Adding a third A/C

[mtlakejim]

Thanks for everyone's feedback on this thread. Sorry if I sounded a bit harsh in some of the posts but we are extremely concerned with the desert heat that is upon us. This is a very harsh environment we are stuck in for the next 7 years!! Why booming oilfields always seem to be in the most inhospitable places is beyond me LOL......Sad thing is the folks that talk the worst about the oil patch live in places with wonderful weather and enjoy all the perks of what oil delivers to them. All the while running down an industry whose workers are dealing with the worst that mother nature can throw at ya to provide that comfortable lifestyle to the very folks who rail against them........

[KBC]

If you install a soft start (They are called hard start kit Camping World has them) on your 15K AC it will run on 15 amps

[DQDick]

Have used the third AC for the last two days with 90 degree temps and extremely high humidity, tonight we switch to the heat pump and by tomorrow night we will have to use the furnace. Interesting weather hear in Kansas.

[Teri M]

We got our a/c (for another camper, just got the Montana) at PPL in Texas. First one arrived damaged (not even badly) and they sent another one right away. The prices were the best we found.

[h2ojocky]

I have a older Montana with only a single AC unit. I am currently camping in San Antonio TX and have put that foil bubble insulation stuff in the windows. We went out sight seeing today and when we got back to the trailer this afternoon about 4pm it was 74 degrees inside! I think you may have an AC problem. I also agree that the soft start by micro air will help. Check out their reviews.

[mazboy]

just another thought....a floor a/c



https://www.google.com/search?client...oor+a%2Fc+unit

[mazboy]

here is some info too.


file:///C:/Users/Edward/Downloads/installation_manual_62856.pdf

[richfaa]

Fortunately we can pretty much control were we go in terms of heat and humidity. I can tell you that two years ago at a Rally in Shawnee,OK in July with the temp at 107 degrees and high humidity both A/C's running full blast barely kept us comfortable. The pretty dark colored Big Sky soaked up the heat .The inside walls were reading 90 degrees.

Here in Florida the temp is already touching 90 Degrees and the A/C's set at 77 degrees came on at 10:30AM. IMO Mtlakejim is doing exactly the right thing for his circumstances.

[jeffba]

Hey anything for the "kids"

[jeffba]

Jim is in the same NM campground DQDick is in. The DQ has a 3rd AC. I think Jim is on the right track.

[Hblick48]

I did the same thing as mtlakejim wants to do when I had my old Sea Breeze motorhome. Had 2 roof AC's and had 30 amp wiring. If anything else was running in the rig, breakers would trip. July in Tucson is BRUTAL! I wired 2nd ac to a separate 110 volt plug that came out of the rig near main power cable. Pugged 30 amp into its socket on pedestal. Plugged separate 110 into its socket on pedistal. So long as the pedestal had power, I had ac.

[TELECOOL]

Originally Posted by mtlakejim

I am going to add a third A/C to our HC381TH:

• Install in kitchen where current power vent is located.
• Non ducted "dump" style discharge.
• Run power separately from the 110volt on pedestal.
• Already have two Dometic Brand units so plan on getting matching third unit.

With the above, can anyone tell me:

• Can I run the larger 15amp unit on the typical 110volt outlet?
• What is the difference between "heat strips" and heat pump?
• Has anyone installed a third A/C on a 381TH or similar? I don't think it is prewired for third A/C.
• Can I buy a unit with the Thermostat built into the ceiling fixture or do I need a remote thermostat?
• Do I need a separate interior "install" kit or will the unit come complete with everything to install?

I have installed one on our Montana it was ore wired for the 3rd unit however I used a ceiling cassette that had the thermostat and fan control on the front and was vented out the cassette also.
If your worried about power you need to install an Easy Start 364 soft starters in each of your units this will cut the start up amps in half allowing you to run your unit off of a 15 amp circuit no problem
Good luck
Johnny V.
TELECOOL,Inc. licensed A/C contractor

[Marty 579]

Just as FYI, I had camping world do an estimate for a completely independent 3rd AC, by that I mean a 120V separate line to the rear of the trailer to hook to the pedestal bypassing the load sharing device. They quoted 20 hours labor plus the price of the AC. My unit is a 2018 3820FK that is prewired for the 3rd AC.

