Getting the AC right

[coteyr]

So we got a new to use Grand Design Imagen Travel Trailer with a bunkhouse. We love it. We are still working on and solving problems that come up but one that is causing us a bunch of discomfort right now that we can't seem to get a handle on is the AC and its temperature.

Ideally, we would like it to be 74 all over the trailer. In the main area, the BH and the main bedroom. Now we do understand that we may not be able to get that kind of precision, but we we have now is uncomfortable.

We have 1 AC unit in the main area that is "ducted". There are vents in the bedroom, bathroom, kitchen, and bunkhouse. So far we have not been too hot. Quite the opposite.

The thermostat is set on 74, seems a good place to start as that's the temp we want. In the kitchen it's 70 in the master beedroom it's 64, in the bunk house it's 68. I don't want to know what the bathroom is, it's downright cold)

So, seems like a no brainer, just set the thermostat to 78 and be done with it. But no, if I set it to 78 then the kitchen area gets up to 78 while the other areas stay quite a bit colder.

It seems like a good answer would be to restrict the vents in the colder areas and "open" the vents in the warmer ones until everthing equals out, more or less. But the vents don't close or baffel (except the one on the AC unit it's self that cools that main area very quickly), Are there vents that can baffle in the other rooms and are they safe to use? If not, how can we achive a more or less simular tempature throughout the TT?

[miltvill]

My AC had a fan position that would run the AC fan when the compressor cycled off. It made a big difference in circulating the air. One fan or more could even out the temp.

[spoon059]

My experience is that RV thermostats aren't very precise. Set it for 74 degrees and it will keep it within +/- 3 or 4 degrees. That's up to an 8 degree swing in the temperature that it calls for. Then you factor in balance load on the ducts (there isn't any) and cooling demands. Depending where the sun is, where the insulation is, where the slides are, where the windows are, etc you're going to get unbalanced temperature control.

We find that one night we can set the AC at 72 and be freezing and need blankets, and the next night at 72 we're both so warm that I eventually get up and adjust the thermostat. Same campground, same spot, same people... wild swing in temps.

We keep our fan turned to ON instead of AUTO to keep circulating air. That helps. Perhaps a good quality circulating fan to help move air around will help balance.

[Bumpyroad]

coteyr wrote:

MFL wrote:

Bumpyroad wrote:
your main area AC sounds like it is set to a dump position to rapidly cool off the main area, then you should close the vent a bit and duct to the rest of the RV.
bumpy

This, and also thermostat location is usually in a spot to benefit all rooms in trailer. Also the vents should be located and able to rotate to best advantage. I have a round ceiling vent just outside my bathroom door, that can rotate as needed, for bathroom, shower stall, or bedroom.

In a thread in tech section, Doug mistakenly said "All trailers 27' or more need two ACs PERIOD". I corrected him, and said MANY, as there is just too many factors in design/installation to make a statement that is not credible.

Jerry

Yeah it gets plenty cold with just one AC unit. I just need to move the cold around better.

does your AC have a "dump" position where it dumps most of the air directly out of the AC and little to the other ducted ceiling vents. if so, only have that open when you are initially cooling of the RV. then once the living area is cool, shut the "dumP" feature and adjust the other ceiling vents to properly distribute the air. I would not expect much precision in cold/heat distribution in a RV, certainly not as good as in a S&B.
bumpy

[coteyr]

MFL wrote:

Bumpyroad wrote:
your main area AC sounds like it is set to a dump position to rapidly cool off the main area, then you should close the vent a bit and duct to the rest of the RV.
bumpy

This, and also thermostat location is usually in a spot to benefit all rooms in trailer. Also the vents should be located and able to rotate to best advantage. I have a round ceiling vent just outside my bathroom door, that can rotate as needed, for bathroom, shower stall, or bedroom.

In a thread in tech section, Doug mistakenly said "All trailers 27' or more need two ACs PERIOD". I corrected him, and said MANY, as there is just too many factors in design/installation to make a statement that is not credible.

