Adding a 2nd A/C system

[SeaJay]

I have two ac questions, so I figured I’d post them both here instead of starting two threads.

I’ve got a 2020 JayFlight 324BDS.

1) My dometic AC is problematic. Aside from the well documented possessed thermostat problem, mine has an issue where it will cool the trailer to the set temp and shut off as it should, but then as the temperature in the cabin rises, it will not turn back on. It seems on hot days it will run and cool all day, however this usually happens at night. I go to sleep comfortable, then wake up sweaty in an 80+ degree trailer, stumble through the dark to cycle the thermostat on and off repeatedly until it finally kicks back on. Then it will cool and repeat this problem usually a couple times per night. It’s done this from day 1. I’m hoping to resolve this without the hours long commute to camping world for them to keep my trailer for weeks or even months.

2) My unit is prepped for 2nd ac, which I want to add before summer. Wondering which units I should consider. The 2nd unit will be in the front bedroom, so I’d like to get something quieter than the super loud unit that’s in the main cabin. I plan to install it myself, again, so I don’t have to leave it at a service center for an extended period of time.

The existing system is ducted. In the front bedroom there is just a sticker next to the only duct in that room. Does anyone know if the 2nd system is designed to be tied in tandem to the existing duct work? Or do you close off that duct and use the unit ductless for that room only?

[spoon059]

My first suggestion is to change your thermostat. Your thermostat is what tells the AC to turn on or off. If the AC is cooling fine, its not an AC issue. I had the original manual thermostat and we would notice 3-4 degree temp swings (set at 72, it would be between 68 and 76 degrees). Changed it to a digital thermostat and now the temp is within 1 degree (set at 72, its 71-73 degrees).

Usually your 2nd AC isn't ducted, its just a traditional dump RV AC unit. Noise depends on the size and quality of the unit. I'd think a quality 8 or 9K unit would be pretty quiet and sufficient to cool down a bedroom.

[SeaJay]

Originally Posted by spoon059

My first suggestion is to change your thermostat. Your thermostat is what tells the AC to turn on or off. If the AC is cooling fine, its not an AC issue. I had the original manual thermostat and we would notice 3-4 degree temp swings (set at 72, it would be between 68 and 76 degrees). Changed it to a digital thermostat and now the temp is within 1 degree (set at 72, its 71-73 degrees).

Usually your 2nd AC isn't ducted, its just a traditional dump RV AC unit. Noise depends on the size and quality of the unit. I'd think a quality 8 or 9K unit would be pretty quiet and sufficient to cool down a bedroom.

It’s my understanding that due to the design of the dometic system the thermostat can not be swapped with a different one. And replacing with the same style thermostat often leads to the same problem again. I’ve reached out to jayco and dometic. I know they’re going to tell me to take it in for service, I was just hoping to avoid that by learning from others with the same experience. I’d rather do the repairs myself than drive to camping world and deal with that hot mess. I’m just not familiar with these systems.

[triplebvalp]

Originally Posted by SeaJay

It’s my understanding that due to the design of the dometic system the thermostat can not be swapped with a different one.

This company makes a replacement:

https://www.microair.net/products/ea...32199143555156

[SeaJay]

Originally Posted by triplebvalp

This company makes a replacement:

https://www.microair.net/products/ea...32199143555156

Thank you.

[Lake Huron]

My Northpoint has 2 Coleman Mach 15kbtu A/C units. The one in the front bedroom is cut into the main duct run but also has side dumps on it. I keep the front dump closed and the rear mostly open otherwise itll become a sub zero meat locker in there.
My buddy has a 29.5 and his came with one A/C unit, Dometic I believe, and had the dealer install the 2nd in the front bedroom of his. It worked but not as well as he was hoping for. Come to find out they didnt install the baffle in it very well AND didnt cut it into the main duct run that was right there and simple to do. He fixed the baffle issue and opened up the duct run and re tape sealed everything. Much better now. He did say that my Coleman units are quite a bit quiter than his Dometic units. Neither of these units are going to be whisper quiet like a residential home central A/C unit but they are way more quiet than a 15kbtu window unit 5' from your head in bed. Lol!

[SeaJay]

Originally Posted by Lake Huron

My Northpoint has 2 Coleman Mach 15kbtu A/C units. The one in the front bedroom is cut into the main duct run but also has side dumps on it. I keep the front dump closed and the rear mostly open otherwise itll become a sub zero meat locker in there.
My buddy has a 29.5 and his came with one A/C unit, Dometic I believe, and had the dealer install the 2nd in the front bedroom of his. It worked but not as well as he was hoping for. Come to find out they didnt install the baffle in it very well AND didnt cut it into the main duct run that was right there and simple to do. He fixed the baffle issue and opened up the duct run and re tape sealed everything. Much better now. He did say that my Coleman units are quite a bit quiter than his Dometic units. Neither of these units are going to be whisper quiet like a residential home central A/C unit but they are way more quiet than a 15kbtu window unit 5' from your head in bed. Lol!

Mines 35’ with one unit ducted throughout. Right next to the prep for the 2nd ac in the front bedroom there is a vent from the main unit. So what you’re saying makes perfect sense. Good to know what to look out for. Though after talking to a couple local service centers, I’m probably going to end up installing mine myself. Looking at the new dometic fresh jet. Difficult to find units in stock right now.

[Lake Huron]

Yeah, they are pretty simple to do really. Especially of the wiring prep.is already there.
Make sure when you cut the roof material you cut it smaller than the actual size of the hole. This way you have "flaps" you can wrap down the sides of the hole and secure them down.
As far as difficulty finding units right now, it's difficult to find ANYTHING right now. Lol!

[Lake Huron]

Heres a couple of pics of what I'm talking about.
This first one is the unit inside the bedroom. The baffle wasnt installed properly and the duct sealing tape job needed some redoing. If you blow the pic up you can see the roof material wrapped around the sides and stapled down.

This second pic is of my main unit. You can see better how the roof material is wrapped around. The baffle there wasnt much better and there was NO tape sealing in this one.