coleman a/c

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yukon3506

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Jun 30, 2006
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wiley ford, west virginia
i have a 97 fleetwood terry that has a coleman a/c, the man i bought it off of said the trailer needed a new thermostat and the a/c would work fine. Today i installed a new thermostat and the a/c still just blew warm air, i let it run for 20 mins and it never sounded like the compressor kicked on. Does my unit need recharged or is something else wrong i'm just not seeing? And if it does need recharged can this be done by myself like a auto or does it need to go in to the shop? any help would be great. Thanks a million in advance
 

Gary RV_Wizard

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A couple of possibilities:
(1) If the compressor never came on, either the thermostat is not signalling for "cold" or the a/c's control board is not hearing the request. You need to figure out which it is (or get it to an RV a/c tech who can do so). A new control board is expensive, but not not more than the a/c is worth (assuming it is otherwise healthy).
(2)The new t-stat is not compatible with RV systems. Is the new one an exact replacement or did you try a house-type thermostat? Most house-type t-stats won't work in an RV.

It should be fairly obvious if he compressor tries to start - it's a much deeper hum than the fans.  Lack of refrigerant won't inhibit it from trying to start but it might make the start-up unsuccessful. You would notice that - here would be a deep hum for 15-45 seconds and then it would stop, without the compressor coming on. I doubt if freon is your problem, given what you have described.  And no, it is not refillable at home - they are sealed units.  And if it did need freon, then it has  a leak. Given the age of it, it would be more cost effective to replace the a/c then to get th eleak repaired and the system re-charged.
 

woodartist

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Another thing to check is the start capacitor for the compressor. Easiest way is to do a substitution, however you can remove it and have it checked at an AC place.....
 

Karl

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Gary,
It's not often that I disagree with you, but a low refrigerant charge will normally allow the compressor to run with very little additional sound above that of the fans/blowers, but no cooling will take place. Some a/c's, particularily automotive systems, will not even try to engage the compressor if the refrigerant charge is too low. A system that cycles on and off within the times you mentioned, without actually starting the compressor, usually indicates a too high head pressure, which must be relieved before the compressor motor has enough energy to overcome the starting resistance.

Yukon3506;
If the problem is a low refrigerant level (a leak), there's nothing you personally can do about it. It's a sealed system, and without the proper tools/gauges/brazing equipment, there's little you can fix yourself. As Gary said, if it is a leak, you're better off replacing the unit than trying to apply bandages to an old wound. If you're comfortable with electrical circuits, you could try jumpering the thermostat to see if the a/c is working or not. It's not difficult, and the voltages you'll encounter will be in the 12 volt range - pretty much harmless. May be worth a try, and you may save yourself a few hundred dollars (if it's the thermostat).

Good luck! 
 

Gary RV_Wizard

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It's not often that I disagree with you, but a low refrigerant charge will normally allow the compressor to run with very little additional sound above that of the fans/blowers, but no cooling will take place.

I can't disagree with that, Karl, but in my experience it's uncommon for the refrigerant to be so low there is no start-up compression at all.  But I can't claim my experience is extensive, either.
 

King

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What model Coleman?  I have a Coleman Mini Mach 7500BTU and it doesn't connect to any separate thermostat.  All the controls are in the unit.  There is off, lo fan, hi fan, ac with lo fan, ac with hi fan.  There is also a continuous control with cooler clockwise.
Art
 

yukon3506

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Jun 30, 2006
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wiley ford, west virginia
Thanks again for all your help,I went up on the roof and took a look at the a/c to try to see if the compressor was kicking on or not but of course only the fan would run and it looks like somebody already has tried to charge this system because of a saddle valve on the low pressure side of this unit, i put a pressure gauge on the fitting and it showed 0 so i guess it either has a heck of a leak somewhere or is leaking out of the valve itself. I'm looking at a new  Coleman 15,000 BTU unit to replace this one, has anyone used this unit yet? could you suggest something better or give me any helpful hints on installing this new unit. Thanks again for all the help.
 

Karl

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Yukon,

Finding a saddle valve is not a good sign. There is probably a leak in the system; maybe slow, but a leak nonetheless, and even if the it had been fixed, the saddle valve, not being designed for the 200-250 psi pressures encountered in operation, has probably given up the ghost. Also it's likely the person doing the band-aid fix didn't properly evacuate the system before recharging it, so moist air entering it has probably caused internal corrosion. IMHO, don't throw more money at it; replace.

Coleman units have been used in rv's for many years and are a good quality unit. I don't have any first-hand knowledge about the 15kbtu model, but for the small additional price, I would choose it over the 13.5kbtu unit. It draws slightly more at full load (16A vs. 14.5A) but that's not much of an increase.
 

Gary RV_Wizard

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Dometic has a "high efficiency" model that draws around 10 amps.

And Coleman has a 7700 btu Mini-Mach model tha works great in small campers.

choice of Dometic (Brisk Air) or Coleman is a toss-up - both make excellent units.
 
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