Roof Air Delema...

MeRob

Member
I'm roasting !!! My roof air A/C suddenly quit... (Coleman MACH 14 HEAT PUMP)
The compressor ran for about 30 seconds then quit. The fan initially would run at low speed...but not high speed. Now the fan will only run at a very low speed then quit.
The fan shaft is free and fan spins easily by hand. No fan blockages visible. Breaker power is still on. :idunno:

Possible thermostat / controller fault ? Any suggestions ? Thanks, Rob
 

Old Crows

Calypso 2014 View Profile
Sorry Rob.... I haven't a clue. Is the shore power up to snuff???? Could be a 'brown out' and the supplied power is not up to snuff. Fuses and breakers OK?
 

MeRob

Member
That was quick! Thanks for the reply!
Everything that I can think of checks out OK. It was working well for the couple of hot days of our trip... then after 4-weeks of thunderstorms ...it got warm again and presto... the damn high speed fan made a sputtering sound and quit. Then the low speed sputtered then quit.
Had a good 30 amp service. No blown A/C breaker (unless the fan is on a separate circuit?) Fan shaft is free and spins easily by hand. Clean as new with no obstructions visible under the A/C roof shroud visible. Filter is clean. (15,000 miles on rig) duh? Tried spinning and starting it (blown starting condenser)... still no work. Weird ....Rob
 

MeRob

Member
Forgot to mention that the compressor starts... so could there be separate fuses associated with the fan motor? Hmmm
 

Old Crows

Calypso 2014 View Profile
Rob. What make, model and year is your RV? Also, is that an Airexcel/Coleman Mach 8 15000 Btu A/C - Heatpump?

There's two motors and fans. A squirrel cage for the air circulation and a vertically mounted motor with a fan on top. One or both not working???

You mentioned t-storms. Thinking lightning, here. Are you using a surge guard on the shore power?
 
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MeRob

Member
It's a 2012 Fleetwood 24 ft TIGA Sprinter. Yes, it's a Airecel Mach 15 Heat pump A/C The Squirrel cage was a little tight at first...but now hand spins free., I could not see a vertical fan on top. No signs of a lightning hit or power surge. Maybe a 'thermostat' problem? Compressor tries to run...but cuts out after 30 seconds. NO appreciable fan power. (The rig has a rear B/R slide so no roof ladder. Getting on the roof is a challenge! especially in a RV Park Ha! Thanks! Rob
 

MeRob

Member
My A/C is up and running again... I checked everything I could before venturing up onto my white 'toasty' roof in 90 deg weather... Eventually I had no choice. My Hard Start Capacitor was well below specs and my Fan Motor was dead. After replacing both, everything works great!

Note: On a single shaft-2-fan system (i.e. Coleman-Mach)... before replacing a Fan Motor, I suggest you MEASURE the amount of Shaft space NECESSARY between the Motor and the Radiator Fan! Evidently even the correct Fan Motors can come with a longer than necessary Rad Fan shaft. (trim the Fan shaft if necessary). The Squirrel Cage Fan shaft length is fine. There is very limited manuevring space in which to remove and instal a new Fan Motor without damaging the Rad Fins. A proper Rad Blade shaft length makes this job far easier! I tried it both ways! Rob
 

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