Installing 3rd air unit

[Full timer now]

We have a 2018 Jayco Northpoint 381flws.
Our current 2 air conditioning unit will not cool off our camper on hot days. Some days the temp inside is the same or higher than outdoor temp. We want to add a third unit. Our rv is prepped for a third unit. Has anyone added a third air unit? If so what size do you recommend?

[Big1]

Welcome to the forum, I will go with the 15,000btu if you can I haven't done it but maybe someone who had will chime in.

[peoples1234]

Honestly, instead of adding another unit, I think that you need to fix the two you have.

[Full timer now]

Both units have been serviced by a licensed rv repair technician. We were told both units are operating properly.

[Full timer now]

Thank you for the advice.

[Mopar_Earl]

Originally Posted by peoples1234

Honestly, instead of adding another unit, I think that you need to fix the two you have.

2 AC units on a trailer that size is marginal. I have a 293RKDS two slides (35' overall) with twin 15k units and they barely cut it with dual pane windows.


Earl

[peoples1234]

I understand that an additional unit may be needed, but the “ Some days the temp inside is the same or higher than outdoor temp“ wording had me concerned. I don’t see how A/Cs that are operating even remotely normally would fall within that statement. I have a NP 377 with two acs, and while some days it struggles, but even in FL heat it never has any problem cooling down to 75-76 degrees inside.

[Mopar_Earl]

75-76! That wouldn't fly for us, we prefer 70. I couldn't sleep at those temps.


Earl

[Cavie]

Originally Posted by Mopar_Earl

75-76! That wouldn't fly for us, we prefer 70. I couldn't sleep at those temps.


Earl

the 3rd A/C is not gonna help get that low. RV's are not insulated for that kind of temp. Walls and roof too thin. You need to change your expectations. Add some fans. Good luck.

[Mopar_Earl]

Originally Posted by Cavie

the 3rd A/C is not gonna help get that low. RV's are not insulated for that kind of temp. Walls and roof too thin. You need to change your expectations. Add some fans. Good luck.

My expectations are mine and I won't change them for you nor anyone else! My two units will struggle, we do get to 70F and hold. No fans used or needed. No luck needed either. If I needed a 3rd unit, I'd install one. OP will definitely gain ground with a 3rd unit on a trailer that size. Look at those large bus motorhomes with 4 to 6 units on the roof or one or two large basement air units.


Earl

[jasum]

Magnolia Tom has a North Point and I believe he installed a third AC.

[SkyBound]

There are also some modifications that can be done to the ducts/vents which improve cooling ability. It's outlined in the 377 mods thread - just search for it. You can also add some reflective insulation inside the existing air conditioning units to improve their efficiency. Maybe start there and possibly save yourself some money.

[Zs387RDFS]

I concur with SkyBound - there are certainly things you can do to improve the factory setup including modifying (sealing) the vents, and insulating the 'doghouses' on the roof units.

I did this with the two units on my roof recently.

Some of my vents were pushing cold air right into the attic
Removing the black rings made a huge difference in increasing air flow. These rings occupy a lot of the space in the ducts which restrict the flow a lot.


I'm pretty confident I can now easily keep my rig cool (75ish) on a hot humid Michigan day in the sun with the two 15K units I now have. Much colder at night if needed for sure.



One thing I did notice with my 2nd A/C (bedroom), was that if I closed the cold air vents on the head unit, it pushed into the ductwork and added to the main A/C units output. Tons of air flow through the whole coach this way.

If you still want to install another A/C unit, I believe the power pig tail might be right there by the vent in the attic. Easy to check by removing the vent trim. Plumbing it into the existing ductwork would be a challenge, so running it in isolation might be the only option.

[lhpelton]

What did you use to insulate the "dog houses"?

[Jagiven]

Originally Posted by Zs387RDFS

I concur with SkyBound - there are certainly things you can do to improve the factory setup including modifying (sealing) the vents, and insulating the 'doghouses' on the roof units.

I did this with the two units on my roof recently.

Some of my vents were pushing cold air right into the attic
Removing the black rings made a huge difference in increasing air flow. These rings occupy a lot of the space in the ducts which restrict the flow a lot.


