2003 Winnebago Coleman Basement AC

[Petesflhtk]

At 86 outside I am thinking 72, 73 is reasonable..and comfortable...not sure what the max cooling temperature would be as insulation would play a roll in attempting to maintain a large temperature variation.

[Roger3]

New information

Took the motorhome for a short trip this past weekend. Track we stayed at had a 50amp hookup.

AC ran perfect, no short cycling. With thermostat set at 65F, unit cooled down to 69f at which time I turned thermostat higher because it was getting too cold inside to sleep.

I set thermostat to 74f and it cycled in a normal manner and keep inside temp between 73f and 75f.

Would or should operating on 50amp service make the AC system perform better?

This makes me believe the system is not low on freon. Do you agree?

I still haven't had the time to remove the AC unit and clean it. I am thinking maybe additional power needed to overcome dirty coils made it work correctly. Any thoughts?

Thanks

Roger

[stik]

Originally Posted by Roger3

New information

Took the motorhome for a short trip this past weekend. Track we stayed at had a 50amp hookup.

AC ran perfect, no short cycling. With thermostat set at 65F, unit cooled down to 69f at which time I turned thermostat higher because it was getting too cold inside to sleep.

I set thermostat to 74f and it cycled in a normal manner and keep inside temp between 73f and 75f.

Would or should operating on 50amp service make the AC system perform better?

This makes me believe the system is not low on freon. Do you agree?

I still haven't had the time to remove the AC unit and clean it. I am thinking maybe additional power needed to overcome dirty coils made it work correctly. Any thoughts?

Thanks

Roger

After reading through all the posts, and then this last one I have 2 thoughts:

1) Your basement air is running/performing fine
2) If it runs/performs fine on 50 amp shore power but doesn't on generator power, well, I think I know where I would start looking and it wouldn't be the basement air, just sayin'

[1ciderdog]

I think mine runs the same on both 30 & 50 amp power.

[John Hilley]

I would check the 120 VAC wire connections on the generator and in the transfer switch to make sure they are tight. Also check the AC voltage of the generator, sounds like the generator is the weak link in the cooling.

[bizee]

We have this basement AC setup and YES a 50amp service is a must to use both compressors! It is a two stage system as I'm sure you've seen by now and on your amp panel it will only light up the second stage full time if you drawing from other systems on 30amp or less. Stage one works on 20 amp service and will pull around 14 amps. The second stage will only work when your panel is set to 30 or 50 amp. It will pull another 14 amps or so... total is around 25 to 28 amps when both running. So even with 30 amp service is can be dicey to get that 2nd stage available the whole time because the fridge draws 4 to 6 amps, which puts you over 30 amps.

On stage one only if it is warm outside (which is must be very warm if it was 90 inside) will not drop the temp by more than a few degrees on the thormostat even if it is running nonstop. With both running if it is around 100F outside in the sun it will get the thermostat down to around 80F to 82F running nonstop but no lower. The thing is 80F inside feels a lot colder (like too cold!) because the vents blow the cold air on you that is way colder than the 80F that the surface of the walls are.

The big thing is the color of your coach. If it is dark paint it will be tougher to cool. Ours is white mostly and so far the two stage basement system has never failed to make the interior comfortable even sitting through 110F days in the desert.

You need to be running the genset or hooked up to 50 amp to get max cooling from these basement ACs, otherwise you are likely running single stage only and at best both stages intermittently.

[Duner]

With only one compressor running, 14 amps is about right. But that 14 amps is running the big outdoor blower motor, the indoor blower motor, and the 1st compressor motor. When the 2nd compressor kicks in that adds just one more motor and around 7-8 amps more for a total of around 22-23 amps (assuming the volts stay 115 or more. You may see as much as 28 amps, but then the voltage may be closer to 105.

All the motors are induction type that pull more amps when the voltage is lower because they are trying to maintain design speed (rpms). So if there is a voltage drop problem, the issue compounds itself by pulling more amps, therefore lowering the voltage even more. At low voltage, the motors run hot, the startup time takes longer stressing the capacitors and relays.

My basement unit runs fine on 30 amp service, with about 7 amps available for tv, sat, residential fridge, computers, lights and float charging the batteries. And if I run the microwave, power management sheds compressor #2 for 5 minutes.

We are happy campers on 30 amp, if the voltage is good and stable.

[1ciderdog]

Mine seems to pull 24 amps when the AC is working hard. I have not had any problem on a 30 amp circuit. But I do have an autoformer type surge protector that boosts power by 10% if voltage drops below 115.

