Poor AC performance

[Goodspike]

Originally Posted by crah

Coleman mach 10's run the fan backwards so it less efficient while moving. The condenser is in the rear of the AC and the fan socks the air into the AC unit and it goes out the side. In the mach 8 models they changed that. Some people have installed their units backwards to fix that problem. I dont have an issue while driving because the sprinter cab chassis AC works great.

At first I was thinking that didn't make any sense, but maybe the concern is bugs! Some parts of the country that could be an issue.

[crah]

Originally Posted by Goodspike

At first I was thinking that didn't make any sense, but maybe the concern is bugs! Some parts of the country that could be an issue.

No different than car radiators. They could simply put a mesh screen if it was a concern.

Different models have fans that blow up. Based on looking at the design, it seems the easiest/more cost effective way to make it.

[Goodspike]

Originally Posted by crah

No different than car radiators. They could simply put a mesh screen if it was a concern. .

I thought about that, but it would be more visible on a radiator, and safer to clean.

But hey, I'm just trying to justify how an engineer could think it made sense to go against the flow!

[Quaterman]

Your AC is doing all it could do 16 to 20 difference do you have a curtain to isolate the cab.

[Goodspike]

Originally Posted by Quaterman

do you have a curtain to isolate the cab.

Good suggestion.

[09 harley]

Originally Posted by crah

Noticed a couple of weeks ago that my AC struggles once 90 degrees hit. Seems once i hot 100 degrees, the most I can get inside the View is 85 degrees. Living in the Southwest this isn't going to work. Have had numerous previous motorhomes and never had this problem. Are there any common problems that the views could have? Seems my supply/return difference is about 18 degrees which is within spec. I've sealed my plenum, insulated the roof box, etc and it may have helped 2-3 degrees.

Not sure if you have a Coleman-Mach unit but they are all about the same. The main way to improve performance is to improve air flow. Take the outer cover off. The air outlet is comprised of curved slats that actually impede air flow. You’ll have one or two sections for the exhaust. The exhaust air is blowing into a C shaped section and this really restricts the flow. Try blowing through this section and you feel it come right back to you. The air intake isn’t really affected because it flows in rather than out. Cut out all the exhaust bars and replace with aluminum screening like a screen door has. If you check the air flow with an anemometer you will see that the airflow will be double what it was. The difference is less run time and much better cooling. Just do it!

[bkg]

Originally Posted by crah

See pictures for reference. This area has a bunch of air escaping from the ceiling ducts. Looks like I need to deal up some of the ducts.

Although you have the 2020 new design, I have the 2019 with the higher cab-over fiberglass cap, but viewing your photos of the side panel transitions removed, it looks very similar to my 2019. The A/C grill in that transition has a "duct boot" so its technically not blowing in the ceiling via the transition trim.
I removed my entire ceiling transition (the runs from drivers side wall to passenger side wall) where the coach celing changes to the cab-over ceiling. Once the roof changes from the built-up coach portion to the molded fiberglass portion, the insulation changes from block foam (main coach ceiling) to reflective bubble sheets - roughly an R value of 1.0. Not much that can be done to improve the insulation since the space is very crowded.

I would recommend using an infrared thermometer to check for hot spots through-out the coach. Front cab area (windows) is likely to be the worse. Insulate or isolate where you can.

Another note is that the Coleman Mach fan does pull air from the back side of the coil but this doesn't hardly affect the efficiency of the condensor, even when the coach is in motion. The condensor air pushed out or entering in from the side louvers is negligible. Airflow is what is important and when the coach is in motion, airflow doesn't want to curve that hard to get in the side louvers. This is confirmed by your measured temp. split.

Like you, I've had Dometic and both 13.5k and 15k roof units and the one Coleman Mach 15k unit. HVAC used to be my trade and I have found the Coleman Mach unit better constructed than the Dometic. Take the ceiling grill for comparision; the Dometic has numerous "leaks" in the grill design making the air filters pretty much useless. Dometic plenum box is also poorly designed in comparison.
Not trying to turn the topic into a brand debate but matter of sharing my knowledge and experience of these major bands.

