Help Needed: Basement Air Problem

[gfs1943]

Basement air conditioner quit working on our 2000 Itasca Horizon. AC blower works. Compressors run, but condensor blower doesn't run. It will sometimes start and run a few seconds, then shuts off. Compressors continue to run until (probably) the high-pressure switch shuts them off because there is no cooling air. Sometimes when I turn on the AC, nothing runs except the inside blower. Sometimes, it works as described above.

The condensor blower spins freely, so it's not bound up. I suspect a circuit board problem, or a sensor switch problem, but can't say for sure. Any help appreciated.

[Ozlander]

That is interesting.

[gfs1943]

UPDATE: I made an appointment with a service facility to let them look at the AC. I brought the coach to the house yesterday, to prepare for the trip to service facility today. I decided to give it one more look myself.

I got the correct documents for my AC model from the Airxcel site. There is an 8-amp fuse inline in the condensor blower high-speed wire. That fuse was blown. I replaced it and everything now works correctly. I cancelled the service appointment this morning.

That fuse is optional, and not shown on all the wiring diagrams, even for my model. Apparently, what happens is that the condensor fan motor has two totally seperate circuits for high and low speeds. When the thermostat set point is one degree lower than ambient, only AC circuit #1 is called for and the condensor fan runs on low speed. When the thermostat set point is two or more degrees below ambient, both cooling circuits #1 & #2 are demanded. The condensor fan low-speed circuit shuts off, there is a brief delay, then the high-speed circuit is activated. Since the fuse was blown, there was no high speed available so the fan just stopped. If the inside ambient temperature dropped to within one degree of the thermostat set point, the high-speed circuit dropped out and low-speed was re-activated. That would make the condensor fan come on again. Strange way to setup a fan, but I guess it was designed to minimize electrical load.

Thanks to all who replied and helped me with this problem. I hope this info helps someone else with a problem someday.

[azpete]

almost every time, when its not starting right, its the start relay. go figure?
do the diagnostics using the service manual which is available on line.
the part cost about 40 dollars, and can be ordered on line or at most rv repair shops.
get the model number, serial number and any other numbers on the identification plate. this will help ordering the right part.

[gfs1943]

UPDATE: Got home without too much trouble. Spent a couple of days in Vicksburg; temps very pleasant and the AC unit worked part of the time. Spent Friday night in Shreveport; it was miserable. Hot and humid, and not much breeze. The AC wouldn't work a minute.

Drove on home on Saturday. As soon as I hooked up to electric at my house, I turned on the AC and it would run about 75% of the time. The condensor fan still is intermittent. I'm gonna try replacing the relay(s) and all the capacitors as soon as I can get them. Will post update when I become an expert on this system!

[gfs1943]

MeanderMan wrote:
I had a capacitor go bad and short out, taking the circuit board with it. I replaced both the capacitors and the board, and my unit did the same as yours. I replaced the relays and it solved the problems. I'd try that first, they're only about $10 each if you order direct from Airexcel. They're easy to replace, located right above the circuit board on my model.

I don't find any "order parts" link on Airexcel's Web page. Can you provide a link, or send me a PM with ordering info? Thanks a million for your help.

[MeanderMan]

I had a capacitor go bad and short out, taking the circuit board with it. I replaced both the capacitors and the board, and my unit did the same as yours. I replaced the relays and it solved the problems. I'd try that first, they're only about $10 each if you order direct from Airexcel. They're easy to replace, located right above the circuit board on my model.

[Bikeboy57]

Sounds like the start capacitor is bad on the condenser fan. Common failure. No different than a home AC.

[427435]

The biggest issue is getting to the unit. I took mine out to look for a noise (copper pipe from the compressor was hitting the blower housing and making a racket). I happened to have a low workbench (for my kids) that was about the right height. Remove the outside panel and then crawl underneath. There are a number of screws that hold the vertical air duct in place. Remove them (a cordless drill is a big help. Remove a couple of screws under the unit, and the whole unit can be slide out onto a work surface (saw horses might work too). There is enough electrical cable to allow you to slide it out without unhooking any electrical stuff. Once out in the open, any house AC service man should be able to work on it.

[ferndaleflyer]

Mine is also in the basement and although I have never had any "problems" I have had it checked or should I say serviced by the same person that does our house every spring. He says its nothing more than a "package" unit. Mine is about 15 years old now.

[teamfossil]

I also have a 2000, although mine is an Adventurer. Yeah, it's just like what you would find in any Motel 6, though you will play heck getting it fixed at any RV dealer. If it ain't on the roof, they are lost! They are made by Coleman, and RV Products (Airxcel) in Wichita, Ks is the manufacturer. When you find someone to work on it, you'll probably find it's a relay, although there is an upgraded circuit board. It sounds like everything is working (except that relay) and access is good. Lift up the cover, get a comfy chair and have at it. It's pretty much "plug and pray" and the people at RV Products where very helpful. Once I replaced the circuit board (4 years ago) mine has been great!

[Fishinghat]

Since most electrical problems can be traced back to a weak or faulty ground, that's where I'd start looking. Find and clean all of the grounding points.

Our basement air units are rather rare since most coaches have roof air. However, my basement A/C looks amazingly like a regular household system, so perhaps a heating/air conditioning service company could diagnose the problem and suggest a repair or even actually repair your unit.