Roof A/C dilemma

[minibike]

Last night, I was cruising this site looking for advice whether to repair or replacing a non-functioning A/C. Unfortunately, it'd been so long since I'd posted, I forgot my password and was unable to ask this question. After a few hours of internet reviews, I decided to take the plunge and this morning, ordered a new Coleman 15K A/C with heat strip at $1100+ installed (Ugh!). I take the RV in on Wednesday for the install. So I get home and start emptying out the fridge and taking out some personal items and on a whim I try to start the A/C once again. Lo and behold, it starts right up and cools wonderfully. I ran it for about 6 hours, stopping and starting it several times and it works just fine.

I plan on going ahead with the new A/C install, but I wonder what could have caused the 24 y/o A/C to just hum and not start before? I tried it on shore power at home, at the campground and on the generator with the same bad result. I hate to trash a now functioning A/C, so if I have it boxed up and put on a shelf in the garage, I'll have a backup for the rear A/C (or gift if I find someone in need).

My question to the group is do any of the A/C experts have any idea what kind of gremlin invaded this Coleman A/C? And what I should do to it to make sure it doesn't happen again?

[Mr_D]

Sometimes the motor bearings freeze up from non use. Maybe that was what happeneed and trying again jolted them loose?
That's one reason to run them every month in storage.

[minibike]

You may be right Mr D. I tried the A/C again today and all is well. We keep this RV on shore power and I run the A/Cs on a frequent basis, but maybe bumping along the highway did shake something back into place.

[biker art]

Originally Posted by minibike

You may be right Mr D. I tried the A/C again today and all is well. We keep this RV on shore power and I run the A/Cs on a frequent basis, but maybe bumping along the highway did shake something back into place.

I had an 88 jayco trailer I bought for $250 and it came with a roof AC that looked original but worked. I rebuilt the complete interior over a one year period,while using the AC during the summer months. After a while it started making noise and then stopped working. If I spun up the fan it would work until the next time. It was the motor bearings. Instead of trying to get a new motor I disassembled it and removed the bearings and made new ones in my little harbor freight lathe using oilite bronze. All fixed and running great. Try spraying some oil on the bearings. That maybe all it needs.

[minibike]

Thanks for the insight - I will file it away. Since I'd already ordered a new A/C, I followed through and replaced it. However, since it kept me cool all the way to the repair shop, I had them place it on a pallet and brought it home with me. Now to just find space in my shop . . .

[TQ60]

If it was a hum of compressor running but no air movement then fan bearings likely cause or fan capacitor but given it self repaired bearings or something stuck in fan.

But if hum was with air flow but no cool it could be locked up compressor that a bump may have patched.

Carefully handle old one so things do not change and open the cover and inspect it.

Turn the fan with your finger and if stiff then bearings.

If free then maybe capacitor.

If you only have a single unit on your rig and have space and wiring for second then use it.

Oil or replace the bearings and put a power cord on it so you can run it on the ground to test it then put it on as it is "free"

[vsheetz]

I had a mud dobber (aka wasp) build a nest that jammed the fan on a RV air conditioner. A visual inspection for something mind be a place to start.

[mel s]

Originally Posted by minibike

After a few hours of internet reviews, I decided to take the plunge and this morning, ordered a new Coleman 15K A/C with heat strip at $1100+ installed (Ugh!). I take the RV in on Wednesday for the install. So I get home and start emptying out the fridge and taking out some personal items and on a whim I try to start the A/C once again. Lo and behold, it starts right up and cools wonderfully. I ran it for about 6 hours, stopping and starting it several times and it works just fine.

I plan on going ahead with the new A/C install, but I wonder what could have caused the 24 y/o A/C to just hum and not start before? I tried it on shore power at home, at the campground and on the generator with the same bad result. I hate to trash a now functioning A/C, so if I have it boxed up and put on a shelf in the garage, I'll have a backup for the rear A/C (or gift if I find someone in need).

My question to the group is do any of the A/C experts have any idea what kind of gremlin invaded this Coleman A/C? And what I should do to it to make sure it doesn't happen again?

minibike
I have no idea why your A/C now works but I will offer this advice:

If it ain't broke don't fix it.

(From my own personal experience with my now 20 year old coach I can tell you that once you start replacing things that work you may not have enough $$ left to replace all the things that will NEED to be replaced).

Mel
'96 Safari (148k miles).

[F76Marion]

Minibike,

Have them take it off carefully and keep all the pieces. It should go for a couple hundred (at least one) on Craig's list.

Tell them you changed it to get the heat strip. You won't regret getting that.

Frank

[marjoa]

What is a heat strip and how does it work.

[Waiter21]

The heat strip is a heating element option available on most rooftop AC units.

HOWEVER - On some units (like mine) the heat strip is NOT controlled by any thermostat. When you select HEAT, it turns the element on and there is no temperature control. , it stays on until you turn it off.

[guardrail53]

Originally Posted by Waiter21

The heat strip is a heating element option available on most rooftop AC units.

HOWEVER - On some units (like mine) the heat strip is NOT controlled by any thermostat. When you select HEAT, it turns the element on and there is no temperature control. , it stays on until you turn it off.

Not the case in my Monaco, the heat strip is right on the choices on my thermostat, and is adjustable on both front and rear A/C's. Work's great to take the chill off on the cool mornings! They do very well down to about 40*, then you need to switch to the furnace! Rail!

[minibike]

Well, what's done is done. I do have some regret about replacing a "once again" functioning A/C unit, but we live in Florida and A/C is not optional. The rear unit cooled the RV effectively, but located inside the bedroom, it was noisy at night. We also use the generator and roof air while travelling and the rear air just didn't quite make it up to the front seats.

The new Coleman 15K unit is LOUD. Much louder that the older one was. I don't like that. The interior panel is also smaller than the older panel. Since the previous owner had the entire ceiling upholstered, there is a visible gap now (Coleman does not make trim piece - which I would think they would since surely I am not the only person to replace an A/C with a newer model). The louvers on the new unit do not adjust for air flow. You can open or close a vent, but you cannot adjust the direction of the airflow. I haven't tested the heat strip yet, but I expect it to perform as advertised. I guess I'll make the best of it, but it sure would be nice to have that $1100 back in my pocket. I'll cross my fingers and hope nothing else goes wrong. But I give credit to the previous owners of this rig. During their ownership, they maintained this rig meticulously and replaced anything that needed replacing with quality stuff. I guess I feel like it's my responsibility to continue that attitude.

And yes, the old A/C is riding around in the back of my P'up. As soon as I find room in my overcrowded garage to store that thing, I will.

[mel s]

Originally Posted by marjoa

What is a heat strip and how does it work.

marjoa
A heat strip is a $5O-$60 heating element option available on most rooftop AC units.
Heat strips work the same as, (and provide the same amount of heat as), any $20 1500 watt electric space heater.