One final tip, leave your HVAC fan set to ON, not auto and just let the compressor cycle ON/OFF. The constant air circulation is more efficient in hot weather. Yes, the fan noise is a constant but I find that I get acclimated to it in an hour or so.

I came from the days when we used to place water sprinklers on our roof to help reduce the heat load.

Bobby

[Red Sky]

Good discussion. One small add: we lived on a sailboat for 11 years before land cruising full-time the last 6 in Class C’s; in the boat in Central America I learned to turn on the AC full bore about 4pm & shut it down when we went to bed. This cools the “box”. Then overnight the cool box helps keep the occupants cool. A fan to move the air helped, too. Even if you want to run the AC all night, the cooler box means less RADIANT heat so the perceived temperature is lower.

[crah]

Thanks to all for all the comments and suggestions. Just want to point out this is not my first RV. I have 2 in my driveway right now and have been RVing in Vegas for 15 years. The 2020 View is the first one I've had major problems with the AC keeping up. I have reflectix tyoe cover for all the windows just like my other RV's. In my pictures there is raw fiberglass that has zero insulation at the transitions from the high part of the cab. The AC leaks into that area quite a bit. I'm aware of the duct that goes into the upper bunk. This is not part of that duct.

I believe the AC itself has plenty of blowing capability, but with the ceiling assembly installed, it severely restricts the airflow. And the leaks in the ductwork makes the situation much worse. I've had the AC completely apart and am familiar with how it works. There is actually lots of video and other forums that address the Coleman install issues. Some posters already mentioned the lack of air flow. I've already ordered a different type of ceiling assembly that will hopefully help. I'm not sure if its compatible with this particular unit. I also plant on spray foaming the open crevices to nowhere up in the ceiling duct.

[Phil G.]

In extreme heat, we make smaller the interior of our motorhome that we want to keep cool -> so that the A/C has less interior air volume to process.

Our Class C came from Winnebago equipped with curtains using snaps and tracks so as to be able to block off - from floor to ceiling - the rear sleeping area and the front cab and overhead bed areas. This works great to help the ducted A/C system keep the central living area comfy in any outside temperatures we have encountered so far.

I close the A/C outlet ducts in the areas that we curtain off. The intake of the A/C system is in the main area we live in during the day. I also always set the A/C to the mode where it's fan is constantly on ... so as to provide continuous air circulation ... even though the compressor is cycling on and off.

Once when were parked in the boondocks in triple-digit temperatures for a while, I idled the engine and used both the motorhome's cab A/C system - along with the generator and coach A/C system - to make and keep the main living area nice and cool. With a Class C motorhome engine that can be harmlessly idled for awhile (some should not be idled much), this serves as kindof an emergency way to get and stay cool in extremely high outside temperatures.

[fsantore]

Crah, please keep us posted on your mod’s performance once completed. We’ve been in class B’s for more than 40 years, and I’ve always found the A/C units to be worthless. Up to 90 deg we’ve not felt a need for the air, and 90 and beyond the units just roared like a 747 with insufficient cooling. Picacho Peak overnight two days ago and we just ran the FantasticFan rather than deal with the A/C at 110 degs. The noise was particularly irritating. Hitting the 70 year old mark a couple weeks ago, we ordered a 2021 View 24D which should arrive in mid August. I’m really hoping the A/C will suit us better. We travel between San Diego and an AZ/NM southern border home, so we spend a lot of time traversing or camping in the desert. The change was driven more by not wanting to assemble the bed each night after a long day of driving. Your LV experiences on this subject will be of great interest to us.

[crah]

Originally Posted by fsantore

Crah, please keep us posted on your mod’s performance once completed. We’ve been in class B’s for more than 40 years, and I’ve always found the A/C units to be worthless. Up to 90 deg we’ve not felt a need for the air, and 90 and beyond the units just roared like a 747 with insufficient cooling. Picacho Peak overnight two days ago and we just ran the FantasticFan rather than deal with the A/C at 110 degs. The noise was particularly irritating. Hitting the 70 year old mark a couple weeks ago, we ordered a 2021 View 24D which should arrive in mid August. I’m really hoping the A/C will suit us better. We travel between San Diego and an AZ/NM southern border home, so we spend a lot of time traversing or camping in the desert. The change was driven more by not wanting to assemble the bed each night after a long day of driving. Your LV experiences on this subject will be of great interest to us.

