Coleman mach AC Compressor Cutting on and Off

First of all, thanks for having me.
I actually found a ton of help here and it did help me replace my bower motor.
The
Problem started where the AC would be on ... (thermostat) Auto... Cool... Compressor cut on fine but fan would lock up after about 2 minutes,  hum pretty bad then kick my 20 amp breaker. 
Did some troubleshooting and found out after going up on top RV the fan was very hard to turn.
Fasco D1092 1/3 HP. Found replacement on Amazon for for $95.

Came today. All wires, screws etc matched and worked great.
Just as I thought I was the RV AC Guru..... Fan and Compressor ran fine for 6 mins (cold as normal). Then compressor decided to shut off but fan works great.  So I am thinking the fan was at least the problem at that time. 
I do hear the compressor kick on after about 10 mins or so but shuts off after about that 6 mins.

As of yesterday, compressor worked fine and fan was not.
I did some troubleshooting on making sure fan and fins clear and clean. Breaker does not trip.
Nothing has changed power wise since it was working.

Blower motor had 2 brown wires, one with white stripe that went to capacitor that matched great.

Even found a troubleshooting guide to the Thermostat and between 2 sets of wires I should have 12v. I do.

I however did not change capacitor and should have while I was up there but do capacitors cause compressors to go on and off and would it be just coincidence that it went bad right after my new motor went in?

Mentally exhausted trying to figure it out.
Any ideas or suggestions would be appreciated.
Chris

"I however did not change capacitor and should have while I was up there but do capacitors cause compressors to go on and off..........."

In a word, Chris .............. yes, they can.  But it would be an "indirect" effect.  A bad cap can cause the compressor windings to overheat and a protective sensor in the windings will shut the compressor down.......saving its life, so to speak.  Capacitors are pretty reasonable and you can always use a spare.

Howsomever ............. A/C problems can certainly come in "twos" but not real often.  SOooo re the fan/blower motor you replaced (for good reason):  is there a chance that the evaporator fan could have been re-installed backwards?  Or, is there a chance the fan is not at the same place (longitudinally) on the shaft?  In other words, is there a LOT of hot air blowing outward thru the evaporator up there on the roof?  If not, that too could cause high head pressure and compressor winding overheating........ then compressor shutdown via the overtemp sensor in the winding(s).

We have several guys here on the forum that are pretty savvy re A/C .  Hopefully they will chime in with their thoughts for ya.  My experience with RV A/Cs is very limited (many years in Res and Light Commercial)  ....... but there are many similarities; e.g., compressors is compressors. :^)

Good luck on the fix............... ed s 

From my understanding the dual run capacitors, for the fan it's a "start" capacitor for the compressor it's a "Run Capacitor " if compressor is having issues I would try the capacitor.

youracman said:

"I however did not change capacitor and should have while I was up there but do capacitors cause compressors to go on and off..........."

In a word, Chris .............. yes, they can.  But it would be an "indirect" effect.  A bad cap can cause the compressor windings to overheat and a protective sensor in the windings will shut the compressor down.......saving its life, so to speak.  Capacitors are pretty reasonable and you can always use a spare.

Howsomever ............. A/C problems can certainly come in "twos" but not real often.  SOooo re the fan/blower motor you replaced (for good reason):  is there a chance that the evaporator fan could have been re-installed backwards?  Or, is there a chance the fan is not at the same place (longitudinally) on the shaft?  In other words, is there a LOT of hot air blowing outward thru the evaporator up there on the roof?  If not, that too could cause high head pressure and compressor winding overheating........ then compressor shutdown via the overtemp sensor in the winding(s).

We have several guys here on the forum that are pretty savvy re A/C .  Hopefully they will chime in with their thoughts for ya.  My experience with RV A/Cs is very limited (many years in Res and Light Commercial)  ....... but there are many similarities; e.g., compressors is compressors. :^)

Good luck on the fix............... ed s

Click to expand...

Ed, thank you for your speedy response to my topic.
I measured the fan placement but I guess slightest change while tightening it up may be crucial.  I will check this tomorrow when troubleshooting.  I didnt take the fan out of the housing and slid it on the same way it came off due to being scared I would do something backwards. When you say outward, the fan should be pulling air and not pushing correct?
I have the old motor so I will measure the placement and check the direction.
It's funny you say the direction as a few reviews out of about 200, skimming through, I noticed a few complaints of motor spinning wrong direction. But I guess it would not be blowing inside as the little spinning wheel inside would be bacwards too.
Although I am very new at this.  First time I am trying to do things for myself being disable.

As for the capacitors, I should have ordered and just replaced them anyway but good to hear that they can cause the issue I am having but with the fan running well and compressor having a sudden issue, you have me questioning my skills!
I will for sure check that tomorrow.

I thought this all was going to be rough, had a quote of $400 to replace the motor, was told 2 to 3 hours, I did it in an hour with this forum and a video on youtube. 

PS. Thank you too Willandgiselarv, I will replace them good or bad. Cheap enough and good upkeep!

Are you sure you have constant voltage to the compressor terminal when in the auto cool mode? Try running it in manual cool mode before working on the unit itself. My Dometic airs only run the fan in medium speed it seems when in auto mode, and it could be cutting out on high pressure if it's really hot out. I usually run mine in manual cool and high fan for day time use and auto for evening and night use.

Time for me to fess up to another senior moment, Chris.  I mistakenly typed "evaporator" when I  meant "condenser" fan !!!!! 

You are right, of course ....... the blower wheel for the evaporator would not "pump" air into the conditioned space if it were turning backwards.  If the air flow inside is normal, the motor is turning the right direction.

Sorry for the mix-up.  Methinks I should not type after bedtime.  :^)

Charlie made an interesting post re his Dometic.  Good info to have.

Hopefully a new capacitor will make things right.  Capacitor change-out sure fixes a lot of RV A/C's. that's for sure.

Best of luck on the fix..............and safe travels.  ed s

youracman said:

Time for me to fess up to another senior moment, Chris.  I mistakenly typed "evaporator" when I  meant "condenser" fan !!!!! 

You are right, of course ....... the blower wheel for the evaporator would not "pump" air into the conditioned space if it were turning backwards.  If the air flow inside is normal, the motor is turning the right direction.

Sorry for the mix-up.  Methinks I should not type after bedtime.  :^)

Charlie made an interesting post re his Dometic.  Good info to have.

Hopefully a new capacitor will make things right.  Capacitor change-out sure fixes a lot of RV A/C's. that's for sure.

Best of luck on the fix..............and safe travels.  ed s

Click to expand...

No worries!  I still need to make sure the fan up top didnt slide up or down the shaft (longitudinally) as I do question myself on that now. I wasnt able to get up there today but will tomorrow or Tuesday and will replace that capacitor when I am up there.



Charlie, I tried manual AC today instead of Auto and the compressor still cycled on and off.

However, It seems like at night it doesnt cycle as often so something up there is probably heating up. Hopefully the capacitor. Or hopefully the fan thats at the condenser maybe is not longitudinally positioned perfectly.

I talk like I know what I am saying.  :-\