Dometic Penguin A/C fan problem

[CBWELL]

I am having a problem with my Dometic A/C unit. Couple of weeks ago it would not start, and only hummed. I replaced the start capacitor, cleaned all the finns andd the whole unit. Everything worked perfectly. Last week went on the road and first night I thought I would try the A/C. Only got a hum again. Next day after 5 hours on the road the A/C started perfectly. I shut it off and tried in about 15 minutes and only a hum. Got home yeterday and tried it again and worked perfect. I am thinking that the fan motor has a flat or bad spot on the armature, and this is causing the problem. I am wondering if the fan is turning when going down the road with the air entering the housing. Anybody had a similar problem, and or replaced the fan motor?

[Hans627]

Will the fan run independent of the compressor (in fan only mode)?

[CBWELL]

Fan will not start in any mode when turned on. In A/C mode, the fan starts and runs for approx 2 minutes before compressor starts.

[Wazbro]

IF that is the original A/C on your 94, yes it is due for the fan to seize. 8 or 9 years ago that happened to my brothers 86 and 5 years ago it happened to my 88. The matching fan for my brothers was $350 at the time and new A/C was $700, no sense spending half the cost of a new A/C for a 28 year old A/C so he replaced it. My A/C wasn't doing that well for cooling when the fan quit so I just replaced mine as well without checking fan price.

[CBWELL]

It's about 2K Canadian for a new A/C unit installed, so $350 for fan motor looks good!! I have a new control board installed a couple of years ago. If the compressor dies, I would replace the unit. Biggest problem right now is finding a unit, and then finding someone to replace it!! I really want to know if anyone has had the same problem, and if it was the fan motor that was causing the problem.Replacing the unit is relevant ONLY if parts are not available , or cost of parts exceded the cost of new unit. I replace the A/C Armstrong unit on my 1976 because I was told by a dealer that they could not be recharged. I found out later, that I was lied too and they could be repaired very easly and cheaply.

[Wazbro]

Originally Posted by CBWELL

It's about 2K Canadian for a new A/C unit installed, so $350 for fan motor looks good!! I have a new control board installed a couple of years ago. If the compressor dies, I would replace the unit. Biggest problem right now is finding a unit, and then finding someone to replace it!!

Well that was 8 or 9 years ago, before prices and availability went crazy. Also I believe he could find A/C fans for $150-200 back then that didn't fit his A/C.

[emelaich01]

When you serviced the unit, was the fan turning freely and did you try getting oiling the motor shaft(s)? If it spins freely for a dozen or so rotations, then yes, it's probably an electrical problem within the motor with one exception: there's always the possibility that you got a bad replacement capacitor.
If you have access to a VOM or multimeter, check between the 'com' and 'fan' terminals at the 1000 ohm setting. Prior to testing, use a screwdriver to short between the com and fan and com and hem (or comp) terminals. This removes any stored charge the cap may be holding.
You should get zero ohms initially with the resistance gradually rising or if you have a digital multimeter, the resistance displayed should gradually increase. If so, the cap is good and it's probably the motor but if not, substitute a known good capacitor and see if the fan motor now operates.
Good luck!

[CBWELL]

Thankk you for the comments, emalaich01. When I replaced the capacitor I also blew out the coils and the exposed fan blades, which turned quite freely. I didn't oil the ends of the shafts as I live on a gravel road that is 5 miles to pavement and the dust is horrible. Afraid of getting dirt into the bearings or bushings. It's raining right now but will remove the cover tomorrow and do the tests you suggested. It seems funny that the fan motor has an intermittent problem, and acts just like the brushes are going, similar to power tools. Thanks again for your help, Chris.

[uncle_bob]

Hi

Given the supply chain issues and the passage of time, finding any unique parts for an older appliance is getting harder and harder. What might have been easy to find for $350 five years ago might well be impossible to find these days.

Bob

[JCWDCW]

I would be looking for a bad connection
Check the wrong where you made cahsnges or maybe moved a wiring harness

[crazylev]

Just a thought: We had an issue at a state park. I turned on AC, just to fan, and I got the humming you mentioned. Long story short, check the voltage coming out of where ever you are. This was our problem. Unstable/dropping voltage at pedestal. I unplugged everything from the post. Older wiring at some parks can't keep up with the demand of modern camping gear.

[CBWELL]

Voltage has been stable at 116-120 volts at all locations. I have a digital voltmeter plugged into kitchen outlet at all times. When I installed the new capacitor, I checked all connections , including the run capacitor, and all were good. Connections on the inside all are good. Thank you for the idea's!

[davidz71]

I delt with this issue first day of a five day vacation at a State Park this past June. I took the ceiling assembly off from the inside, reached up inside to spin the squirrel cage. I then turned the fan on and was able to get the fan motor running before the Easy Start engaged the compressor. That lasted for 20 minutes then the fan motor quit. I couldn't get it to run again. I called my local RV place and the guy said he had tracked down 3 Penguin fan motors the year before, all in CA. and he bought one. When he got into the Domestic he said the motor was shot. At that point we both agreed to replace that Dometic Penguin 13.5k with a new 15k Dometic Brisk Air II. It took a couple days to get it into the shop and half a day to install/test. That Brisk Air was much more quiet than the Penguin and kept the 25' Sovereign cooler during the day than the Penguin it replaced.

[Boxite]

AC fan motors have what appear to be non-accessible, permanently-lubricated bearings. After a half dozen years the bearings become dry and become rough and occasionally seize. They will work one time..but not the next time.;

The FIX…(for cheapskates) …is to remove the fan motor, remove the four long screws which hold the motor together, pull the armature out (it’s brushless so a simple thing)…and if you look at each end-plate of the motor you will see the bronze plain bearings actually sit in a sandwich of sintered bronze washers which you should SOAK in ordinary motor oil or 3-in-one oil… then reassemble the motor in reverse order. It takes aobut 20 or 30 minutes. It will then last another half-dozen years when you must do it again.

OR…. you can spend ridiculous money and replace the motor OR the entire AC unit. Your choice.

[CBWELL]

Well, problem has been solved!! I found the model number of the A/C unit, thanks to Airstream Inc, and the replacement part number thanks to a wonderful person at Dometic Inc!! Part has been ordered from Dyers RV, for less than $225. I'm not a cheapskate, but FRUGAL!! Too many times I have been told to replace things when they can be easily repaired. Figure that it cost about 10% of a new A/C to repair the old one. Thank you for all of the help. Chris

[kaylorsan]

I had similar problems. I installed a soft start and changed the motor before determining that it was the start capacitor.

I learned a lot in the process and always a ‘enjoy’ a good problem to solve. This one cost me a little extra time and money tho.

My thread on the issue is titled ‘Dometic AC Unit drawing excessive power on startup’.

[CBWELL]

Final update! I installed a new Run/Start capacitor as well, and the A/C works like new. Total cost about 10% of a new unit installed!! Well worth it to me.

[kaylorsan]

Excellent! Glad to hear that you are up and running again.

[TeddyK]

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