Replacing Air Conditioners

Topic: Replacing Air Conditioners (Read 3222 times) previous topic - next topic

Re: Replacing Air Conditioners

Reply #50 – May 02, 2019, 07:51:26 pm

David getting the old unit off and the new unit on is the hardest part, old unit is probably 120 lbs. Does your coach have the controls on the ceiling unit? Four bolts and a couple of plug and play wires, and a clamp around the fabric supply drop. If you have a Coleman unit with big square ceiling assembly I would consider reusing it as you will see a shadow on the headliner material. Get a new gasket for the roof penetration.

Re: Replacing Air Conditioners

Reply #51 – May 02, 2019, 08:03:34 pm

If the Nitehawk can do it we all can do it.

Re: Replacing Air Conditioners

Reply #52 – May 02, 2019, 08:10:49 pm

The old unit is a Penguin. It has a heating element in it and a thermostat on the end of the cabinet by the door. When we were at FOT I asked about replacing the thermostat and was told that that was unobtanium. They thought they could cobble together something that might have worked, but weren't sure.

My first thought is to replace it with something similar (a/c and heating element), but I'm wondering whether a heat pump would be a better choice. Either way, it seems that the new units have all of the controls on the unit, so we'll have to figure out something to cover the hole.

Re: Replacing Air Conditioners

Reply #53 – May 02, 2019, 08:41:37 pm

David, an opinion on heat pump roof air conditioners. . .

Inexpensive devices can heat a coach, like Walmart heaters

Only roof air can cool coach, so why 'wear it out' for heating

Heat rises making heat sources from ceiling less desirable

Air conditioner compressors & coils are a completely sealed unit with no external moving parts

Heat pumps introduce a mechanical Reversing Valve in the compressor lines and a fail-point not in air conditioners

Heat pumps may not work very well at very low outside temps, when they are really needed

On top of these 'disadvantages' heat pumps cost more

Re: Replacing Air Conditioners

Reply #54 – May 02, 2019, 08:57:48 pm

One of the advantages of heat pumps. They produce over 12000 btu's of heat on 15 amps. A typical resistance box heater will only produce 5100 btu's of heat on 15 amps. This comes into play if you are long term at a park and have to pay for your electricity. Of course rv heat pumps become ineffective below 45 f or so, then box heaters, or your aqua-hot/furnace will be necessary.
Heat Pump Systems | Department of Energy

Re: Replacing Air Conditioners

Reply #55 – May 02, 2019, 09:33:35 pm

I would like to see the Decibel (DB) sound measurements of the old and new units. My "quiet" new Dometic Brisk II Air heat pumps generated just as much noise as the old Atwood Penguins. Anyone spending 2 CBs will naturally say it sounds quieter.

We all need to rethink RV air handling equipment noise and reduce noise by at least 20DB. See my noise measurement from my rig below. It says "Comfortable", but it it still sounds noisy.

Re: Replacing Air Conditioners

Reply #56 – May 02, 2019, 09:56:13 pm

DavidS
Found a board for mine finally.. Will tackle this after memorial weekend sometime.

What does " found a board " mean??

Re: Replacing Air Conditioners

Reply #57 – May 02, 2019, 10:16:53 pm

Post 53 & 54 both have valid points heat pumps are 3-4X more energy efficient in their prime zone above 45 degrees, but can short cycle the compressor at those temps. That being said any compressors start heat cycles in the motor windings. Roll the dice. So why does OPP who is a degreed HVAC engineer still have a 1993 ac condensing unit that was intentionally undersized outdoor unit. Because it provides superior comforr and reliability because its run times are quite long. There have been no economic advantages for that unit due to any technology period. Just hype produced by the marketing department. Still waiting on a unit with a decent head pressure controlled ecm motor and a composite fan with turbicles. End of rant.

Re: Replacing Air Conditioners

Reply #58 – May 02, 2019, 10:54:08 pm

Quote from: Tim – May 02, 2019, 09:33:35 pm

I would like to see the Decibel (DB) sound measurements of the old and new units. My "quiet" new Dometic Brisk II Air heat pumps generated just as much noise as the old Atwood Penguins. Anyone spending 2 CBs will naturally say it sounds quieter.

