Try this first before you buy 2nd AC unit or bring your unit in for AC service.

[BulletproofPJ]

Dude, your awesome... Been fighting the heat with our new Thor...hsd no idea you could do something about it....Thanks

[Jimbo56]

Originally Posted by gmtech16450yz

Well you don't even own an RV so I guess you don't have to worry about how efficient these roof AC's are.

Seriously, this all goes back to a basic question... Do you (the rest of you guys too) think manufacturers like Coleman, Thor or even Ford create products that are at 100% efficiency in 100% of the end users situations?


The factual answer to that question is no, they absolutely don't. There are few products made in this world that can't be improved upon in at least some tiny little way. It's actually what drives innovation, end users not being content with the operation of some product, and taking it upon themselves to modify it to work better. Many times those "mods" get evolved into actual production changes. And the world becomes a better place. lol.

If I trusted Ford to deliver my V10 engine with the best, most efficient engine calibrations, my RV would be down about 80 ft/lbs of torque right now. If I trusted that Thor made the most efficient RV, I'd be camping in a vastly inferior coach than I now am. And if I trusted Coleman to make the most efficient roof AC unit for RV's, I'd be a helluva lot sweatier while in my RV.

The simple fact is that these roof air conditioners are NOT running at their peak efficiency in any particular coach. The design has been basically unchanged for decades, and a few different models are supposed to "fit" all the different RV designs and configurations on the road. There absolutely IS room for improvement on operation of this particular product.

If you want to be a Negative Nelly, that's fine. Just don't keep squashing the hopes and dreams of the rest of us that like to mod things and enjoy the improvements and newfound knowledge that it brings.

I’ve got a question for you about my Coleman. 1st - it’s a 13,500 btu unit on a 28 ft box. I’ve plugged up the end runs of the ducts, put buttons in the vents to deflect more air out the ducts, got the ducts on the unit open, I’ve got the white wire hanging in the intake air. I’m in Va right now in low 90’s humid heat. Thermostat set to 62 (trying to keep it from cycling). I get 61 degrees out of the nearest duct. I can hang meat after sun goes down. But by noon, in full sun, inside is up to 85. Outside was 95. Still blowing 61 out the duct. What do you think my next move is? Oh, I’ve got reflective silver stuff in all the windows. Pillows in the vents, etc.

Your thoughts would be most appreciative.

[16ACE27]

Originally Posted by Jimbo56

I’ve got a question for you about my Coleman. 1st - it’s a 13,500 btu unit on a 28 ft box. I’ve plugged up the end runs of the ducts, put buttons in the vents to deflect more air out the ducts, got the ducts on the unit open, I’ve got the white wire hanging in the intake air. I’m in Va right now in low 90’s humid heat. Thermostat set to 62 (trying to keep it from cycling). I get 61 degrees out of the nearest duct. I can hang meat after sun goes down. But by noon, in full sun, inside is up to 85. Outside was 95. Still blowing 61 out the duct. What do you think my next move is? Oh, I’ve got reflective silver stuff in all the windows. Pillows in the vents, etc.

Your thoughts would be most appreciative.

Sounds like you've done all the right things and you A/C is working it's A## off but it's just not enough cooling capacity for a poorly insulated RV in the sun.
Parking in the shade helps - but not enough.
Upgrading your 13.5K BTU unit to a 15K BTU unit would help - minimally.
Putting an insulating curtain behind the cab to separate the cab area from the living area may help.
Putting a dump vent in the A/C cover helps - in that local area.

Your biggest relief will be to add a second AC in place of one of your vents. You will double your cooling capacity with another 13.5K BTU unit.

[Oneilkeys]

I agree with 16ACE27. The 13.5K unit in my much smaller Axis barely cooled the unit on a hot day out in the sun. You can make the situation better, but in the final analysis you don’t have enough cooling capacity and insulation in the coach to cool that much cubic footage on a hot day in the sun. After I made all the mods recommended in these threads, I found the next best thing I could do was install a curtain to cut off the front seat area from the living area and close off the bedroom (and in the Axis, the bathroom and hall area), close all the vents in those areas and direct all the cooling into the living area. At night I closed off the vents in the living area and directed as much A/C as I could into the bedroom. Reducing the area and cubic footage you are cooling really helps. Two A/C’s in a coach as big as yours is the only permanent solution.

[Edki45]

Originally Posted by Long & Winding road

I been wanting to share this for 4 weeks so I finally joined the forum today so I can share some of my success stories. This is my most satisfying (and cheapest) so far.

