Adding 3rd AC unit

[footdoc]

Has anyone done this on a 43 incorporating the existing ducts....my units have the proper temp differentials....about 20+ degrees but it's just poor design with too much coach and windshield in the south for only 30K BTU....approx costs and names of installers and is it worth it//????

[CorporateMonkey]

I can't help you with specifics for you coach, but I have been down the same path.

I was looking to add a 4th...


From my research I see little reason why you couldn't do it. The only issue would be running the proper wiring.

Now for how to go about this, you need to start reading up on the Winnebago forums (serious here). It seems the packaged basement a/c units Winnebago has used for about the past 10 years have been both unreliable (due to poor installation), and when they started making 40ft+ 4 slide coaches the system was undersized.

In my research adding roof A/C to a Winnebago is a common upgrade. The owners seems to have a installation path that is pretty well worked out.

The only difference is they are installing a non-ducted A/C where you would be installing a ducted version. From my point of view the difficulty difference is minimal.

I am going to assume the Winnebago owners know of reputable shops that can do the work for you.

Hope that helps.

[Norm4015]

When I bought my Dutch Star I had the same problem. The output from the two air conditioners was a 22 degree drop which is excellent, but the front of the motorhome never cooled properly. The kitchen, bathroon and bedroon would get cold, but not the front. I had Newmar add an additional outlet vent in the front for more air flow and it made a world of difference. Now the front stays cool.

It is an easy and inexpensive job. (Newmar did it free.) You can buy a vent for a few bucks and cut the hole yourself. Use a little caulking and screw the vent in the ceiling. You can add a couple of vents if you want.

[JohnParker]

Hey Norm4015!

Thanks for the suggestion. I was about to look at adding a third unit but will try an additional vent before I go that far.

I acquired an '07 DSDP 4023 in August. My previous unit had no trouble getting 30-35 degree drop but it had no slides. I expected that the DSDP, since there is much more volume to cool, would not do as well but I was surprised to only see a 20 degree drop. I called several service centers and found that 20-25 degrees is about as good as you can expect. So, I was about to grin and bear it or consider adding another AC unit.

Does your DS have ducted air? Did you add a return air vent as well as the cooling vent?

[pasdad1]

Quote:

Originally Posted by JohnParker Hey Norm4015! Thanks for the suggestion. I was about to look at adding a third unit but will try an additional vent before I go that far. I acquired an '07 DSDP 4023 in August. My previous unit had no trouble getting 30-35 degree drop but it had no slides. I expected that the DSDP, since there is much more volume to cool, would not do as well but I was surprised to only see a 20 degree drop. I called several service centers and found that 20-25 degrees is about as good as you can expect. So, I was about to grin and bear it or consider adding another AC unit. Does your DS have ducted air? Did you add a return air vent as well as the cooling vent?

How were you measuring that 30-35 degree drop? Temp outside vs. Inside? Normally AC temp differential is measured by comparing air intake with outlet air temps.

[allynne]

Corporate Monkey,

Why check the Winnebago site, if you have a Newmar product?

Al Sawyer
'05 MADP

[Norm4015]

Quote:

Originally Posted by JohnParker Does your DS have ducted air? Did you add a return air vent as well as the cooling vent?

My Dutch Star has Newmar's standard ducting system with a return duct and an outlet duct running the length of the motorhome. Newmar offered to install an additional outlet vent, but not an additional return vent. I thought about installing an additional return vent myself, but it was not needed.

The correct way to test the cooling of an air conditioner is turn it on and set the temperature low so it doesn't cycle off. After the air conditioner has run 15-20 minutes non-stop, take temperature measurements. Check the return air temperature in the vent nearest the air conditioner and then take the temperature in the outlet vent nearest the air conditioner. The temperature difference should be 20 degrees. If the air conditioner is cooling the air 20 or more degrees it is working properly. If it is cooling less than 20 degrees there is a problem.

[CorporateMonkey]

Quote:

Originally Posted by allynne Corporate Monkey, Why check the Winnebago site, if you have a Newmar product? Al Sawyer '05 MADP

Simple: Most RV's (excluding Bus conversions here) are constructed in a similar fashion.

Almost all RV's use the same component (like a Dometic A/C) and since adding an A/C to a Newmar is a fairly rare occurrence, I suggested looking on the Winnebago forum for research. Adding a roof A/C to a Winnebago is not a rare occurrence. There are even shops that specialize in doing that. The owners would be a good source of information.

The analogy I can come up with is this:

Say you own a classic Buick car. You are looking to make improvements to the running gear, but few in the Buick community had done the work. But you find out the owners of Chevy products had made the improvements.
Both the Buick and Chevy use similar components.

It would make a lot of sense to research what the Chevy owners did, and apply it to your Buick.

[MBnKen]

Great tip Norm,
I would like to get a bit more cooling to the front. Adding the extra vents sounds like the answer.

Did you ever block one of the rear vents to push more of the conditioned air to the front? I would have been afraid to do that with the current number of vents but I will try it if more vents are added.

[Norm4015]

Quote:

Originally Posted by MBnKen Great tip Norm, I would like to get a bit more cooling to the front. Adding the extra vents sounds like the answer. Did you ever block one of the rear vents to push more of the conditioned air to the front? I would have been afraid to do that with the current number of vents but I will try it if more vents are added.

I have not tried blocking a bedroom vent, but I have turned the rear fan on high to push more cooling air to the front.

[Route 66]

Newmar also installed an additional outlet and return in my 2007 DSDP.

It didn't help much. Just too much glass up front.