Electrical Burning Smell from AC Unit

[zboss]

Tonight we got an electric burning smell from the cooling vent of one of our AC units. Its still cooling but when we turn it off the smell goes away, turn it back on and the smell comes back. I suspect a failing motor or bearings since we checked the area where all the electrical wires are and it doesn't smell at all.

I'm not sure if its practical to repair the unit or just better off replacing it (assuming this is the issue).

- z

[Pitchondesign]

Need more information. How old is the unit? Is it really the fan motor? Are any other electrical components burned? Can you get parts? Are you comfortable opening up the unit and replacing parts? How hard is it to get to the fan motor and other parts? How long will it take to get parts? How long can you be without AC?

The list can go on, but you get the idea.

[chrisr]

any smoke ?

may be dust on a heating element somewhere ?

cheers,

[zboss]

We are running cooling so no dust is being burned off. This is definitely not a dust smell.

What I am asking is - do people really repair old units or just get new ones?

[chrisr]

Originally Posted by zboss

We are running cooling so no dust is being burned off. This is definitely not a dust smell.

What I am asking is - do people really repair old units or just get new ones?

we have 2 fairly elderly air con units so this is a question close to my thoughts. up to a point repairs are worthwhile...past this point it's time to replace.

but where is this point ? suggest it depends on the cost of repairs v the depth of the pocket x owners views on having everything perfect or 'just good enough'

i had a friend overhaul our compressor motor for a case of beer, but now we have other issues and so starting to think about replacement

one big plus for replacement is that new technology means new a/c will be much lighter and more efficient, but bottom line is you need to compare price to repair v price to replace

cheers,

[Stewie12]

I have found that by the time you pay callout charges to be told that the compressor is finished, I would have been better putting that money towards the cost of a new one.

[Cadence]

The efficiency of a newer unit should be considered. I might pay in the long run.

[Spot]

A start/run capacitor or a fan motor could be suspect and relatively easy to replace.
Beyond that it might be better to invest in the future A/C instead of the past.

[jharding]

some of those fan motors have a tube at the end to spray a lube into to lube the end bearing, you might feel the end of the fan motor and see if it is hot

[sailorboy1]

Originally Posted by zboss

What I am asking is - do people really repair old units or just get new ones?

I am sure it all depends on the WHAT is the problem. I doubt I would be considering replacing a $1000+ unit for the want of a $100 standard motor.

[Cadence]

Originally Posted by jharding

some of those fan motors have a tube at the end to spray a lube into to lube the end bearing, you might feel the end of the fan motor and see if it is hot

That's probably fans with oil lites in place of bearings. I guess it might be worth a try. If those bushings hadn't been oiled on a regular bases it is probably to late, if that is the case.

[Brewgyver]

Originally Posted by Spot

A start/run capacitor or a fan motor could be suspect and relatively easy to replace.
Beyond that it might be better to invest in the future A/C instead of the past.

+1 on this. In a self-contained, water-cooled AC unit, the most likely suspects for such smells are the blower motor and the capacitor. If the air volume seems normal, it's not likely to be the blower motor. Capacitors will sometimes fail slowly, and they will definitely produce odors.

In many cases, a dual capacitance cap is used, connected to both the compressor and blower motor. They're relatively cheap, and an excellent spare part to keep aboard.

[Mike Banks]

What Spot said.

[zboss]

I'm going to pop open the unit and take a look at the capacitor using a guide I found recently on the topic. Probably replace that if I can find a suitable replacement. Maybe also just replace the fan motor while I'm in there. It's a pain in the rear to move from its installed location.

I think the unit is maybe only 6 years old since it says "cruisair by dometic" but the new dometics just say "dometic" and the old ones from Cruisair just say "Cruisair". I have a technical service request out to dometic using the serial numbers on the unit.

[Brewgyver]

The capacitor should be labeled with it's voltage and capacitance. Don't be surprised if it's marked 370 volts, that's not a mistake. If it's a dual cap, it may list capacitance as 25/3, 30/5, etc. There are many possible ratings.

No need to buy the cap from Dometic, they don't make them anyway, and there's no such thing as a "marine" capacitor. Most HVAC parts houses tend not to sell to the general public/DIYer, so find the ratings and just order online from the Amonster