This might be a bit long winded for my first post but I wanted to tell the entire problem and my solution so please read along. I have read about this same exact problem 20 times + on this forum so I hope it helps others. It might save you $800 - $1000 over installing a 2nd AC unit so might be worth a try - you decide.

I will "try" and keep my other posts about my other mods more brief. (I said "try" LOL). And before you ask I will try and post some pictures later.

When I purchased my 2017 Axis brand new the 15000 BTU AC was not cold enough and was driving me crazy. The best it would do was around 85 - 87 deg inside temp after being on all day in the hot sun (95 deg + outside) while driving or parked at the “trail head” (Mtn biker here). At first I thought it was not the AC's fault and I fitted all of my windows with bubble wrap like I read on this forum (thanks to Jerry' Hurricane Mods and many others), added the extra AC cold air vent on cover, then inserted roof vent foam inserts to block all the heat that I could. That helped some (Maybe 82 deg at best) but not enough and took forever to get down to this temp once the RV heated up.

So right before I had a few things done on my punch list this spring (but after I fixed 20 + items myself first) one of the Camping World employees at service desk gave me a useful tip (imagine that- LOL) that I have NOT read on ANY forum or in any of my many searches on this subject.

He said to move the temp probe ("Thermistor probe") up a little to see if that would help but not too much so the unit don’t frost up. So after researching on that topic for a few weeks I thought I would try a few things myself before I have CW tear into it.

At first I decided insulated the AC box (on roof) really well with left over Dynomat and Frost King duct insulation (I did the entire aluminum ductwork under the plastic cover on roof). Then I used the foam rubber pipe insulation on the exposed AC copper pipes to prevent frosting up. Left it like this for a week or so - This helped some but I was really doing this to help with the 2nd mod I was planning. So I took out my automotive AC thermometer and stuck it directly in the cold air path inside RV at AC cover - it was reading about 65 deg. Small improvement (but im not sure by how much since I didn’t take a before temp – sorry).

For 2nd part of this job I removed the inside cover and used aluminum duct tape to seal up leaky ductwork and added some half inch soft foam to insulate between cover to the duct work (many small leaks - im sure this helped a lot - check yours now!).

3rd part of AC mod - I moved temp probe up about two inches or so. Make sure it contacts the coil inside fins by slide it in and then down slowly until it stops at coil. You can see this probe on the cold air return side (this is inside the RV looking up for a single white wire with metal probe stuck in the aluminum fins about one inch from the bottom - which by the way is the location the manufacture recommends - I checked. So this might void your warrantee (move it back before AC service?)).

Now tested the cold air duct again and it was down to 55 deg! I tried it out for a day and I was able to get the inside of the RV down to like 76 deg or so. Big improvement. But the next day I thought "we can do better" and "My car AC show 35 deg at the vents why only 55 deg on the rv?" so I moved the probe up another 1.5 inches (about 4 inches total – which was about the max you should go according to my research – make sure you do your own research.) and then I checked with my temp probe - It was 45 DEG NOW!! Wow. I thought that was great and I better leave it alone - don’t want to frost up the coils or screw something else up.

Final results = 75 temp in inside of RV now on 90 - 95 deg days sitting in full sun!!!! And that’s WITHOUT BUBBLE WRAP on windows!! (70 -72 in shade).

And 70 – 73 degrees in full sun with my new “ceramic window tint” (that will be a later post – highly recommend).

Success!!

I been testing it for a few weeks now before I posted this so I knew it worked well and has NOT frosted up on me. I even went on the roof to check coils/pipes after two hours full blast and not one sign of frosting up, then I check again at 4 hours - looks normal. I also removed inside cover and looked around - no frost – even on hot humid days.

We did several day trips (and one weekend) with AC unit on for 2 - 5 hours at a time and it worked perfectly. And on the 4th of July it was on for 10 hours straight and worked perfectly the entire time.

So now when turn on the AC and the RV is hot inside (90 - 100 deg!) in 45 minutes its down to 82 - 84 deg next to kitchen sink (were I keep a digtal gauge) and 72 - 74 deg in 1.5 - 2 hours! The thermostate is in the bedroom and it will show about 2 - 3 degrees warmer temp then the kitchen. Eventally it will equalize temp with all roof ducts open. It has not problem maintaining 73 - 75 deg at any given time with door opening up some and windows not covered or shade pulled down (after my window tint) or driving down the road on a sunny days. Its been realativly cool this year (90 -92) so if its 100 outside Im sure my readings will differ some.

