A/C Question (Impact 332)

[Niner1000RR]

First post here and first actual "RV" trailer. So maybe some noob questions coming... lol

So we bought a 2018 Keystone Impact 332 and have used it on a couple trips now. We've found that the A/C is extremely loud and it never turns off.

I've read in some groups that some t-stats have an "auto" mode, however mine does not.

So I was trying to be tricky and run the rear unit (set to a low temp) with the vent closed, pushing the air into the front cabin while leaving the main unit off (lets say for watching TV while it's raining for example). But that doesn't work because the rear unit won't run unless the front unit is running. Strange...

So I thought, if there was an "auto" mode, I could set the front t-stat high, so it would turn off leaving the rear unit running (with the lower temp not being hit yet). But with no "auto" mode, that doesn't work either.

So I guess my question is, does anyone know if something can be done so the rear unit can be run without being dependent on the front unit being on?

Or maybe swap out the t-stat with one that has an "auto" mode?

Anyone encounter this?

Thanks in advance!

[ctbruce]

9'r, welcome to the forum. Could post a picture of your thermostat? That would help us help you.

I have an Impact and both of my AC's have auto. Hmmmmmm...let's see what we can help you with.

[Niner1000RR]

I'll have to take a picture when I get home today, but it looks like this one.

https://cdn2.bigcommerce.com/server4600/584d2/products/24067/images/39013/3316255.000-1_2__08684.1508002965.1280.1280.jpg?c=2

I've heard of and seen pictures of others that look like this with an "auto" but when I cycle through the modes, I only see a fan mode (which allows for speed adjustments) then cool and heat.

I'm going to mess with it some more today.

I wouldn't mind if I could "split" them so the rear would run independent of the front, that dependency seems kind of stupid IMO...

[Niner1000RR]

Someone on facebook just pointed out that these don't work like your home t-stat does. You set the "fan speed" and it applies that to the cooling mode.

Now I feel like an idiot... haha

[chuckster57]

That thermostat is designed to control a single A/C unit. If you have two A/Cs you should have two of those thermostats and they should operate independently from each other.

If you only have one of those thermostats and it turns on both A/C units then you have the wrong thermostat. Dometic makes a “multi zone” thermostat to operate up to 4 units from one thermostat.

[Niner1000RR]

That thermostat is designed to control a single A/C unit. If you have two A/Cs you should have two of those thermostats and they should operate independently from each other.

If you only have one of those thermostats and it turns on both A/C units then you have the wrong thermostat. Dometic makes a “multi zone” thermostat to operate up to 4 units from one thermostat.

That should be correct, however... The rear A/C will not operate unless the front unit is running.

As strange as that sounds, if I turn off the front unit, the rear one shuts off. The t-stat ironically will say that it is still on "cool" at whatever temp I have set. But the unit won't be running.

[ChuckS]

Curious as to why Keystone would wire up AC units to one control.

This is listed as stock thermostat for your unit .....
http://www.trekwood.com/products/1161509/A-C-Thermostat-CT-Heat-Cool-Black-3316250-012-Dometic

Wonder why they did not install two of these so you can separately control the units or why they didn’t install CCC2 multi zone Dometic control unit.

Absurd that you have to run both ACs at same time.

[Niner1000RR]

Curious as to why Keystone would wire up AC units to one control.

This is listed as stock thermostat for your unit .....
http://www.trekwood.com/products/1161509/A-C-Thermostat-CT-Heat-Cool-Black-3316250-012-Dometic

Wonder why they did not install two of these so you can separately control the units or why they didn’t install CCC2 multi zone Dometic control unit.

Absurd that you have to run both ACs at same time.

I couldn't agree more sir! When I had first tried it, I figured, huh... Must have tripped the breaker, odd. So I checked it. Nope, breakers are all good. Strange.

Tried to cycle the t-stat off and back on. Nothing. Oh no, doesn't seem good for a brand new trailer. Turned it off, turned the front one on. Went back, tried again it worked.

Went to the front unit, turned it off and BOTH units turned off. WTF?!?!

I'm not even sure how they would do that. As an electrician by trade, sure it's possible, but you'd have to go out of your way to run a cable between the units, for no other reason than to do this.

The only reason I could see for doing it would be to prevent you from accidentally leaving the rear unit on. In this case, you could turn the front off (say to leave) and it would kill both.

That's the only thing I could think of. But if so, I want to undo it! lol

[chuckster57]

As an RV tech, I’m more inclined to think something was done along the way between the factory and delivery to you.

Your unit is surely 50A service, and needs said service to properly operate both A/C’s. If you use a 50/30 adaptor, your asking for trouble running both.

Does your unit have an onboard EMS? I can’t in all good faith believe the factory would build a unit that didn’t have the ability to operate one or the other or both, doesn’t make sense.

[Niner1000RR]

As an RV tech, I’m more inclined to think something was done along the way between the factory and delivery to you.

Your unit is surely 50A service, and needs said service to properly operate both A/C’s. If you use a 50/30 adaptor, your asking for trouble running both.

Does your unit have an onboard EMS? I can’t in all good faith believe the factory would build a unit that didn’t have the ability to operate one or the other or both, doesn’t make sense.
It does have a 50A service. Which I use. It does not have an onboard EMS.

If I tried to run both units on a 20/30A service, if the breaker was sized to the wire size properly, it would merely trip the breaker.

I'm gonna pull it off the wall and take a look at what they did. I agree, it seems crazy!

[ChuckS]

So they installed this single zone thermostat and wired both control board 12 volts lines to one thermostat.

https://cdn.ltvdns.com/leisurevans.com/owners/3rdparty/Dometic-Thermostat.pdf

I don’t see why you could not upgrade to CCC2 multi zone thermostat and replace that single control unit with multi zone and wire control wires accordingly for each unit.

It would beat option of trying to install another single zone thermostat for other unit and fish the wires

I also wonder if your unit has TWO remote room temperature sensors mounted? One in bedroom and other in living room areas

If not then you have two issues to deal with... and if RV don’t have the two separate remote temp sensors this explains why they installed a single zone thermostat.

[Frank G]

First of all Welcome

A couple of thoughts, was this a dealer installed option?

I noticed the second unit gets installed in the garage and from the Keystone Literature showing one AC in the main living area the thermostat is located in the garage. Are there any issues about running a AC in the garage and the possibility of pumping deadly fumes to the living area?

Personally, I think the multi unit thermostat is in order.

Lastly, not all AC units are created equal, some are nosier than others. In our last THTT there was no TV with the AC running. sad

In our present unit we have 2 AC units and operate them as described in the OP's first post.

[chuckster57]

In our present unit we have 2 AC units and operate them as described in the OP's first post.


What your saying is if you turn in one AC unit, both operate? You can’t turn one off?

[xrated]

Switching to the Multi-Zone thermostat CCC II is not just a matter of changing thermostats. The Single Zone has three wires running to it...+12VDC, -12VDC, and the Comm or communication wire which is orange. The CCC II uses a 4 wire setup involving telephone type connectors....probably the RJ11 type connectors...plus the control boxes in the A/C units are different.