Community Forums

TallPaul · 07-18-2007, 04:28 PM

I have a 2000 28' Class C with a roof air conditoner. I can plug in at home to a 15 amp circuit and the air works fine. I never use a TV or microwave, really only a few lights and the water pump.

Is there any reason I should NOT be running the air on a 15 amp circuit? Could it damage the air conditioner?

Would prefer not having to run a 20 or 30 amp circuit to the yard.

Not sure the BTUs of this unit. Can't find the info in the manual, but it does say "Coleman Mach" by the fan switch. There is no heater on this air conditioner. The manual cover says its a Coleman Series 7000 and 8000.

I don't run it at home that much, maybe an hour a couple times a month if I am working on something.
Thanks

TallPaul · 07-18-2007, 04:28 PM

I have a 2000 28' Class C with a roof air conditoner. I can plug in at home to a 15 amp circuit and the air works fine. I never use a TV or microwave, really only a few lights and the water pump.

Is there any reason I should NOT be running the air on a 15 amp circuit? Could it damage the air conditioner?

Would prefer not having to run a 20 or 30 amp circuit to the yard.

Not sure the BTUs of this unit. Can't find the info in the manual, but it does say "Coleman Mach" by the fan switch. There is no heater on this air conditioner. The manual cover says its a Coleman Series 7000 and 8000.

I don't run it at home that much, maybe an hour a couple times a month if I am working on something.
Thanks

TXiceman · 07-18-2007, 05:22 PM

As long as all you run is the A/C you will be marginal. If you run the frig, use propane and not electric, same for the water heater. If you get a really hot day and try to restart the unit too quickly after a shut down, it will probably cycle the unit on the internal overload.

Ken

TallPaul · 07-18-2007, 06:10 PM

I don't know what the internal overload is, but I recall that for some reason, if you shut off the air and immediately back on, it will have a much larger startup draw than normal. I figure just running it should be okay on 15 amps, but that the startup spike could be up to 25 or more amps.

Actually I have a clamp on ampmeter and should do some actual testing. Then I would know for sure.

RV Wizard · 07-18-2007, 11:36 PM

Keep a close eye on the cord adapter and keep the connections tight or you could burn the prongs on the cord from arcing.

TXiceman · 07-19-2007, 03:36 AM

The internal overload on the compressor is a device called a Klixon which is usually mounted in the electrical box n the compressor. It is a simple thermal disc to open the circuit to the compressor in the event of high temperature which is caused by high amps. Some newer compressor use an internal solid state sensor now.

As RV Wizard noted, feel the 15 t0 amp adapter and if it starts to get too hot, discontinue use. The hotter it gets, the more resistance you get and then it gets hotter....kind of a snow ball effect.

Ken

TallPaul · 07-19-2007, 03:43 AM

Well hopefully if the Klixon kicks open the circuit it will go back on once things cool down.

Anyway, seems to me the plugs can get hot also if running on a 30 amp service, but I suppose the heating effect is accentuated with the 15 amp adapter.

I already had the heating effect on a poor connection in the electrical box where the solid wire line from the generator connected to the stranded wire line to the automatic switch. The wire nut was loose and melted. I found it in time. Whole story is posted in this same forum.

Thanks

Turrable Terry · 07-19-2007, 05:35 PM

My 13,500 BTU units pull around 13.5 AMPS on normal run. I can run both on my 30 AMP home setup as long as both compressors don't decide to start up at the same time. If yours is this size, you will be pushing the envelope on your setup every time your compressor comes on. I would expect on shutdown and immediate restart you could be pulling around 22-25 AMPS.

TallPaul · 07-20-2007, 07:19 PM

Terry, If your 36-foot motorhome has a 13,500 btu, they likely mine is smaller for a 28-foot motorhome. Last year I had a 32 foot Itasca ('97) and the air in that motorhome (was ducted) would kick out my breaker on the 15 amp circuit.

Prior to that I had a 1990 Damon 27' Class C and ran the air a lot plugged into 15 amps. Never had a problem. I suspect the same is the case with this 28 footer, but will keep a check on the connections anyway.

I'll have to measure the amps this weekend. Just haven't had time yet.

TallPaul · 07-21-2007, 12:59 PM

Okay, I tested the AC amps.

Just plugged in the converter is drawing 4 amps.

Kicking on the air, it spiked to (what I could see on the needle) about 29 amps. Running on high air it was drawing over 16 amps.

Now, I kicked off the breaker on the converter and with everything off there was no draw. Then I turned the air conditioner on and found the start up spiked to about 27 amps and running high air the needle was fluctuating from 12 to 13 amps.

So, a new question:

Can I leave it plugged in and run the air with the breaker for the converter turned off?

I assume all that does is not convert 120V to 12V and not charge the battery, so in effect I would be running down the battery if I were to use the pump or lights, but since it is for a short time (one or two hours), it should not matter.

Likewise, since the converter is not running, there is no need for the converter cooling fan.

The other thing is that when plugged in the outlets are running at 120 volts, but with the air on, they are 110 volts. I use an extension cord that has the 15 amp plugs but is as fat as the land line and marked #10.

TXiceman · 07-21-2007, 01:23 PM

Yes, you can turn-off/unplug the converter and run for what ever time your batteries last.

If you cord is a #10 wire, it is rated for more than 15 amps, so it should be heavy enough for the A/C unit.

Ken

TallPaul · 07-21-2007, 03:05 PM

Thanks. Now I have a working plan. Just have to remember to turn the converter back on before a trip.

Pusherman · 07-21-2007, 04:07 PM

There are 2 things to consider here:

1) Gotta have 100+ volts to make it work w/o damaging the unit. Go buy a volt meter at CW which plugs into an outlet in your coach to monitor voltage. If it's below 100V you may have a problem.

2) If the above voltage is OK, then if the circuit breaker doesn't pop (assuming it's a good breaker) then you are OK.

To be safe, make sure you run the shortest amount of cable to your plug, no smaller than 12 gauge wire, no more than 50' of extension cord.

To be totally safe regarding your a/c and other electrical equipment, buy a surge-guard unit, installed in-line to your power source. Also sold a CW.

TallPaul · 07-21-2007, 04:29 PM

Well, the wire is big enough on the extension cord, but it plugs into a wall outlet in the garage that is strung about 40 or 50 feet from the electrical service on #14 household wire.

I probably should just run a 30 amp circuit out there. Have a spare breaker from an old electric dryer 240 volt and 30 amp. Could run just one side of that breaker for 30 amp 120 volt. Wires already in conduit to garage as previous owner had converted to run an air compressor in garage, so would not be too difficult to run.

Ideally go under driveway and have outlet beside motorhome, but that's another story, A story that includes a dump drain too, which will never happen.