Roof A/C's Temp Setting

[Old-RV'er]

All - I have noticed since we have owned our Ventana, we have to set the roof a/c units at a lower temperature to get the unit cool and keep it that way. Since these have the newest "coolant" in them, is that reason.
I know the MH has better insulation in it, and way better in cold. I attribute this difference to two things. A/C's are not as good as the older units, and the new Freon being used. Our normal set temp is between 70 and 72, any warmer and the rig feels hot to us. Now I realize we are in the deep south, and it's summer, out west dryer air, but this year way hotter.

FWIW - At home we keep thermostat at 76, and that does the trick for cool. Your thoughts please.

 

[Neal]

I suggest first to take temps maybe using a IR gun or other thermometers in the coach. I find that the Dometic t-stat is around 4-5 degrees off. I wouldn't worry about the number you're setting on the t-stat but instead what is the actual temp in the coach? I also admit, for whatever reason, I keep the coach cooler than I do my house and I have to adjust when I get home in working the temps back up towards my normal for home.

 

[redbaron]

68F works well for me in the newmar and sticks/brick

 

[Tip&Tina]

We’re going to have Newmar look at the back air conditioner when we go back to the factory in April for service. The bedroom air conditioner just never gets as cool as the one up front. We have turned it down to 67 and the room constantly is at 70. Runs all the time. Very hot at night. The front one will be set at 68 and the living room area is cold!

 

[Neemer]

We have three A/Cs. I don’t know if the sensors are accurate, but I have to set the temps in the three zones differently to keep the main living area cool. For instance, if I set the zone temps the same, zone 1 (main living area) may be as much as four degrees over the set temp while the kitchen (zone 2) and bedroom temps (zone 3) are at their set temps. That scenario results in the zone 1 a/c struggling to keep up and it can’t by itself. So I will set zones 2 and 3 lower to keep them pumping cool air into the duct system to benefit zone 1. Our preferred temp in the MH is around 70 as well.

 

[AbdRahim]

We’re going to have Newmar look at the back air conditioner when we go back to the factory in April for service. The bedroom air conditioner just never gets as cool as the one up front. We have turned it down to 67 and the room constantly is at 70. Runs all the time. Very hot at night. The front one will be set at 68 and the living room area is cold!

On mine the rear is often set lower than the front. With the big windows in the front, that A/C has to work harder to maintain the temperature. It runs more often and gets the front colder at times. At mid day, I have to turn the temperature of the front up, or it gets too cold. At night, I have to turn it back down to maintain the same comfort level. The thermostat always says it is older than what my independent thermometer says.

I think the rear thermistor gets partially cool, by the front A/C so, it doesn’t run as often.
I generally just adjust the temperature to how I feel and pay little attention to the number.

 

[Neal]

I close my bedroom slider door half way to try to keep the rear AC from affecting the front zone thermistor on the wall outside the 1/2 bath. I'm sure zoning AC's in a small area is not an easy or accurate task.

 

[Old-RV'er]

Thank you all for the comments. We leave sliding door open during day. Raise rear temp setting once BH goes to bed, turn fan speed down as well. Most often she just wants it off, so I turn up front fan speed and take temp down 1-2 degrees. Will advise after nest trip and see how it worked that time.

 

[Old Bubblehead]

A/C units are designed to provide a specific Temp drop across the unit. Usually hear 20/ 25 degree difference between supply and return. I had a knock down drag out fight with Newmar around the AC units in our original coach (2019 CS 3719). In that layout, huge living area forward with bedroom aft (single midship head) the one AC could never satisfy the setpoint and the after unit short cycled due to much smaller heat load. Yes the feed the common duct work, but primarily feed the areas they service. When I ran the data, the front unit was undersized for load. the calculated total load of the coach and split it equally. Newmar would gladly upsize the unit if I paid for it. We did some deep south camping trips and the coach was always hot. We had to resort to the tricks discussed above to manage heat load in extreme heat. Was on our list to upgrade with we swapped coaches.

On new coach, Magna Shade made a difference in cockpit temps.

 

[Old-RV'er]

Yes you are correct. 25 degree difference is at the absolute tops based on exchange process in unit. New Freon's do not work as good as the old stuff for heat transference but what is a body to do. We have talked about magna shade, with the little use lately cannot justify price at this point. If we use it more will opt for one.