Jerry

Yeah it gets plenty cold with just one AC unit. I just need to move the cold around better.

[coteyr]

2oldman wrote:
Where is the thermostat?

across from the door near the main "control panel"

[coteyr]

bpounds wrote:
No expert here, since we rarely ever use our RV A/C. But I'll throw in anyway.

No harm will be done if you restrict, or even close, any duct registers you choose. Within reason of course, but the vents on the bottom of the A/C itself should be plenty of flow by themselves.

Do you have the round registers, or rectangular. I haven't seen the round ones with flow restrictors, but there might be. The rectangular type usually do have them. But regardless of what type, you can easily restrict the flow. Just block some or all of the slots in the register. Use whatever type of tape that suits your décor preference.

If your goal is more even temperature throughout, the key is usually to push the air to the farthest ducts, and force it to flow back to the return at the main A/C. It's called Forced Air. Ideally the air flow should pass the thermostat location. And that is why they are most often placed in a hallway. So maybe you want to restrict the discharge on the bottom of the A/C unit, and open ducts in the bedroom.

I have experience with a new home and A/C where the bozos stuck the thermostat in a dead end of a hallway. No air flow. It must have been an easy place to pull the wires, because it was a stupid place for the stat. I moved it.

I think that is what is happening here. The stat is near the door and it is warmer there.

[coteyr]

jdc1 wrote:
Are you sure those other vents can't be closed off some? The round vents push in and pull out. If they are non-adjustable rectangle metal, just replace them.

These vents do rotate but they do not close. I will try covering them some till I get it right.

[dodge_guy]

Your thermostat is either faulty or in the wrong location. If set for 74 it should turn off at 74 (or at least the compressor would cycle).

[bpounds]

A small fan can go a long way to recirculate air evenly around a space. And these A/C are so noisy, you probably won't even notice a small fan.

[MFL]

Bumpyroad wrote:
your main area AC sounds like it is set to a dump position to rapidly cool off the main area, then you should close the vent a bit and duct to the rest of the RV.
bumpy

This, and also thermostat location is usually in a spot to benefit all rooms in trailer. Also the vents should be located and able to rotate to best advantage. I have a round ceiling vent just outside my bathroom door, that can rotate as needed, for bathroom, shower stall, or bedroom.

In a thread in tech section, Doug mistakenly said "All trailers 27' or more need two ACs PERIOD". I corrected him, and said MANY, as there is just too many factors in design/installation to make a statement that is not credible.

Jerry

[Bumpyroad]

your main area AC sounds like it is set to a dump position to rapidly cool off the main area, then you should close the vent a bit and duct to the rest of the RV.
bumpy

[2oldman]

Where is the thermostat?

[campigloo]

Use clear packing tape until you figure out configuration that works. Closing/restricting should help

[bpounds]

No expert here, since we rarely ever use our RV A/C. But I'll throw in anyway.

No harm will be done if you restrict, or even close, any duct registers you choose. Within reason of course, but the vents on the bottom of the A/C itself should be plenty of flow by themselves.

Do you have the round registers, or rectangular. I haven't seen the round ones with flow restrictors, but there might be. The rectangular type usually do have them. But regardless of what type, you can easily restrict the flow. Just block some or all of the slots in the register. Use whatever type of tape that suits your décor preference.

If your goal is more even temperature throughout, the key is usually to push the air to the farthest ducts, and force it to flow back to the return at the main A/C. It's called Forced Air. Ideally the air flow should pass the thermostat location. And that is why they are most often placed in a hallway. So maybe you want to restrict the discharge on the bottom of the A/C unit, and open ducts in the bedroom.

I have experience with a new home and A/C where the bozos stuck the thermostat in a dead end of a hallway. No air flow. It must have been an easy place to pull the wires, because it was a stupid place for the stat. I moved it.