Refurbing the Original Air Conditioner

My Airstream came from the factory with an Armstrong Bay Breeze air conditioner. Whereas today’s RV air conditioners are a single unit which sits on top of a 14-inch square hole in the roof, the Armstrong unit of this era has an inside part, and an outside part. There is a three inch hole for the power & Freon line to pass through, and another one inch hole in which one shaft of the double-shaft fan passes through into the interior.

Although I had no reason to think it would still work after a 23 year hiatus, research indicated that the unit was constructed with commercial grade parts, some of which were still available, and that the unit was worth saving. Between that, and the fact that I would have to make my own 14-inch hole in the roof to accommodate a modern day unit, I set out to repair the unit.

Making sure the two thermostat wires were not touching (the thermostat, along with everything else in the control area, was currently sitting in my Shop) to keep the compressor from cycling on, I switched the fan motor on, and was greeted with a loud hum, but no spinning fan blade. Going top side & removing the cover, the fan motor was found to be rusted in two after years of being covered by wet pine straw. The motor mounts had also been rendered unusable. The general appearance of the compressor did not brighten my day either.

Forging ahead, the wires going to the fan motor were snipped & capped so the compressor could be tested without the bisected motor dragging the circuit down. Returning to the thermostat wires, I jumpered them together and was rewarded with the sound of a compressor running. Knowing that running, and cooling are two different things, I maintained my composure until I touched the evaporator coils. They were cold! I ran outside & up the ladder – The condenser coils were hot! I declare I heard the Mormon Tabernacle Choir sing at that moment.

Service and Trouble Shooting Guide

Fan motor, P/N 3213010002, Redmond CY 6
Condenser fan, P/N 463-13, 14" dia.
Filter pad only, P/N 601-01, Scott Foam

So, at this point, all I have to have is a new motor. Maybe some Freon; But that determination could wait.

While I already knew that Armstrong had been out of business a long time, an Internet search provided the obituary for The Redmond Electric Motor Company. So, armed with information from both the unit's spec tag & the original Service and Trouble Shooting Guide, I visited an extremely helpful, local motor shop.

The man at the counter got the biggest kick out of that rusted-in-two motor. All in fun, he advised me that it "looks like warranty work".

Examining the motor's remains, he determined the last piece of information I did not have - the operating speed of 1075 rpm. Checking the books, he found A. O. Smith Electrical Products Company's Stock number 105 motor was identical in electrical characteristics, form & function. The only modification needed for "fit" was trimming the motor shafts to the correct length. Also, #105 is a three speed motor, whereas Redmond's motor was only a two speed. A wire cap on the "medium" speed wire resolved the issue. He was impressed with the way my motor mounted, and shared some war stories of how poorly RV A/C makers do it nowadays.

My condenser fan itself was okay. But a chunk of it's mounting hub had rusted away, and the two were manufactured as an assembly. Fearing the worst, I replaced the fan assembly. Nowadays, fan blades are screwed on to the hub. The man at Kelsey Electric Motor determined the blade pitch to be 23 degrees CCW.

The next challenge was dealing with the damaged motor mounts. Basically ¼-20 studs, at Armstrong’s factory, they were installed from the bottom on the rooftop unit. Removing the unit to replace them was out of the question because it would mean breaking Freon lines & removing, from all accounts, and incredible number of rivets.

Perusing my ever growing supply of spare parts, it appeared the elevator bolts left over from aft decking replacement might work with minor modification. Since the motor sits on the mounts, as opposed to hanging from them, the fasteners are there more to keep the motor from bouncing around while on the road, and keep the interior motor shaft aligned with the hole.

Grinding away the remains of the old mounts left four reasonably smooth areas big enough to accommodate the heads of the elevator bolts. JBWeld was then used to hold them in place.

Talk about cold air! That 37 year old air conditioner was all but blowing ice cubes into the interior. Adhering to the if it ain’t broke, don’t fix it rule, I scrapped plans to have a refrigeration specialist come out & check pressures.

The A/C's dust filter had...turned to dust. While I probably could have found a more exact replacement filtering element, I had already purchased something suitable to rebuild my kitchen's exhaust fan filter.