AC Unit Quit Working!

We own a 2006 TM3023 and just returned from a 10 day trip. On the 2nd to last night, the AC quit working. The fan works but when turned on, the compressor trys to start but only for 2-3 seconds and then quits. There's a faint odd smell so I suspect that the compressor is the problem.

My question is ...

Where should I take it for an evaluation?

I am unfamiliar with the RV sales / service businesses in the Port Charlotte / Punta Gorda area so don't know if I want to go that route. There's a Camping World in Ft. Myers that is probably the best option but ...

Will they know TrailManors - how to set them up and put them down, etc.?

For installation, how much weight can be put on a TrailManor roof? Can one stand on it? I would think not but have never had to consider it. And if not, how would an AC unit be replaced?

Can one replace just the compressor in an AC unit? Are there other electronic components in the AC unit that might have been damaged therefore making it better to replace the whole unit as opposed to repairing it?

Thanks in advance for any assistance / opinions!

Oh, I forgot to mention in the original post that the power in the campground had gone out while we were away and came back on before we returned. The trailer was obviously plugged in that whole time so I was wondering if there could have been a damaging power surge that could have caused this damage when the power was restored. Just FYI ... there were no other electrical issues as a result of this incident ... just the AC problem.

Thanks again for any help!

[rvcycleguy]

The TM A/C is common to many of the RV's on the road. It is not TM specific. I would not advise a technician to stand or work on the roof. Some here have accessed the roof by placing boards or sheet plywood on the roof to give a supporting surface to work from but this would be to remove or replace the A/C unit only. The unit will have to be removed from the topside. Once the TM is opened, it's the same as most conventional campers. Controls on the inside and service to components from the topside. The Camping World techs should be experienced with the A/C units and will most likely use a ladder.

I'm an HVAC service tech (and contractor but don't tell anyone). Voltage spikes can damage motors (your compressor is a motor), and capacitors. Your compressor uses a capacitor to help get it started. Often times the symptoms you describe end up being just a blown (open or shorted) capacitor. An average service tech can find that and repairs should be nominal.
If it's the compressor itself unit replacement is the best route.

Thanks, Rio Dan ... great information! I've previously replaced capacitors on pump motors and that's not to difficult. Is this capacitor something that I can replace myself? If so, where can it be accessed ... from the top or bottom of the unit? Is the capacitor something that can be purchased online? I assume that it can be tested for a short thru the use of a multimeter ... an ohm range for a good capacitor and it's bad if it tests outside of that range, correct?

Thanks again!

Originally Posted by Tybraker

Thanks, Rio Dan ... great information! I've previously replaced capacitors on pump motors and that's not to difficult. Is this capacitor something that I can replace myself? If so, where can it be accessed ... from the top or bottom of the unit? Is the capacitor something that can be purchased online? I assume that it can be tested for a short thru the use of a multimeter ... an ohm range for a good capacitor and it's bad if it tests outside of that range, correct?

Thanks again!

First let me qualify: I'm not a TM owner yet, hence my guest status. And it's been a while since I've had an RV rooftop AC unit open. I work on bigger stuff.

Safety first: Make sure power is disconnected to the AC before removing panels! Capacitors are like batteries and can hold a charge. Always discharge the capacitor by shorting the terminals before touching them. You may even see a small spark when discharging a capacitor. This is normal.

I'm not sure if the capacitor(s) are accessed from the top (removing the exterior cover) or the inside (removing the interior cover plate). It may vary by manufacturer as well. There may be two capacitors, one for the compressor and one for the fan/blower motor. Or there may be one dual capacitor. If so it would have three terminals as opposed to two for individual capacitors. They usually have push-on terminals. When you open the unit find the wiring diagram. It will be helpful in locating and identifying them.

Testing a capacitor with a volt/ohm meter can be tricky. Unless you have a capacitance meter you can't directly measure a capacitor’s value. Unless the capacitor is dead shorted a digital meter is mostly worthless. If you have an analog meter (sweeping needle type) you can see if the capacitor is "good or bad".

Discharge the capacitor by placing something metal across the terminals. Remove the wires and discharge the capacitor again. Set your meter to ohms and place the leads on the terminals. If the needle swings up from infinity and then back down the capacitor is working. It may still be out of range of it's intended value but it's working as a capacitor should. If the needle doesn't move try some different ohm scales on your meter. Be sure to discharge the capacitor between checks. If it still doesn't move it's bad/open. If the needle moves all the way to 0 ohms and stays there it's bad/shorted.

On dual capacitors one of the terminals is common and should be marked with a "C" or Com. When you test this type one meter lead will always be on the common terminal.

If you find a bad capacitor Google the part number printed on it and you should be able to find at least one or two suppliers.

If your capacitors test good you can always take them to a variety of electronic repair places and ask if a technician can measure their values to see if they match the values printed on the cases.

