 15k AC unit. If I understand what you are saying then when the outside temp is 100 the inside should be 80 and will not go below that unless the outside temp is lower.

SeaDog · 08-07-2018, 04:53 PM

Actually what I was saying if its maintaining 80* or less on a 100* day it is working as it should. The unit may be able to maintain a cooler temp I was giving you a rule of thumb and not exact figure. If you have doubts have it checked by the dealer. Remember start your AC before the inside temp reaches 80* I start mine around 75*

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