We all need to rethink RV air handling equipment noise and reduce noise by at least 20DB. See my noise measurement from my rig below. It says "Comfortable", but it it still sounds noisy.

Problem is trying to force that much air thru a tiny 14x14 opening Mr physics genenerates lots of turbulence and noise at those high velocities and fan static pressure. Once generated it's hard to attenuate. Reduce loads and airflows and the problem is reduced. Could be why the foremost/prevost uses may use 4 9k btuh units vs bigger units IDK

Re: Replacing Air Conditioners

Reply #59 – May 02, 2019, 11:15:06 pm

Quote from: Old phart phred – May 02, 2019, 10:54:08 pm

Problem is trying to force that much air thru a tiny 14x14 opening Mr physics genenerates lots of turbulence and noise at those high velocities and fan static pressure. Once generated it's hard to attenuate. Reduce loads and airflows and the problem is reduced. Could be why the foremost/prevost uses may use 4 9k btuh units vs bigger units IDK

I would think 36000 btu's in a 45 ft dark painted coach would be cutting it close. Maybe super insulated?
Most other 45 ft coaches use a total of 54000 btu's or even 60000 btu's. Is there some new technology out there?

Re: Replacing Air Conditioners

Reply #60 – May 03, 2019, 12:39:02 am

H3 is fiberglass not stainless. Less heat gain? Of course they painted it black.

Re: Replacing Air Conditioners

Reply #61 – May 03, 2019, 12:52:06 am

Quote from: Caflashbob – May 03, 2019, 12:39:02 am

H3 is fiberglass not stainless. Less heat gain? Of course they painted it black.

Will 36000 btu's handle it, even if fiberglass? My fiberglass white roof 40 footer sometime struggles with 30000 btu's.

Re: Replacing Air Conditioners

Reply #62 – May 03, 2019, 08:21:19 am

Quote from: GleamB – May 02, 2019, 09:56:13 pm

DavidS
Found a board for mine finally.. Will tackle this after memorial weekend sometime.

What does " found a board " mean??

The control board

This is not the one but you can see what I mean
Dometic 5 Button Comfort Control Circuit Board 3109229.009 | eBay

Re: Replacing Air Conditioners

Reply #63 – May 03, 2019, 11:01:26 am

I did not know what they (foremost or prevost) hence the word "may" and "IDK". air conditioning efficiency/technology is only slightly better than it was in the 90's and most of my noise is due to the small roof hole and a fan trying to overcome that small hole. Working on a water source heat pump system project that is approximately 13,200,000 btuh

Re: Replacing Air Conditioners

Reply #64 – May 03, 2019, 11:10:32 am

That would cool every Foretravel out there.

Re: Replacing Air Conditioners

Reply #65 – May 03, 2019, 11:44:20 am

Quote from: Old phart phred – May 03, 2019, 11:01:26 am

I did not know what they (foremost or prevost) hence the word "may" and "IDK". air conditioning efficiency/technology is only slightly better than it was in the 90's and most of my noise is due to the small roof hole and a fan trying to overcome that small hole. Working on a water source heat pump system project that is approximately 13,200,000 btuh

Totally agree, trying to suck air in, cool it, than discharge it back out of a 14 inch hole is hard to do without making a lot of noise. Had a coach with 3 units, compressors and condensers in the basement and evaporators with 8 in ducting discharge, in the coach. Really had to listen hard, to hear if any were running.

Re: Replacing Air Conditioners

Reply #66 – May 03, 2019, 07:10:29 pm

We have an appointment for Wednesday to get the a/c replaced with a new version of what was here. The new one doesn't use the thermostat that this one uses, so I'll have to come up with something to cover the hole in the cabinet. I may just leave the existing 'stat there, but it won't be connected to anything.

Re: Replacing Air Conditioners

Reply #67 – May 03, 2019, 07:24:06 pm

If it's a two wire or more tstat you may be able to still use it. Tell us what you got and what unit you purchased. It may not be rocket science after all.