My 4th AC mod was installing he Coleman Mach digital thermostat (I highly recommend). Really make the system work well.

I hope this helps a few of you guys either suffering with inadequate AC units or thinking of adding a 2nd AC unit.

I hope I didn’t bore you on my first post - I thought I should explain it fully so you can decide if you want to modify yours. Im not telling you how to do it – just telling you how I did mine and you take full responsibility if something goes Wrong.

Happy trails

I'm glad to hear that you got yours fixed. I just bought a 2020 Axis 25.6 and mine seldom gets below 83 degrees on a 93 degree day in the shade with bubble wrap insulation on the windshield. Also, the other thing that concerns me is that it is pulling 18 amps without anything else on. Even when the converter is turned off.
Btw, Have you found a good way to raise the front end to stock level? I am taking mine apart to fabricate some some spring spacers like I used to install on F&E 150-350 Fords that were sitting too low to align properly. There is no one within a 150 mile radius of DFW Texas that will align it so I am looking for some vintage alignment tools to do it myself. I set the toe and it is finally driveable.

[abjbrtd]

Originally Posted by 16ACE27

Sounds like you've done all the right things and you A/C is working it's A## off but it's just not enough cooling capacity for a poorly insulated RV in the sun.
Parking in the shade helps - but not enough.
Upgrading your 13.5K BTU unit to a 15K BTU unit would help - minimally.
Putting an insulating curtain behind the cab to separate the cab area from the living area may help.
Putting a dump vent in the A/C cover helps - in that local area.

Your biggest relief will be to add a second AC in place of one of your vents. You will double your cooling capacity with another 13.5K BTU unit.

The curtain helps a lot!

I took all the drawers out and put Reflectix on the outside walls, behind the couch etc.

I been wanting to try closing the bed room slide during the day, a few less cubic feet to cool.

[Ron1Z]

I tryed all of these quarks and ended up with the same result. The answer was add a second AC unit. I should have done that in the beginning. Problem solved.

[Long & Winding road]

Originally Posted by Edki45

I'm glad to hear that you got yours fixed. I just bought a 2020 Axis 25.6 and mine seldom gets below 83 degrees on a 93 degree day in the shade with bubble wrap insulation on the windshield. Also, the other thing that concerns me is that it is pulling 18 amps without anything else on. Even when the converter is turned off.
Btw, Have you found a good way to raise the front end to stock level? I am taking mine apart to fabricate some some spring spacers like I used to install on F&E 150-350 Fords that were sitting too low to align properly. There is no one within a 150 mile radius of DFW Texas that will align it so I am looking for some vintage alignment tools to do it myself. I set the toe and it is finally driveable.

Well Im still thinking of adding Sumos' to my front only. Most say that raises it about an inch. Easy install and should help with the ride and sway. But I dont mind the stock height.

[Long & Winding road]

Originally Posted by Ron1Z

I tryed all of these quarks and ended up with the same result. The answer was add a second AC unit. I should have done that in the beginning. Problem solved.

Yeah in full sun its hard to cool down the RV. Even at 75 deg in my kitchen area the cockpit is like 79 deg so its not the most confortalbe spot.

2nd AC would help but I also think something like Magna Shades in windsheild and side cockpit windows would do wonders.

But your RV is like 29 / 30 foot so thats when a 2nd AC unit makes more sense. Anyone under 27 foot IMO should be Okay with one unit.

Of coarse parking under trees (Esp the front end of the RV) helps tremendously. I had mine down to 73 deg yesterday in the shade (90 deg outside) and the AC was turning off regularly (My thermostat was set at 73 deg).

[Long & Winding road]

Originally Posted by Edki45

I'm glad to hear that you got yours fixed. I just bought a 2020 Axis 25.6 and mine seldom gets below 83 degrees on a 93 degree day in the shade with bubble wrap insulation on the windshield. Also, the other thing that concerns me is that it is pulling 18 amps without anything else on. Even when the converter is turned off.
Btw, Have you found a good way to raise the front end to stock level? I am taking mine apart to fabricate some some spring spacers like I used to install on F&E 150-350 Fords that were sitting too low to align properly. There is no one within a 150 mile radius of DFW Texas that will align it so I am looking for some vintage alignment tools to do it myself. I set the toe and it is finally driveable.