I think you will be disappointed in the AC performance. The AC is loud, and with the mods I made it's even louder. At 110 outside, I can get about 80 degrees inside now. The transition from the high bunk ceiling to lower ceiling had zero insulation. I think a previous poster mentioned that his older model had at least reflective bubble wrap. My 2020 had zero insulation or reflective wrap. It was all raw fiberglass. I ended up insulating it with double layer of denim reflective insulation. On the supply side of the ceiling chill grill I added another grill. This all helped a little bit here and there. I also added a soft start to the AC to quiet down the compressor start up loud boom (now that I can get my compressor to cycle because I can get it to my desired temp after the mods). I'll try to post some pictures. For anyone thinking you have to live with the terrible AC performance, you can make it better. It won't be a magic cure but every little bit helps.

[crah]

These are pictures of the uninsulated fiberglass at the ceiling transition. You need to remove all the plastic trim in this area. Not overly complicated, but a lot of work to do on a new RV. Winnebago should have insulated this area from the factory.

[crah]

This is after I insulated.

[creativepart]

Originally Posted by crah

These are pictures of the uninsulated fiberglass at the ceiling transition. You need to remove all the plastic trim in this area. Not overly complicated, but a lot of work to do on a new RV. Winnebago should have insulated this area from the factory.

That Styrofoam is the insulation. It may not be super effective, but it's there so it can't be claimed that the factory didn't add any insulation.

[crah]

Originally Posted by creativepart

That Styrofoam is the insulation. It may not be super effective, but it's there so it can't be claimed that the factory didn't add any insulation.

I'm talking about the verticle surface. If you look at the yellow portion of the picture, that is daylight going right through it. That is raw fiberglass.

[creativepart]

Originally Posted by crah

I'm talking about the verticle surface. If you look at the yellow portion of the picture, that is daylight going right through it. That is raw fiberglass.

Sorry, I thought I saw a single sheet of 1" foam between that section and the top of the ceiling?

Is that a front or rear cap - what area is the photo showing?

Your insulation looks much better.

I've fully documented the lack of any insulation in the front cap of my Adventurer - and many others have had the same issue with heat over 130 degrees up there. A good number of us have insulated our front caps with pink batting insulation.

[crah]

Originally Posted by creativepart

Sorry, I thought I saw a single sheet of 1" foam between that section and the top of the ceiling?

Is that a front or rear cap - what area is the photo showing?

Your insulation looks much better.

I've fully documented the lack of any insulation in the front cap of my Adventurer - and many others have had the same issue with heat over 130 degrees up there. A good number of us have insulated our front caps with pink batting insulation.

For the view, this area is the front overcab bunk transition. The overcab bunk has a higher roof than the roof line behind the cab part of the chassis.

My Holiday Rambler diesel pusher didnt have insulation at the front cab just like your adventurer. Seems like a common theme with these manufacturers. A bit disappointing, but not surprising.

[crah]

Here are pictures of 2 grills I added. The grill that is on the AC cover/chill grill made the most difference. The air plenum has a square hole right above this vent that blows forceful air directly down. The offset is the wind noise is even louder.

The other vent is installed at the ceiling transition to the bunk area. The ceiling ducting ends at this cavity area and travels through a void up to the bunk. This one is effective if you close all the vents at the ceiling chill grill and duct through the ceiling only.

[fsantore]

Great info. I’ll need to receive my coach before the photos will ‘click’ for me. Having never seen this vehicle in person, I’ll need some hands on time before all this makes sense. I’m hoping your characterization of ‘loud’ is not as bad as our Pleasure-Way Plateau TS. On the 24D, I see the A/C unit is roughly over the front lounge rather than over the Murphy bed. In our class B, its to the rear of the vehicle over the bed, with the generator directly under if no shore power. Talk about a ‘noise sandwich’! I can’t imagine the 24D being as bad. Thanks again for taking the time to write this up. I’ll be reviewing it closely in 3-4 weeks I hope. If your travels take you to San Diego let us know. Our Bellagio trips have stopped due to the virus.