I'm pretty confident I can now easily keep my rig cool (75ish) on a hot humid Michigan day in the sun with the two 15K units I now have. Much colder at night if needed for sure.



One thing I did notice with my 2nd A/C (bedroom), was that if I closed the cold air vents on the head unit, it pushed into the ductwork and added to the main A/C units output. Tons of air flow through the whole coach this way.

If you still want to install another A/C unit, I believe the power pig tail might be right there by the vent in the attic. Easy to check by removing the vent trim. Plumbing it into the existing ductwork would be a challenge, so running it in isolation might be the only option.

What did you use to insulate the doghouse? It looks like metal duct tape. I'm guessing Reflex, and metal duct tape at the joints. Did it quiet down the unit at all?

[JimD]

Originally Posted by Mopar_Earl

My expectations are mine and I won't change them for you nor anyone else! My two units will struggle, we do get to 70F and hold. No fans used or needed. No luck needed either. If I needed a 3rd unit, I'd install one. OP will definitely gain ground with a 3rd unit on a trailer that size. Look at those large bus motorhomes with 4 to 6 units on the roof or one or two large basement air units.


Earl

Kind of a nasty reply to a member who was just offering his point of view. You will get a number of ideas, some good and some not so.

[rkymntsno]

Originally Posted by Full timer now

We have a 2018 Jayco Northpoint 381flws.
Our current 2 air conditioning unit will not cool off our camper on hot days. Some days the temp inside is the same or higher than outdoor temp. We want to add a third unit. Our rv is prepped for a third unit. Has anyone added a third air unit? If so what size do you recommend?

We have the same problem with our 42' Eagle 355mbqs. I've had the dealer check our two a/cs several times last summer after taking delivery. They said they're running fine. The whisper quiet a/c is the culprit I think. It does not cool as well as the 13,500 btu in the bedroom. So we have a pedestal fan at the foot of the bed and blow it down the hallway. That helps. All ducts have been inspected and they tweaked a few of the openings. Don't think I'll go with a whisper quiet ac again.

[Big1]

Originally Posted by Mopar_Earl

2 AC units on a trailer that size is marginal. I have a 293RKDS two slides (35' overall) with twin 15k units and they barely cut it with dual pane windows.


Earl

Yes, I agree, I have heard that they only cool down to about 20% inside like if it 90 degree outside it will only cool down to 70 degrees.

What we do is have a little fan inside the fiver that rotate to push the air out a little that's help.

And what I did but I haven't try it yet since I did it is went through all of my air vent and clean it up a little.

What I did it I put aluminum tape on all of the vents in the living area and the bathroom and the bedroom area.

The bedroom area the a/c unit was not properly was not install correctly so I had to take the bottom a/c unit off and reposition the buffer and tape that up.

I figure that from the factory some of the air was escaping in the ceiling and not down in the living area/ When I took all of the vents cover off they had stuff up in the ceiling, foam stuff that were just laying up there so I had to take that out.

Tape the buffer in the bedroom to the correct position so all the air can go into the room. Like I said that I haven't try it since I did it this way but I figure that I got another 20% more air flow in the room and not in between the roof and the ducting system.

[rkymntsno]

Originally Posted by Big1

Yes, I agree, I have heard that they only cool down to about 20% inside like if it 90 degree outside it will only cool down to 70 degrees.

That's what my service dept told me was Jayco's standard. 20 degrees less than the ambient temp outside. If it was doing that, Jayco wouldn't honor the warranty service.

[Mopar_Earl]

Originally Posted by JimD

Kind of a nasty reply to a member who was just offering his point of view. You will get a number of ideas, some good and some not so.

Big difference between point of view and demanding that I need to change my expectations.
My expectations are mine, not theirs. I was extremely nice about it. Trust me, I held back to the point it hurt. Lol

My units are holding their own, barely. So while they barely meet my expectations, they do. Not sure why he said I need to change my expectations. That doesn't fly for me. Maybe he meant it for the OP? No idea, I replied and moved on.


Earl