If the capacitors are good and the compressor still won't start check the tightness of all the electrical connections. When the compressor hums and then goes silent it's tripping a thermal switch inside the compressor on the motor windings. It takes a few minutes after the switch trips for the windings to cool down and reset. The more you trip it the longer it takes. So if you energize the compressor and nothing happens the windings are still too warm and the thermal switch hasn't closed yet.

If all is good and the compressor still won't start then the compressor motor has likely suffered some damage. There is one last thing you can try before condemning the unit. HVACR supply houses sell something called a start kit or hard start kit or boost kit that can be added to the unit to help the compressor start. They cost more than capacitors but way less than a new unit. Tell the counter guy what it's going on and if he’s good he can recommend the appropriate size start kit. Install it per included instructions. It's not a repair, it's a patch. But I've used start kits on verified damaged compressors that wouldn't start and several of these compressors are still running many years later.

Hope this helps.

[Bill]

Good advice from Rio Dan. In my opinion, before you start tearing into it, you should get a copy of the manual for your specific unit. It can be downloaded from the mfr web site, and it will have a parts view that shows you specifically where the capacitor is located and how to get to it. You may also be able to get it from bryantrv.com.

While you are there, you might want to check into the "hard start capacitor" that he mentions. There has been a lot of discussion on this forum, so a search will get you going in the right direction.

Bill

[Barb&Tim]

Originally Posted by Rio Dan

First let me qualify: I'm not a TM owner yet, hence my guest status. And it's been a while since I've had an RV rooftop AC unit open. I work on bigger stuff.

Safety first: Make sure power is disconnected to the AC before removing panels! Capacitors are like batteries and can hold a charge. Always discharge the capacitor by shorting the terminals before touching them. You may even see a small spark when discharging a capacitor. This is normal.

I'm not sure if the capacitor(s) are accessed from the top (removing the exterior cover) or the inside (removing the interior cover plate). It may vary by manufacturer as well. There may be two capacitors, one for the compressor and one for the fan/blower motor. Or there may be one dual capacitor. If so it would have three terminals as opposed to two for individual capacitors. They usually have push-on terminals. When you open the unit find the wiring diagram. It will be helpful in locating and identifying them.

Testing a capacitor with a volt/ohm meter can be tricky. Unless you have a capacitance meter you can't directly measure a capacitor’s value. Unless the capacitor is dead shorted a digital meter is mostly worthless. If you have an analog meter (sweeping needle type) you can see if the capacitor is "good or bad".

Discharge the capacitor by placing something metal across the terminals. Remove the wires and discharge the capacitor again. Set your meter to ohms and place the leads on the terminals. If the needle swings up from infinity and then back down the capacitor is working. It may still be out of range of it's intended value but it's working as a capacitor should. If the needle doesn't move try some different ohm scales on your meter. Be sure to discharge the capacitor between checks. If it still doesn't move it's bad/open. If the needle moves all the way to 0 ohms and stays there it's bad/shorted.

On dual capacitors one of the terminals is common and should be marked with a "C" or Com. When you test this type one meter lead will always be on the common terminal.

If you find a bad capacitor Google the part number printed on it and you should be able to find at least one or two suppliers.

If your capacitors test good you can always take them to a variety of electronic repair places and ask if a technician can measure their values to see if they match the values printed on the cases.

If the capacitors are good and the compressor still won't start check the tightness of all the electrical connections. When the compressor hums and then goes silent it's tripping a thermal switch inside the compressor on the motor windings. It takes a few minutes after the switch trips for the windings to cool down and reset. The more you trip it the longer it takes. So if you energize the compressor and nothing happens the windings are still too warm and the thermal switch hasn't closed yet.

If all is good and the compressor still won't start then the compressor motor has likely suffered some damage. There is one last thing you can try before condemning the unit. HVACR supply houses sell something called a start kit or hard start kit or boost kit that can be added to the unit to help the compressor start. They cost more than capacitors but way less than a new unit. Tell the counter guy what it's going on and if he’s good he can recommend the appropriate size start kit. Install it per included instructions. It's not a repair, it's a patch. But I've used start kits on verified damaged compressors that wouldn't start and several of these compressors are still running many years later.

Hope this helps.

Rio Dan, Very well written instructions! Welcome to the board

[ShrimpBurrito]

Originally Posted by Barb&Tim

Rio Dan, Very well written instructions! Welcome to the board

Agreed. This is library material! Welcome!!

Dave

Thanks to all ... excellent input!

Rio Dan - what can I say - above and beyond the call of duty - thanks so much!

Bill - excellent additional input. The trailer is "up" right now being cleaned from our trip so I'll get the manufacturer & model number of the whole unit when I can check under the top cover. I took off the inside cover and the numbers only pointed toward the ceiling unit (p/n 9330C715) and not the manufacturer or the "upper unit".

This has been excellent input ... thanks, all!