Roof Air Conditioner kills power - Repair or Replace?

[Old Man Powell]

Finally got our "new" RV home yesterday. I turned on the A/C and it seemed to be working great but then it would kill the power periodically. Long story short, think the comppressor is killing the power when it tries to come on. The RV is a 1974 and I have absolutely no idea if the A/C is original or not. I climbed on top earlier and I think it's an old "Duo-Therm." Can these old units be serviced or am I going to be shoping for a new unit? Any recommendations on brand and BTU? It's the 27ft chieftain. Unit sit not excatly in the middle, litte closer to the back sleeping area. Already budegted money for tires, brakes and carb... was not ready for this! Oh well!

[HandyDan]

How do you have it powered?  Generator, Shorepower, Adapter to housecurrent?  It could be it just needs to be cleaned out.  Take the shroud off and look inside.  You should, also, take a power phillips screwdriver and take out the multitude of screws holding on the metal cover.  I'm betting the condenser and/evaporator is covered with mud dubbers.  You should do this yearly as  just normal maintenance.  See if the motor turns freely. 
If you have it plugged into your house on a normal 15amp outlet, that isn't enough power and will pop a circuit breaker. 

[Old Man Powell]

I was wondering if it wasn't getting enough power. Previous owners (my sister and her husband) had it at a campsite for the last two years and never had any problems. I brought it home and plugged it into an outside plug using the typical adapter. Never tripped the breaker in my house but that isn't to say it still wasn't getting enough power. Per your suggestion I will definitely climb on top and take the cover off... give it a good cleaning. The air coming out was nice and cold.

I did run it with the generator running but not long enough to see if it would trip the breaker again. Generator has old oil in it so want to change oil before I run it for any length of time.

Thanks!

[Old Man Powell]

Guess I should clarify some more. The breaker in the RV never actually popped. The power to the RV would just completely "disappear." I would manually flip the breakers off and then back on. After a minute or so the power would suddenly come back. Very odd. Of course I am no electrician at all so take all of this with a grain of salt... and try no to laugh too hard! Could I be looking at a different problem that is just being brought to my attention via the A/C? Power is fine with just the fan on the A/C unit running. I just assumed it was from the compressor trying to come on.

[legomybago]

Sounds like a relay tripping?...not sure where in the system you would have one though  Hm?

[M & J]

Pictures. We think better with pictures....

[Lefty]

A regular household plug is only capable of supplying 15A of power usually. This is a total amount across every outlet on that circuit. You can plug your RV into a circuit like that to supply power for the lights and fridge... but not the roof air.

You really need a dedicated 30A outlet installed in a weatherproof outlet box near where you'll be parking it.

Depending on what the regulations are where you live, you may can install one yourself, or might have to get a licensed electrician to install one. If you have an empty slot in the outside breaker panel at your home, they are really simple to wire up.

If you run the RV with low amperage, you can damage the capacitors due to "brown out".

[legomybago]

you can damage the capacitors due to "brown out".

Yeah....Same thing has happened to me....Thanks Jim Beam W%

[Oz]

90% chance your problem is what Lefty said.  It happens all the time with new RVers.  Especially since it worked fine at the campground, which has a dedicated, 30 amp service.  I did the exact same thing myself.  After I put in a Carrier V, I could run the A/C on low and it wouldn't kill all the power, but not so with the older units.  The original Coleman would kick on, then just power down and hum. 

It just pulls too much for the house circuit to handle.

Here's some more good info to look at for servicing:
http://www.classicwinnebagos.com/forum/index.php/topic,7982.msg38026.html#msg38026

Also, if you can get the make and model, chances are we have the manual for it in the Member ARea.  If not, there's a very good, general A/C service manual there too!

[Old Man Powell]

Great stuff guys! Appreciate the info.

[Old Man Powell]

Was finally able to compress the picture down a bit. Not a great picture and Rooster is pretty dirty from sitting so long.

[legomybago]

What a beast!!

I'm a fan of the avatar too.

[DaveVA78Chieftain]

The breaker in the RV never actually popped. The power to the RV would just completely "disappear." I would manually flip the breakers off and then back on. After a minute or so the power would suddenly come back.

Now if we used auto resetting breakers on the AC side I might understand that however I have never seen that style breaker on the AC side.   Something does not sound correct.

Anyway, while you have it opened up, you also want to open the electrical box and look at the capacitors.  I had to replace mine due to age last year.  They were swelling up and about to burst.  Fan was OK but compressor unit did not want to start with them like that.

Dave

[PwrWgnWalt]

Wonder if someone has added a Surge Protector/Electric Management System into the power supply line somewhere?  (like a Progressive Industries, or Tech. Research Group/Surge Guard unit)

Am not uber experienced with these, but they advertise power protection on the LOW side, too... and the Progressive Industries EMS units have a time delay for A/C compressors...

Just a wild guess!  W%

- Walt

[Oz]

Good idea, Walt!  That's something not many would think of.  Definitely check.  Looking at the picture, I'm guessing the POs really didn't do much in the way of upgrades, but you never know.