Class A Whole House A/C Question

[Grapehound]

We have a 2010 40 foot Winnebago Tour with a basement whole house type A/C.

With the 90 degree weather upon us, we are going on a three week trip where we will be limited to a 30 amp plug in some places.

If we use a 30 amp connection for our 50 amp service, will we still get some air conditioning? I have tried to look on various A/C threads on the forum but most deal with having two roof A/C's.

I don't know if my system has one or two compressors or how it would be affected by 30amp service. I assume it would have less coolng capability on 30 amps.

I guess if it gets too hot in the afternoon we can just run the generator for full A/C capacity.

[Jim_HiTek]

IF you have a Coleman heat pump, 'Coleman Mach' is what it says on my thermostat, then you just plug into 30 amp, and the circuitry will take care of things. It'll run one compressor of the two (yes, you likely have two) for cooling (or heating as the case may be) so what I do in that situation is find some shady spot at the RV park to help keep the heat load down. Or I'll park in a favorable direction to avoid too much sun on the living room of the RV, even if I have to park backwards in the site. Unfurl my awnings, put out my lawn chair, and have a nice brew while the basement air does it's job. Aww, the camping (glamping?) life is great.

Those Coleman's are great machines. I've lived with both the rooftop 30 amp rig and now a 50 amp basement air rig and much prefer the basement air. They do need periodic maintenance which is problematic because it's such a large piece of gear in a basement compartment, not easily removed. There are things that go wrong with them too after a few years...like the pillow block bearings go bad...I replaced mine with ball bearings a couple years ago. Then the fan motors should be lubed too. But it's an every few years thing so not too bad. Read about my work at my ad free blog: Heat Pump

There are other blogs online that help too if you decide to tackle the job. Yours is getting to that age where you should consider pulling it out for maintenance.

[Grapehound]

II do not believe my unit is a Coleman, at least it doesn't say "Coleman" anywhere. I need to research my manual to see if a brand is given.

But you give me hope that we'll have at least some cooling from the 30 amp service.

I wouldn't know where to begin to maintain it. I always wondered if a regular HVAC person could access the system to maintain it somehow but it seems buried in the rear of the coach. How do you access the system?

[Grapehound]

I just checked the manual and it is a Coleman system! Little did I know!

[Jim_HiTek]

You might follow the link I listed above. See if your's is similar. If it's a typical Class A RV with basement air, and your RV is 50 amp, note that HVAC companies will not work on it usually UNLESS you remove it from the basement compartment. Which takes some skill.

The good thing is that the electrical cables are long enough that once it's out of the cubby hole, it's still powered. And taking off the top cover gives access to all the plumbing, compressors, motors, and what not and removing the front cover (obvious what that is after the hinged basement door is lifted) gives access to all but one of the caps. Motor Start & Run caps are generally changed when doing maintenance.

[Cooperhawk]

If you have an ABC Bus shop near you they will work on it. At least the one we have will. The dropped it out and rebuilt it for us.

https://www.abc-companies.com/locations

[NCC-1701A]

I loved the basement AC in our two Journeys. It will run on 30 Amp service, as already mentioned. Winnebago's energy management system controls what's on and the priorities nicely.

[Ray Lenning]

We have the Coleman basement heat pump on our 2005 national Dolphin , when connecting to a 30 amp service it will not cool as well as on 50 amp due to only using one compressor .

[chuckftboy]

That basement air is probably rated at 30,000 btu's cooling. Running one compressor on a 30 amp circuit will give you 1/2 capacity. 15,000 btu won't cool a 40 foot coach at 90 and above. you are correct on thinking about using the generator on those day's when connected to 30 amps.

[Petro]

Grapehound;

You did not say if your 2010 Tour has the Energy Management System. I assume it does. On our Horizon I could run the AC on 30A service. I would switch the hot water heater to gas and set the refrigerator to automatic.

The Coleman Mach thermostat starts compressor one on first. After the start up load levels off it starts compressor number 2 up. With both compressors running it drew about 26 amps. When my DW wanted to run the Micro the energy management would shut the #2 compressor down and restart it when the Micro shut down. It left about 4 amps for lighting and the TV.

During the cooler night hours many times the refer would switch to electric if only 1 compressor was needed. If you have a residential refer I am not sure your Energy Management system manages it.

Experiment with it and you may find that you can keep both AC compressors running. Most power pedestals have a 15 A receptacle and I have seen folks run a power cord in and use the extra power for other needs like powering a residential refer.

Good luck and let us know how it works out for you.

Don

[Grapehound]

Originally Posted by Petro

Grapehound;

You did not say if your 2010 Tour has the Energy Management System. I assume it does. On our Horizon I could run the AC on 30A service. I would switch the hot water heater to gas and set the refrigerator to automatic.

The Coleman Mach thermostat starts compressor one on first. After the start up load levels off it starts compressor number 2 up. With both compressors running it drew about 26 amps. When my DW wanted to run the Micro the energy management would shut the #2 compressor down and restart it when the Micro shut down. It left about 4 amps for lighting and the TV.

During the cooler night hours many times the refer would switch to electric if only 1 compressor was needed. If you have a residential refer I am not sure your Energy Management system manages it.

Experiment with it and you may find that you can keep both AC compressors running. Most power pedestals have a 15 A receptacle and I have seen folks run a power cord in and use the extra power for other needs like powering a residential refer.

Good luck and let us know how it works out for you.

Don

Thanks Don! I believe I do have the Energy Management System. Thank you for this detailed explanation of how things work. You give me hope that if I run the fridge on propane and minimize other power use that a 30 amp circuit might allow the system to start the second compressor. If it does not, and it's hot, then we'll just have to fire up the generator for a hot afternoon. Thank you so much for your expertise.

[2cyber71]

My 07 Ellipse had a basement AC
It used 24- 26 amps on full AC.
So you need your fridge on gas.
Hot water on gas.
I’ve done it, but it will shed at times when you turn things on.
If you use the microwave, you will shed the AC

[Grapehound]

Originally Posted by 2cyber71

My 07 Ellipse had a basement AC
It used 24- 26 amps on full AC.
So you need your fridge on gas.
Hot water on gas.
I’ve done it, but it will shed at times when you turn things on.
If you use the microwave, you will shed the AC

Thx, 2cyber! I am hopeful that both compressors will run if we keep other electrical use to a minimum, put fridge on propane and put hot water on diesel.

[Grapehound]

Originally Posted by 2cyber71

My 07 Ellipse had a basement AC
It used 24- 26 amps on full AC.
So you need your fridge on gas.
Hot water on gas.
I’ve done it, but it will shed at times when you turn things on.
If you use the microwave, you will shed the AC

Thx, 2cyber! I am hopeful that both compressors will run if we keep other electrical use to a minimum, put fridge on propane and put hot water on diesel.