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BadKarma226 · 05-12-2011, 12:37 PM

Afternoon All!

This is the second time that I have come to this site with the hopes of finding a source for parts for my trailer. Currently, this trailer has an Armstrong 10 AC unit (factory standard?) that doesnt want to work correctly. It does have a working capacitor and motor, both have been tested, and I believe the issue has been narrowed down to the power relay as it reads as an open circuit when hooked up to a multimeter. I have been to a few places around here looking for a replacement to no avail. Anyone know where I can find one? It'd be great to be able to have this in time for my trip to Virginia next weekend.

The AC works fine when you turn it on and give the fan a quick spin, but it won't start spinning by itself.

TG Twinkie · 05-12-2011, 12:48 PM

Are you saying that the coil of the power relay is reading open?

Is it just the fan that does not start and run?

Do you have access to a drawing for the control circuit?

Do you know what kind of current the fan motor draws?

Does the fan motor have a centrifugal switch?

I have a '74 Argosy which probably has the same AC unit as your trailer. There are 4 push buttons on the control panel. "OFF" "FAN" "LOW COOL" "HIGH COOL". Does this sound the same as yours?

Jammer · 05-12-2011, 01:03 PM

Probably nothing wrong with the relay. I would guess you need a new fan motor. The bearings go bad over time. There are places that have them although it may take some digging, search for armstrong here on the forums and you'll turn up many threads including some with part numbers.

**DKB_SATX** · 05-12-2011, 01:22 PM

I'm not sure this is the same AC unit that you have, but it's a detailed thread on rebuilding the unit and he's happy with the results in operation.

http://www.airforums.com/forums/f427...dor-76432.html

BadKarma226 · 05-12-2011, 03:04 PM

@TG Twinkie: It has a 4 position rotary switch with Hi/Low Cool/Fan. When turned to fan, it simply hums; If you manually spin the fan it takes off on its own. With the fan running you can switch to Cool and seems to work. The start condenser is good, the relay looks good but shows no resistance at the coil. Nothing looks or smells burned which makes me wonder if it really is bad. Could it be the start windings in the motor? How could I check those?

@Jammer: I don't think its the bearings, the fan spins with no trouble.

TG Twinkie · 05-12-2011, 04:19 PM

Is the relay 120 VAC or 24 VAC? In either case it will be difficult to measure the coil with a VOM to determine if it is good.
Do you have the unit out and on the bench?
Can you determine if there is voltage to the coil of the relay? The reason I ask is that if the fan motor runs when you spin it. I think the power relay is picking up. In most cases there is a "normally closed" contact that switches out the start capacitor within a few milliseconds and a "normally open" contact that powers the motor.
Were you able to locate a drawing of the control circuit? It may be located under the inside cover. If you could get a shot of it with your camera and post it. It will help.

BadKarma226 · 05-13-2011, 02:09 PM

It is a 120 VAC unit, will get back to you on whether or not there is voltage is getting to the coil and about the wiring diagram. Need to get a dry day before anything else can be done.