[DAN L]

Originally Posted by Roger3

Dan,

Not sure which relay jumper wire you are talking about. Can you see it in the photo? Let me know if its one of those?
the 2 black boxes in the upper right of your pic.
mfg potter& brumfield pn. T92P7D22-12.
this is my 4th attempt to post this info, a pita for sure.

Thanks

the 2 black boxes in the upper right of your picture. mfg potter& brumfield pn. T92P7D22-12

[Duner]

Originally Posted by 1ciderdog

Mine seems to pull 24 amps when the AC is working hard. I have not had any problem on a 30 amp circuit. But I do have an autoformer type surge protector that boosts power by 10% if voltage drops below 115.

ciderdog, your 2004 came with a metal squirrel cage for the outdoor blower. I had to replace mine with the newer composite plastic version. It is much quieter and takes about 1 amp less power.

I too have an autoformer and usually see around 121 volts, with 110 being about the lowest. If it's lower than that, I usually find the 30 amp socket is worn out and over heating (as in burning up) my 30-50 amp adapter plug. When the CG replaces the 30 socket, back in business.

[1ciderdog]

[QUOTE=Duner;2800266]ciderdog, your 2004 came with a metal squirrel cage for the outdoor blower. I had to replace mine with the newer composite plastic version. It is much quieter and takes about 1 amp less power.

Duner, I did not purchase this RV new so perhaps a previous owner changed the squirrel cage. A year or so ago I pulled the unit and replaced a bearing. The squirrel is plastic.

[Roger3]

Originally Posted by John Hilley

I would check the 120 VAC wire connections on the generator and in the transfer switch to make sure they are tight. Also check the AC voltage of the generator, sounds like the generator is the weak link in the cooling.

John

Where is the transfer switch located?

Thanks I'll definitely check these along with the 120vac connections inside the AC unit.

Thanks

Roger

[KIX]

Originally Posted by Roger3

John

Where is the transfer switch located?

Thanks I'll definitely check these along with the 120vac connections inside the AC unit.

Thanks

Roger

The transfer switch will be located at the coach end of the shore power cable. The box will also have input from the generator and a cable going to your circuit breaker distribution box. Mine is located on the back wall of the compartment where shore cable enters the moho.

[Ray,IN]

Bells rang when you said the return air filter was missing. That means all the lint and dirt in return air was being deposited on the evaporator coil fins. That makes a huge difference in heat transfer. Next time you pull the unit, follow Duners instructions and clean the fins while in there. Use a fin comb to straighten any bent fins, as that too reduces heat transfer.

I use Filtrette brand air filters. Yes, they are more restrictive, but- they catch almost all airborne dirt. That requires an air filter change at least monthly when MH is used full-time. Sure it's more expensive, but I suffer less effects from asthma and COPD. Our MH windows are never opened, the basement unit runs nearly all the time because of that. It's a good thing new units are available.
As to amp-draw, the data sheet has the info.

[jerichorick]

Originally Posted by Roger3

I just bought a 2003 Winnebago Journey DL 34H. It has the Coleman Mach basement AC and heater system. I have some questions about the AC unit that I need help with. Please let me know if I should be posting this in another section of the forum.

Things I know:

1. 1st owner had the AC circuit board replaced in 2009.
2. 2nd owner had the thermostat replaced in 2013. Receipt for this work shows the AC system was checked out and says "AC Unit has full 30 amps". Not sure what this means but its what the receipt says.
3. I just bought the motorhome a couple weeks ago and AC doesn't blow cold at all. Left AC on for 4 hours cooled motorhome from 90F down to 86F.
4. Generator panel shows AC unit is pulling around 13 amps with AC on (everything else is off).
5. I pulled cover off ac unit and found 3 burnt wires. Repaired all 3 wires, now generator AC unit is pulling 21 to 24 amps with AC on (everything else is off).
6. AC unit is still struggling to cool of the motorhome. AC cooled motorhome from 99F down to 80F in 3hrs. For first 2 hours the AC system ran non stop getting it down to about 85F. Then for the next hour the AC system would cycle about every 5 to 10 minutes. The compressors would shut off but the fan would continue to blow, then the compressors would come back on for about 10 minutes then shut off. Is this normal? Or should the compressors and the AC unit continue to run until the motorhome is at 72F (where I had thermostat set).

Sorry for the long post.

Thanks for any help.

Roger

Roger, I had a '05 Vectra. Twice the plenum going up the back right came apart. This is a common problem. When running the A/C look for a moisture line on the rear cap of the coach. Also feel if air is blowing from that area but don't confuse it with the A/C unit discharge to the ground. When you pull the filter you can see the exchange. If it is dirty buy some A/C cleaner spray and wash it down.

I never did get good cooling in 90*+ weather, and in TX we did nothing but sweat. Hope this helps though it may not be good news.

Rick Y