Replacing Roof Top A/C units

[subtroll]

We're doing a major renovation of our 10 year old National MH this year, (roof work, slide seals and paint) and I'm thinking about replacing both Duo-Therm A/C units only because they are 10 years old. Both still work fine but as any electro-mechanical devices exposed to the elements, they have a limited lifetime and repairs/replacements on the road are generally more expensive.

I may even replace one 10k BTU unit with a larger (15K BTU) one.

Are there better units available?...better brands, newer technology?

I'd like to be able to use the same controller which also controls the furnaces etc.

[dougrainer]

jmaddy wrote:
I cannot locate my AC manual for my 1999 M-6350 National RV. Which brand will replace my existing units? I don't want to modify the existing hole in the roof. Does anyone know what the roof hole size is on the 6350?

Thank You in advance.

ALL National Products and ALL RV's have the same size hole for a RV roof top AC unit (14 inch square). Your AC units are made by Dometic. National always used Dometic. 1999 means you have the Dometic wall CCC 4 button tstat control system that uses a telephone type cable top communicate between the 2 roof AC units and the wall tstat. That system was obsolete in 2001. That means the easiest and simplest thing to do is purchase new Dometic AC units and I would get the Penguin Model, because THAT model has the new AC tstat control boards already installed. You only have to purchase the new 12 button Dometic wall tstat. The 1 tstat controls BOTH AC units. Just like your present Wall tstat. Doug

[jmaddy]

I cannot locate my AC manual for my 1999 M-6350 National RV. Which brand will replace my existing units? I don't want to modify the existing hole in the roof. Does anyone know what the roof hole size is on the 6350?

Thank You in advance.

[msmith1199]

The Texan wrote:

msmith1199 wrote:

The Texan wrote:
Why not replace the roof with a solid type, instead of another rubber roof that is subject to the same problems you are correcting? There are multiple companies that do this and everyone I know that has had it done is super happy with the results. It is similar to LineX or Rhino. One such company is RV Roof.com in Florida, but there are others.

Almost $5,000 for a 35 foot motorhome? Quite expensive.

Just used that website as a demo of what can be done with the roof type spray on hard liners. There are others and the prevailing prices that friends have paid, have been UNDER $3000 for a complete job.

$3k may be more reasonable. I have a one piece fiberglass roof on my motorhome and the only places I've had issues have been at the seams and around the skylight over the shower. I wonder if it would help any (and be a lot cheaper) just to put this stuff over the seams in the front and back and around the other problem areas, instead of coating the entire roof.

[Ozlander]

msmith1199 wrote:
Then what else should be replaced on the RV that is still working, just in case it fails? Fridge? Heaters? Water Heater? Engine? Tranny? Tires? Okay, I did do the tires based on age and not tread wear, but that's a big safety issue.

And the rear end.

The only thing you gain by replacing the AC's is a two year warranty.

[The_Texan]

msmith1199 wrote:

The Texan wrote:
Why not replace the roof with a solid type, instead of another rubber roof that is subject to the same problems you are correcting? There are multiple companies that do this and everyone I know that has had it done is super happy with the results. It is similar to LineX or Rhino. One such company is RV Roof.com in Florida, but there are others.

Almost $5,000 for a 35 foot motorhome? Quite expensive.

Just used that website as a demo of what can be done with the roof type spray on hard liners. There are others and the prevailing prices that friends have paid, have been UNDER $3000 for a complete job.

[msmith1199]

The Texan wrote:
Why not replace the roof with a solid type, instead of another rubber roof that is subject to the same problems you are correcting? There are multiple companies that do this and everyone I know that has had it done is super happy with the results. It is similar to LineX or Rhino. One such company is RV Roof.com in Florida, but there are others.

Almost $5,000 for a 35 foot motorhome? Quite expensive.

