Running dual A/Cs at once

[Gkerlin]

I have dual A/C units - both are ducted to the same ductwork, separate zone controls for each.

My question... when I was sitting in the 95 degree heat of the Sonoran Desert is...

Does anyone know if it's ok to close the direct exhaust vents on both units so that both of them discharge the cool air thru the ducts?

Normally I run the living room unit thru the ducts, and the bedroom runs with its vents open so that it discharges into the bedroom. I've found however that if i have both units discharging into the ducts, that the air comes out a lot more force full, and the front unit helps to cool the larger living area of the coach.

My concern is that both units operating and discharging into the ductwork at the same time might be causing too much back pressure and overworking the units.

It sure seemed to cool the whole coach much better when they worked in tandem but....

Anybody out there have any thoughts?

BTW - now sitting in the cool air of Show Low Az so the A/C is off and the windows are open.

[dpilot]

you should have no problem... I have 2 15k a d do it that way all the time...
enjoy Az...!! !!!!!!!

[HOOK]

Run them both through ducts most of the time. Only open the dump doors when we want a quick cool down as when we first park in a hot place. You get a more even cool through out with doors closed. Ours works extremely well for each purpose. We only had one for our first outing and it was not sufficient. We often have 100 deg days here in the south with very high humidity. 2nd AC Required.

[DQDick]

You can adjust the dumps so we use the one in the bedroom half open and the one in the living room mostly open. That worked well for us last summer in the 113 degree weather we had here.

[mhs4771]

Run them both in the ducts most of the time, did that with the Monty and now with the SOB

[Gkerlin]

OK folks, thanks for the reinforcement. I started to play around with it the other day and was just leaving the bedroom dump open slightly and even in the desert the coach was nice and cool and the temp balanced nicely.

[Art-n-Marge]

It should not cause any damage since the force of the air for both units has a place to go which is out the ducts and into the rig. Over distance air loses strength compared to the strength coming right out of the blower (this was shown to me by an A/C guy back when I was responsible for our heavy duty Computer Engineering labs). With the other A/C so far away there isn't enough strength to cause significant back pressure and the air would prefer exiting the openings in the ducting.

[1retired06]

You can do what you want, as long as you have 50A service

[Clemson1881]

The system is designed to run both through the ducts. The air force of both pushing against each other greatly increases the discharge out of each vent. It is the most effective way to maximize your front A/Cs cooling. I installed vents with dampers on my camper. I close up the bedroom some, and the bathroom. These areas cool easier and require less airflow than other areas of the camper. That way more air comes out of the vents in the parts of the camper we need it.