Adding A/C to an OM366LA in an 1120

[Sitec]

Hi fella. Red Dot roof top ac units used to be very common in Australia on older trucks without AC. We've fitted a few to Telehandlers and tractors and they seem quite effective. I thought they were an Aussie thing, but found they are in the US too.

https://thermokingmichigan.com/products/reddot-air-conditioners/

 

[VerMonsterRV]

Thanks Sitec, will look into those also. So far I see the Kysor, Kalori and Red Dot. The price on the Kysor seems pretty attractive, though I have never heard of them. I have heard of Red Dot, mainly for the heat exchangers for cabin heating.

 

[VerMonsterRV]

OK, finally decided on which path to take. I am now waiting on a retailer of Dometic in Spain to send me a Paypal invoice for a Dometic RTX 2000 24v DC rooftop A/C for our cab. One thing though our truck did not come with a roof hatch so I will need to cut the opening. Would have been really nice to do before the cab repaint and interior was out. Any thoughts on how to cut the sheet metal? Would love to do it without removing the headliner but will if need to.

 

[Wyuna]

it would be best to remove the headliner, those bloody metal shards go everywhere, just make sure to make a plastic catch collector under where you are going to catch, it saves a lot of time cleaning up after, a plastic painting floor protecter works fine.

Im sure others will jump in about the cutting of sheet metal, i've just used a jig saw in the past with a metal blade, then file the edges and apply a red oxide paint

While the headliner is off, it makes sense to apply some sound deadener and self adhesive insulation foam, both items make quite a difference

Im interested is how it preforms for you, as i'm interested in using this or the RTX 1000 for my next build as a camper van cooling solution with a larger 24 volt lithium battery pack system.

i'm impressed with my 240ah 12 volt lithium battery in my current build, but i think the next build will incorporate a 300-400ah lithium 24 volt system, to try and run a decent cooling system

 

[VerMonsterRV]

it would be best to remove the headliner, those bloody metal shards go everywhere, just make sure to make a plastic catch collector under where you are going to catch, it saves a lot of time cleaning up after, a plastic painting floor protecter works fine.

Im sure others will jump in about the cutting of sheet metal, i've just used a jig saw in the past with a metal blade, then file the edges and apply a red oxide paint

While the headliner is off, it makes sense to apply some sound deadener and self adhesive insulation foam, both items make quite a difference

Im interested is how it preforms for you, as i'm interested in using this or the RTX 1000 for my next build as a camper van cooling solution with a larger 24 volt lithium battery pack system.

i'm impressed with my 240ah 12 volt lithium battery in my current build, but i think the next build will incorporate a 300-400ah lithium 24 volt system, to try and run a decent cooling system

Thanks Wyuna for the tips. As far as cab sound deadening we already did that with a 100 square foot kit of Rattle Trap Extreme. Would have been great to have cut the hole prior to our total cab refresh (cab paint, recovered headliner and rear wall, carpet on floor, painted all dash and door cards), but did not think I was going with a rooftop unit. Well at we are good at taking the headliner out .

So, once the hole is cut does anyone have any guidance if I need to somehow reinforce the roof around the cutout? This is a pic from last summer when we were doing the chassis refresh. The A/C will mount between the 2 roof ribs.

 

[Wyuna]

Its amazing how much that sounder deadener helps

looking at those roof supports and that your aren't cutting them, im not engineer, but the RTX2000 is only 32 kg, so i can't see too much issue with no supports.

If it wasn't painted already, id weld a couple of cross members in between the front and rear opening of the unit, but some steel tube tied in with Rivnuts would do the same thing with out having to weld in the truck.

But that may be overkill, as i tend to do that.

There are a few engineers on this site, hopefully one of them sees your post

 

[Sitec]

I'd tend to agree with Wyuna. If the AC unit sits nicely in between those two rails and the roof is flat enough to seal onto, then it won't need much additional support. However, depending on what the interior ceiling unit needs in the way of support and fixing, and what minimum 'roof thickness' is required, you might look to fabricating a square ring out of some thin wall RHS... With the hole cut to accept the outer edge of the RHS, this can be welded and sealed in place. This then gives you a 100% flat outside structural surface to sit the unit on and seal to, and also a nice internal 'border' to cut the headlining around. A few pieces of light aluminium could be then screwed to the RHS ring, which you could then screw the headlining to... This is how I plan to fit my Maxx Fans in the body ceiling/roof. The power lead for the AC can be fed through the RHS on the lower 'dry' side. Rough sketch attached to help explain my ramblings!

 

[VerMonsterRV]

Thanks guys, well this is now sounding like a bit more work. Serves me right for thinking it might be an easy one . I will look into the minimum roof thickness for this unit. I do know that the roof stamping for the hatch (which we do not have) is larger than the unit. Would have been perfect if it was the same size but the back side of the hole will be in the indented lines in the panel. So will have to figure out how to fill those. I have used 3M Panel Bond Adhesive before and it seems to work well, would avoid burning the new paint by welding.