[The_Texan]

Why not replace the roof with a solid type, instead of another rubber roof that is subject to the same problems you are correcting? There are multiple companies that do this and everyone I know that has had it done is super happy with the results. It is similar to LineX or Rhino. One such company is RV Roof.com in Florida, but there are others.

[subtroll]

I appreciate all the sentiments and comments. Thank you.

I had two more reasons for thinking about replacing the units. The first is we plan a major upgrade to the roof soon to replace a couple of patches, remove two inoperative solar panels, remove many feet of sealing tape, replace a bathroon vent with a second Fantastic vent and add a new white EDM roof. When the new roof is in place, I'd like to stay off the roof the next few years.

In addition when we paint the entire coach this fall, the A/C covers will be painted a matching color, ie why not paint new covers rather than later end up with a mismatched set.

We're enjoying our tenth season in this National MH after starting in 2004 with zero warranty items and nearly trouble free 110k miles in all states (except Hawaii) and all Canadian provinces. By renovating the roof, replacing slide seals and a new paint scheme it will be a new coach to us and should keep us on the road a few more years.

[Jarlaxle]

Both A/C units (one Dometic, one Coleman) in my bus are 15+ years old...both work perfectly. Roof airs last a LONG time. The one in my friend's 1974 Dodge class C is original!

[B_s_Bunch]

the front ac went out on our previous coach. Had the five year extended warranty. JUST PAST THIS DEADLINE. I replaced both. Got my money back when we traded or so the paper work says??? Didnt do it for trade but we managed to trade soon after replacement. Im happy and I am sure the new owners are also. I try to take care of my equipment. Larry

[TechWriter]

msmith1199 wrote:

TechWriter wrote:

msmith1199 wrote:
Then what else should be replaced on the RV that is still working, just in case it fails? Fridge? Heaters? Water Heater? Engine? Tranny? Tires? Okay, I did do the tires based on age and not tread wear, but that's a big safety issue.

As a former National RV owner, I'd say you have a good start on a replacement list.;)

But none of the things on the list are made by National RV! Good thing since they are gone now. But on a serious note, I have had surprisingly good luck with my National RV.

I loved my former SeaBreeze. It was a well built coach.

msmith1199 wrote:

Right now I'm in the process of replacing all the plastic parts on the roof because they are all cracking or have already cracked and fallen off. After a $1500 estimate from the dealer to replace everything and reseal the roof, I decided it was something I could do myself.

Yep. I replaced my skylight and plastic fridge vent + I sealed the fiberglass roof.

Ain't it fun?

[msmith1199]

TechWriter wrote:

msmith1199 wrote:
Then what else should be replaced on the RV that is still working, just in case it fails? Fridge? Heaters? Water Heater? Engine? Tranny? Tires? Okay, I did do the tires based on age and not tread wear, but that's a big safety issue.

As a former National RV owner, I'd say you have a good start on a replacement list.;)

But none of the things on the list are made by National RV! Good thing since they are gone now. But on a serious note, I have had surprisingly good luck with my National RV. Other than some huge issues getting the original punch list items fixed, I haven't had anything break on this thing that I couldn't pretty easily fix myself, with the exception of the King Dome satellite. That thing was a piece of junk, but not made by National either. And I wanted an HD dish anyway.

Right now I'm in the process of replacing all the plastic parts on the roof because they are all cracking or have already cracked and fallen off. After a $1500 estimate from the dealer to replace everything and reseal the roof, I decided it was something I could do myself.

[TechWriter]

msmith1199 wrote:
Then what else should be replaced on the RV that is still working, just in case it fails? Fridge? Heaters? Water Heater? Engine? Tranny? Tires? Okay, I did do the tires based on age and not tread wear, but that's a big safety issue.

As a former National RV owner, I'd say you have a good start on a replacement list.;)

[msmith1199]

Then what else should be replaced on the RV that is still working, just in case it fails? Fridge? Heaters? Water Heater? Engine? Tranny? Tires? Okay, I did do the tires based on age and not tread wear, but that's a big safety issue.