Have you insulated your bulk head (in front of the bunk / next to windshield?)? It helped mine some but in full sun the cockpit area is still too warm (Kichen area is not bad - that Axis front windsheld fights us in the summertime.. What about insulating the AC unit on the roof?

[taylorbob1]

Originally Posted by Long & Winding road

Well Im still thinking of adding Sumos' to my front only. Most say that raises it about an inch. Easy install and should help with the ride and sway. But I dont mind the stock height.

But...Sumo's really don't raise front end, AirLift or Firestone airbags in the coil springs do raise it. About an inch when inflated to 50#
At least that's my experience.

[Long & Winding road]

Originally Posted by taylorbob1

But...Sumo's really don't raise front end, AirLift or Firestone airbags in the coil springs do raise it. About an inch when inflated to 50#
At least that's my experience.

Well I think some of Forum members have said it raised it about 1 inch. But I would not purchase Sumo's for that reason.

Im happy with my ride height overall. Still on the fence on Sumo's . Might go with 500# (lightest rating). I dont want anything harsh. I will look into this fall when it cools down (To darn hot to work under the RV outside on for me).

[Tom Bowe]

Originally Posted by Long & Winding road

I thought about using the Eternalbond tape (like 3 inch wide) and stick it directly to the TPO roof starting at the AC drains to channel to each corner of the RV. Kinda like an X pattern. ....

On a prior coach, I ran a bead of Dicor self-leveling caulk on the roof to guide the a/c water runoff to the awning on one side and the slide topper on the other. No more running down the windows and sidewall. Even after the caulk self-levels, there is enough hump that the small amount of water went where I wanted. I need to do this on my current Hurricane.

[Long & Winding road]

Originally Posted by Tom Bowe

On a prior coach, I ran a bead of Dicor self-leveling caulk on the roof to guide the a/c water runoff to the awning on one side and the slide topper on the other. No more running down the windows and sidewall. Even after the caulk self-levels, there is enough hump that the small amount of water went where I wanted. I need to do this on my current Hurricane.

Yep, I been thinking of doing the same thing with either Self level or Eternbond tape. I will wait until I get around to installing my solar (one of these days) before I take of of his little nuisance.

[taylorbob1]

Originally Posted by Tom Bowe

On a prior coach, I ran a bead of Dicor self-leveling caulk on the roof to guide the a/c water runoff to the awning on one side and the slide topper on the other. No more running down the windows and sidewall. Even after the caulk self-levels, there is enough hump that the small amount of water went where I wanted. I need to do this on my current Hurricane.

I used Trim-Lock Drip Rail on the roof.
It works great for all water

There's discussion & photos on this thread:

vegas-axis-drip-rail

[Hugh.vines@att.net]

Originally Posted by Long & Winding road

Yes, I installed the digital Colman Mach thermostat (love it). I dont have any pictures but the wire colors matched exactly to the orginal analog stat. So if you have a yellow wire conect to the terminal with a "Y" on it (and so forth).



Do a search on this thermostat. Someone posted pictures and diagrams in the past. You might even find a Youtube about this stat. Good luck.

Where did you get the Colman digital thermostat

[16ACE27]

Originally Posted by Hugh.vines@att.net

Where did you get the Colman digital thermostat

Did you look on Amazon?

https://www.amazon.com/s?k=coleman+d...b_sb_ss_i_1_15

[Hugh.vines@att.net]

Originally Posted by 16ACE27

Did you look on Amazon?



https://www.amazon.com/s?k=coleman+d...b_sb_ss_i_1_15

What’s the difference in a home ac thermostat and a rv thermostat the home is much cheaper

[Oneilkeys]

Originally Posted by Hugh.vines@att.net

What’s the difference in a home ac thermostat and a rv thermostat the home is much cheaper

You are right. I used this cheap thermostat in my house and RV. It works the AC and heat and (most importantly) it allows you to set the on/off temp to within 1 degree either side. Our schedule is not such that a programmable one makes much sense. And I adhere to the “KISS” principle.

[16ACE27]

Originally Posted by Hugh.vines@att.net

What’s the difference in a home ac thermostat and a rv thermostat the home is much cheaper

Nothing really with an old analog thermostat.

For the digital thermostats:
The difference is the RV thermostat is designed to use and control 12 VDC.
A home thermostat is designed to use and control 24 VAC.

The home thermostat is capable of controlling 12 VDC but to use one in the RV you need to get one that operated off of batteries. This is a common mod that many people have done that couldn't see the need to pay the "RV" premium (including myself).