Second a/c on a Montana HC 343RLL

Dave W · 02-23-2016, 06:13 AM

Thread is here as it really isn't technical.

The OEM as installed 15K Btu Advent a/c unit is a weakling at best in a pretty big 5er and as such, want to add a second but 13.5 a/c to the prewired vent in the bedroom. There are several that fit the need but there is that question of overall height of the trailer. Currently the advertised height of this 5er is 12'9" assuming it's riding level (I can't do a physical check right now) and which looks to be right at the bedroom vent where it would be installed. 'Standard a/c units are about 13 and a bit more inches which would put me really close to 14 feet. Phew!!. There are some low profile units available from both Dometic (Penguin) and Coleman (Mach 8) at about 9 inches. I have no experience with either in a low profile configuration.

I've been told that Dometics are very loud and the quality is so-so.....but only campground hearsay. Then I also want to add a heat strip if the a/c is non ducted and something I'll check as the existing duct work is nearby.

Finally, my questions. Anyone have experience with either the Dometic or Coleman low profile units? Comments on that height?

Thanks

Travelin · 02-23-2016, 07:50 AM

We have a 2012 Montana 3150rl. Last year, had the Penguin 13.5 installed in the bedroom vent. We choose the Penguin due to our concerns of overall height issues. We did not tie into the existing duct work as our model's bedroom ducting was too far from the new A/C. Nor did we tie into the existing thermostat. The Penguin does seem to have a fair amount of air flow noise. Possibly would consider the heat strip addition.

Hope this helps with your decision

2012 Ford 6.7 F250 with airbags.

Dave W · 02-23-2016, 08:08 AM

Quote:

Originally Posted by Travelin

Hope this helps with your decision

2012 Ford 6.7 F250 with airbags.

Thanks - just helped clear the muddied waters a bit

.

I did some more 'net reading and it looks like the Coleman had a noise issue too but a different fan blade design did the 'fix' and they have become among the quietest now.

jeff57 · 02-23-2016, 08:11 AM

We had the Dometic Penguin 13.5K BTU A/C unit on our 2007 Hi-Lo. The original lasted 6 years, then fried.The original and the replacement units both did a real nice job cooling but were quite loud inside the camper. The original had the heat strip but didn't bother on the replacement.
I believe the A/C fried due to bad power from the electrical post at a busy campground over a very warm 4th of July weekend, but that's another story. After replacing the A/C, I bought a surge suppression unit and will never be without one again.

Cabindweller · 02-23-2016, 09:51 AM

We ordered our new Cougar with the second AC unit. 5er height without it is listed at 12'9". Our unit has not arrived yet but am also a bit concerned about the added height.

Does anyone know if the factory installs a low profile model when a trailer is ordered this way?

Dave W · 02-23-2016, 10:00 AM

Quote:

Originally Posted by Cabindweller

We ordered our new Cougar with the second AC unit. 5er height without it is listed at 12'9". Our unit has not arrived yet but am also a bit concerned about the added height.

Does anyone know if the factory installs a low profile model when a trailer is ordered this way?

Call your dealer!!!!!
As a guesstimate, would bet that it's identical to the Advent mounted on the rear of the roof

nellie1289 · 02-23-2016, 11:14 AM

Quote:

Originally Posted by Cabindweller

We ordered our new Cougar with the second AC unit. 5er height without it is listed at 12'9". Our unit has not arrived yet but am also a bit concerned about the added height.

Does anyone know if the factory installs a low profile model when a trailer is ordered this way?

I would be really curious what this looks like when you get yours cabindweller. these things are really tall as is. I had my head on a swivel for low clearances already, you are really going to have to watch it. I will say the rear unit in the 336bhs is pretty powerful, the bedroom does get a little warm up front but there are darn near icycles hanging off the shades in the main living area. lol

**chuckster57** · 02-23-2016, 01:23 PM

I would like to think that Keystone is as smart as the other makers and installs low profile units on the front of fivers. Seems to be an industry standard.

Dave W · 02-24-2016, 04:21 AM

I ordered the low profile Dometic Penguin ll last night. Over 200 dollars difference for virtually the same output unit plus way fewer sellers pushed me that direction. It's the 640315CXX1C0 Penguin II, manual controls, non-ducted but with a heat element to be added. The significant difference is about an inch and a half taller for this one vs the Coleman and puts it at approximately the same height as the Aero-Flow vent over which I have never hit with a low tree branch or, *gasp* bridge.

It will be interesting to see what kind the new Cougar arrives with. I honestly don't believe any trailer manufacturers give much thought to where and how a lot of 'things' are arranged. If so, a unit with a single a/c would have it mounted midships instead almost the furthermost rear point with significant heat losses in the moving air column to the more common front bedroom. It seems that they can do it with many TTs but not a pretty large 5th wheel.

gearhead · 02-24-2016, 05:01 AM

I've got 2 of the Dometics. Mine is advertised as 12' 9" as well. You'll be OK with the height. Mine measured 13'3" to the front A/C with the previous Ford. I haven't checked it hooked to the Ram yet. I just put 13' 6" in my brain. Only had to turnaround once, so far.....downtown Clarksdale Mississippi railroad underpass signed at 13'.

PND · 02-24-2016, 06:08 AM

I installed the Mach 8 Coleman on our 358RLT. Height is lower than the rear unit. Any unit will have some level of noise since the blower and compressor is right over your head in the unit. Ours cut the inside temp down from 92 to around 75 when it was 111 outside. We had no shade so units ran into the night, but much better sleeping, just turned the front unit off at bedtime. Just remember that if you only have a 30 amp pedestal to plug into, you can only run one unit at a time.

PND
2012 Silverado 2500 HD
2012 358RLT Mountaineer

WaltBennett · 02-26-2016, 03:33 PM

Quote:

Originally Posted by Dave W

The OEM as installed 15K Btu Advent a/c unit is a weakling at best in a pretty big 5er and as such, want to add a second but 13.5 a/c to the prewired vent in the bedroom.

I'm wondering about your 'weakling' comment. I've seen several posts on the Montana Owner's Club forum about collapsed or mis-connected duct work. There's also the issue of the round vents protruding up into the ducts so far that they block air flow quite a bit. That is easy to fix, the ducting issue may not be.

There's also many posts about adding a second AC and what brand folks thought were best. We've still got our single one had have found it works well enough for our camping lifestyle along with heat reducing LED lighting and window insulation. Just doing that gives us a solid 18 degree drop from outside temperatures. If you don't do something similar, even adding a second AC won't get you more than 20 - 22 degrees of temp. difference.

**sourdough** · 02-26-2016, 03:45 PM

Missed this thread and sounds like the OP has ordered the Dometic Penguin II.

That is the unit I had installed for a 2nd unit on our trailer and we've been happy with it. It is installed just as you did but without the heat strip. I think all non ducted ACs in an RV are pretty loud when you are near them (all I've heard anyway) and the Penguin is no exception. It will cool the bedroom down very nicely tho and that's what we look for on those hot, hot/muggy days/nights. Good luck with your purchase.

Dave W · 02-26-2016, 06:31 PM

Walt, appreciate your comments about the ducting and will take a look as soon as I can get a chance with the weather - and more then 2 warm(er) days in a row and no rain. Luckily we have LED lighting as built but I haven't done much of anything with the windows but do have a roll of Reflectix bubble wrap for that purpose. Unfortunately, Keystone in their 'superior' wisdom, painted the slide ends black so I'm cursed with having to paint all 8 of those 4 slide ends them. Like the insulation, have the paint, just need some decent weather.

Sourdough - thanks for the good words on the Dometic a/c. As far as quiet - never happen in an RV

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