Re: Replacing Air Conditioners

Reply #68 – May 03, 2019, 07:35:09 pm

The new units come with all of the controls on the a/c itself, so the old box isn't going to do anything. There is a ribbon cable that is maybe 8-10 wires that goes into the cabinet and from there (I assume) to the a/c.

Re: Replacing Air Conditioners

Reply #69 – May 03, 2019, 09:57:55 pm

OK, I'm sitting on the couch and have taken a decibel reading using an app on my iPad. Probably not as accurate as a professional meter but all I can say is my Atwood is much quieter than my previous penguin. Then again it was an older unit, possibly 12 years old. Anything older will not be as quiet as when it was new. It just got to when my old penguin was running I couldn't hear the tv unless I turned the volume way up. Now I don't have to.

Re: Replacing Air Conditioners

Reply #70 – May 04, 2019, 07:29:12 am

There is a business opportunity for an HVAC engineer and entrepreneur to start a company making truly quiet heat pumps. The name of the company could be "10DB", the "Sound of Rustling Leaves". This company would partner with rig manufacturers. HVAC design would be integrated into the coach from it's inception:

- Large three foot diameter, continuously variable speed condenser and air blower fans
- Continuous, multiple large air distribution plenums with six inch ducts and outlets and returns. No sharp turns.
- Super sound proof compressor box with heat pipe dissipation.
- Boondocking compatible: Highest-efficiency of any RV HVAC system. has a low-power mode for solar / lithium batteries

I know, I live in a hypothetical world, but I can dream.

Re: Replacing Air Conditioners

Reply #71 – May 04, 2019, 01:07:10 pm

Quote from: Tim – May 04, 2019, 07:29:12 am

There is a business opportunity for an HVAC engineer and entrepreneur to start a company making truly quiet heat pumps. The name of the company could be "10DB", the "Sound of Rustling Leaves". This company would partner with rig manufacturers. HVAC design would be integrated into the coach from it's inception:

- Large three foot diameter, continuously variable speed condenser and air blower fans
- Continuous, multiple large air distribution plenums with six inch ducts and outlets and returns. No sharp turns.
- Super sound proof compressor box with heat pipe dissipation.
- Boondocking compatible: Highest-efficiency of any RV HVAC system. has a low-power mode for solar / lithium batteries

I know, I live in a hypothetical world, but I can dream.

With Thor and Forest River beating everyone down on price, could a quieter, as low in height, thru the same 14' X 14" hole, a/c unit be built, by a company that could survive? Probably not the best time to enter the rv market, or is it? I do not see that potential large enough to survive, or could it be? I believe only if you got away from that opening size by the rv mfgs and ac mfgs. The biggest reason I do not see success is in my post below.

When selling Newmar product, one of the primary selling points was the quiet heatpump and ac. Customers were disbelievers that the ac units were the same as their competitors (they are), just different construction, R19 or above roof, etc., in all models. This was true thru their entire line from the gas Baystar thru their diesels with the optional 15K heat pumps, all had their special duct and ceiling construction.

Newmar and Winnebago now have extremely quiet operating ac/heat pump systems. They do it by using existing units. They also have a return plenum running the entire length of the rv on one side and on the other side a complete supply plenum running the entire length. Newmar on their more expensive luxury rvs have also added a wood grill work that almost totally deadenns the sound. That grill work is held up by a piano hinge and magnet for easy flip down cleaning.

Re: Replacing Air Conditioners

Reply #72 – May 08, 2019, 06:42:45 pm

We got the new a/c installed today. As others have reported, it is a LOT louder than the old one. Two very young guys (looked like teenagers) took out the old one and installed the new one in about an hour. A/C was just over $1000, and labor was $150 (1.5 hours), so $1200 for all. It is really nice to be able to have the a/c running, shut the door, and not have to think about whether that would turn it off.

Tomorrow I'll pull the on-off switch from the working, but sometimes wonky, thermostat and put it on the other one, which will then control the bedroom a/c.