I think for my trip to Sante Fe this summer, I will try a portable AC that exhausts out the window. You can pick up a 10,000 BTU unit for less than $400. I'm not too concerned about tripping the 50amp breaker. I think that would likely only happen if all three units tried to start at the same time.

[rohrmann]

Just to be safe, I’d run a 30 line to the pedestal, and if a 30 is not available you can always choke it down to 20 in a pinch.

[whutfles]

If one AC wiill keep the dogs alive, why not call the factory and find out how you can change your current thermostat to run in 2 different modes:

Mode 1: As it runs today - both AC's trying to cool the RV at the same time (as you would use it when you are in it).

Mode 2: When you leave the RV, you poke a Mode button or flip a switch that when the RV needs air it only runs 1 AC. And if that AC fails to run or stops running when the RV still needs air then the 2nd AC kicks in. Kinda like you described the 2 AC / 1 AC operation above.

Could this be as simple as set the bedroom AC to 78 degrees and the Living Room AC to 74 degrees. If it is 82 degrees in the RV when you turn the air on they will both run until it gets to 78 degrees then the bedroom will shutoff and the Living Room will continue to run until it is 74 degrees. When it gets to 76 degrees again the Living Room will run and cool it back to 74 degrees and the Bedroom will stay off. But if the Living Room fails to run, then the Bedroom will kick on when it gets to probably 80.

Maybe it's harder for your unit to cool to these temps with 1 AC in that heat, you might have to have higher limits or a wider spread on the temps.

[DebNJim B]

Originally Posted by mtlakejim

Thanks for everyone's feedback on this thread. Sorry if I sounded a bit harsh in some of the posts but we are extremely concerned with the desert heat that is upon us. This is a very harsh environment we are stuck in for the next 7 years!! Why booming oilfields always seem to be in the most inhospitable places is beyond me LOL......Sad thing is the folks that talk the worst about the oil patch live in places with wonderful weather and enjoy all the perks of what oil delivers to them. All the while running down an industry whose workers are dealing with the worst that mother nature can throw at ya to provide that comfortable lifestyle to the very folks who rail against them........

Just want to say thanks Jim, for the work you do. We ofter hear about the big money being made in the oil fields but not so much of the long hours and harsh conditions you encounter not to mention the housing needs and shortages. I not only appreciate my affordable diesel prices but the fact the we are no longer dependent and abbliebged to mid east countries.

[mtlakejim]

Originally Posted by DebNJim B

Just want to say thanks Jim, for the work you do. We ofter hear about the big money being made in the oil fields but not so much of the long hours and harsh conditions you encounter not to mention the housing needs and shortages. I not only appreciate my affordable diesel prices but the fact the we are no longer dependent and abbliebged to mid east countries.

Thank you for your support

[mtlakejim]

I want to thank everyone for your support and recommendations.


Due to me working all the time it is sometimes difficult to do things exactly the way I want. As such we grabbed a Wal Mart vent out the window unit as a temporary fix. I WILL INSTALL THE ROOF AIR EVENTUALLY. But the Wally world unit was right there and a quick temp fix.


I also bought a Tempstick remote alarming (text and email) temperature monitor. It is connected to the campground WiFi so it will still work if we lose pedestal power. I'll put in standby power later for our private wifi and change that. But I will say so far the Tempstick works great and is big piece of mind.

[mtlakejim]

Oh by the way, I also bought a Progressive EMS surge protector. Based on the readings it appears that both factory A/C units are on same leg of 50 amp and pull about 34amps when both are running. Does that sound right to everyone?

[h2ojocky]

I would recommend switching one of the A/C ‘s to a different leg because if they both cycle on at the same time the “start” amps will more than likely overload the system. Several others have switched circuits.