Mach 8 AC failure. Murphy is still following me around.

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SargeW

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o we had to be in Phoenix AZ for a few weeks to take care of some medical stuff. Just before arrival, the squirrel cage on the front AC blew up. This is the second failure as the mid AC blower wheel failed and was replaced about 2 years ago. We were inside when that one blew, so I immediately turned it off and later replaced the blower fan when I could get one.

This time we were gone for a few hours shopping and in 114 degree heat leaving at least 2 AC units on and the generator auto start enabled is SOP when leaving the rig. Upon return we heard an unfamiliar "rumble" when we walked in. I figured it was coming from the AC and turned it off. I went up to verify my suspicions, and sure enough the squirrel cage was in pieces, totally broke apart. Not one piece remained together. It took a couple of weeks to get another blower wheel delivered, and I put it in easily. When the AC was turned back on the new fan blew hard, but no cool air.

Hoping it was just a start solenoid or pressure switch I switched the solenoids from the middle AC that was working to the front AC. Still no luck. Time to call the repair guy. A mobile tech came out to the campground and found in minutes that the compressor had no Freon in it. Apparently when the fan blew, it ran so long with an unbalanced shaft that the seal eventually failed and leaked out the Freon.

Mach 8 units are about impossible to find (especially in AZ in the summer) and according to the tech the particular type of Freon that they use is no longer sold in this country after Jan 1 of this year. Not that they would attempt a recharge, blown compressors pretty much make the unit a worthless brick. The Mach 10 is the direct replacement unit for the Mach 8, and the repair shop was able to locate one within driving distance.

So I paid about $1400 for the new unit, and with labor and materials the total replacement came out to about $2150. But, it was replaced at my site in about a 5 hour period from the time the tech arrived until they left at the end of the day. The configuration of the Mach 10 looks way different from the Mach 8, and so far the unit cools great, is a bit quieter than the 8 and draws an amp or 2 less when running.

Trying to cool the rig without a front AC was problematic, as the front end with all of the glazing is the hardest part to keep cool, and we had separate sun screens in the front windows to block the sun. I had briefly considered just swapping the middle and front AC units if we couldn't find a replacement. But if another AC failure occurred, that would leave one AC in the Phoenix heat and the RV would be unlivable. The swap still would have cost me over $500 in labor, so that option was seriously taken.

I did save the squirrel cage from the failed AC since we still have two Mach 8 units remaining. If I can just avoid running into "Murphy" for awhile.
 

Non-partic

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Jul 27, 2015
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136
Wow... nightmare. ...But you got your AC working right?

Since you are staying in very hot weather, here's an upgrade you might want to look into: I added a 8,000 BTU portable AC to my front cabin and hid in a cabinet. Then I cut a hole in my side wall to vent; and I tapped into my ATS using an extension cord. To read more about it you can visit these threads:



 

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UTTransplant

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Those squirrel fans do have a tendency to break up quite catastrophically, don’t they? We carry a spare just because of all the breakages we have heard about. Glad you found an AC to replace yours with; those things are in short supply!
 

SargeW

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Yes, I now have 3 working AC units again. On most RV AC units, once the Freon leaks out it cannot be replaced (easily) so replacement is the usual fix.

And you are correct, the squirrel cage disintegrated into a pile of plastic sticks, with only the end of the original cage still on the motor shaft. That underscored to probability of one or more pin holes in the coolant tubes.
 

John From Detroit

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Apr 12, 2005
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Davison Michigan
True squirlly story (Well squirrel fan)
Neighbor at the CG I stayed at in GA had a Carrier that was getting LOUD (Clatter type loud)
I helped him pull the cover over the squirrel fan and sure enough it was cracked clear to the hub.
Late Friday. hotter than.. The place you don't want to go (Gee it's 86 where I am only 84 in Hell, Mi.) and no chance of finding a new fan till Monday..... I returned to my rig.. Grabbed the one I'd salvaged when my first Carrier failed. and he was back in business...
 
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