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Author Topic: Roof air conditioning woes  (Read 386 times)

dpickard

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Roof air conditioning woes
« on: October 27, 2017, 01:55:46 PM »
On a recent trip to Myrtle beach, the front rooftop air conditioner stopped working. The fan would come on and run fine, but no cooling whatsoever.
We stayed at Ocean Lakes. They have an RV service on site. Asked them to come and take a look.

Their "most experienced tech" was sent over. He climbs up and removes the shroud. He soon replaces the shroud and says "your capacitor looks fine. You aren't drawing any amps and I don't know how to work on a "shed system."  He leaves.

We called other service people who naturally were booked up and couldn't come.  We were told by one of them that we couldn't possibly have a shed system (whatever that is) because those work on 30 amps and were not installed on coaches that have 50 amp service.  Can anyone tell me if this is true and explain the shed system?
I feel this info may be useful to other folks on here.

Having had a recent experience at home with a Central air system that needed capacitor replacement, the serviceman said "you can't always just LOOK at a capacitor and rely on them to be bulged out on the sides when they fail." You should test. The Ocean Lakes guy didn't do any kind of test except for saying we weren't drawing any amps.

I don't know what to believe. The capacitor on the home unit was indeed bad and was replaced. It was perfect in appearance, but had failed.
I am wondering if I have the same situation with the rooftop air.

Also, another problem cropped up on this trip. This time it was the rear unit.  In the middle of the night (of course, when else???) we were awakened by the sound of water dripping steadily. Lo and behold, there was water coming through one of the ceiling lights dripping onto the bedroom carpeting. Thinking the unit had frozen up from prolonged running that day, we immediately cut it off to let it thaw.  After several hours we tried the rear unit again and about 8 hours later, same problem.

Not knowing how to check to see if the drain on the roof unit was stopped up and aggravated by the days events, we cut the trip short and headed home at daybreak.

Can anyone tell me how and where to check to clear the drain?

This MH had a capacitor go bad on the rear unit shortly after purchase on the way home from Key West during our maiden voyage with it.

When we first bought it, on the trip home from the dealer it stated raining water on me in the passenger seat up front whenever we applied the brakes and the dealer said it was a clogged AC drain and cleaned it out.

Our unit has 2 zones and a wall thermostat control. The thermostat says "RV comfort ZC"
The AC units themselves are Model number 9024-879 from "RV Products A division of Airxcel, Inc."

So:
1. Can anyone shed any light on what may be happening? or have any ideas?
2. Can someone instruct me on how to check and clear the drains?

Thank you in advance.

Dianne





Gil and Dianne
Piedmont area NC
2007 Allegro Bus 40 QDP

WILDEBILL308

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Re: Roof air conditioning woes
« Reply #1 on: October 27, 2017, 02:08:18 PM »
On a recent trip to Myrtle beach, the front rooftop air conditioner stopped working. The fan would come on and run fine, but no cooling whatsoever.
We stayed at Ocean Lakes. They have an RV service on site. Asked them to come and take a look.

Their "most experienced tech" was sent over. He climbs up and removes the shroud. He soon replaces the shroud and says "your capacitor looks fine. You aren't drawing any amps and I don't know how to work on a "shed system."  He leaves.

We called other service people who naturally were booked up and couldn't come.  We were told by one of them that we couldn't possibly have a shed system (whatever that is) because those work on 30 amps and were not installed on coaches that have 50 amp service.  Can anyone tell me if this is true and explain the shed system?
I feel this info may be useful to other folks on here.

Having had a recent experience at home with a Central air system that needed capacitor replacement, the serviceman said "you can't always just LOOK at a capacitor and rely on them to be bulged out on the sides when they fail." You should test. The Ocean Lakes guy didn't do any kind of test except for saying we weren't drawing any amps.

I don't know what to believe. The capacitor on the home unit was indeed bad and was replaced. It was perfect in appearance, but had failed.
I am wondering if I have the same situation with the rooftop air.

Also, another problem cropped up on this trip. This time it was the rear unit.  In the middle of the night (of course, when else???) we were awakened by the sound of water dripping steadily. Lo and behold, there was water coming through one of the ceiling lights dripping onto the bedroom carpeting. Thinking the unit had frozen up from prolonged running that day, we immediately cut it off to let it thaw.  After several hours we tried the rear unit again and about 8 hours later, same problem.

Not knowing how to check to see if the drain on the roof unit was stopped up and aggravated by the days events, we cut the trip short and headed home at daybreak.

Can anyone tell me how and where to check to clear the drain?

This MH had a capacitor go bad on the rear unit shortly after purchase on the way home from Key West during our maiden voyage with it.

When we first bought it, on the trip home from the dealer it stated raining water on me in the passenger seat up front whenever we applied the brakes and the dealer said it was a clogged AC drain and cleaned it out.

Our unit has 2 zones and a wall thermostat control. The thermostat says "RV comfort ZC"
The AC units themselves are Model number 9024-879 from "RV Products A division of Airxcel, Inc."

So:
1. Can anyone shed any light on what may be happening? or have any ideas?
2. Can someone instruct me on how to check and clear the drains?

Thank you in advance.

Dianne
The first thing I would try is turn the thermostat to off, pull the front of it off. there should be a fuse on the board. Remove the fuse (check the fuse to make shure it is good)
now re install the fuse and the front of the thermostat and try the AC.
Did this fix the problem?
Bill
2003 Bounder 38N
300 HP 5.9 Cummins
Allison 3000MH Trans.
Towing 2014 Honda CRV
Home base Fort Worth, Texas
A man who carries a cat by the tail learns something he can learn in no other way.
-Mark Twain-

dpickard

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Re: Roof air conditioning woes
« Reply #2 on: October 27, 2017, 02:48:52 PM »
The first thing I would try is turn the thermostat to off, pull the front of it off. there should be a fuse on the board. Remove the fuse (check the fuse to make shure it is good)
now re install the fuse and the front of the thermostat and try the AC.
Did this fix the problem?
Bill

Hi Bill...
Thanks for the suggestion!
I did as instructed, but the problem is still present.
I am attaching a photo of the thermostat so maybe you can see if it looks like the fuse is bad, because I am not sure if it is or not. I didn't see any filaments broken when I removed and replaced it.
The rear air still cools just fine; so I started thinking...if the fuse was bad, would the rear air unit cool as expected? I can only assume the fuse is ok.
Gil and Dianne
Piedmont area NC
2007 Allegro Bus 40 QDP

HueyPilotVN

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Re: Roof air conditioning woes
« Reply #3 on: October 27, 2017, 03:05:38 PM »
I will try to help, however I am sure that Gary or Lou will give you a more complete answer.

I do have a "Shed" or Energy management system in my 50 Amp coach.  It manages the use of the available electrical power by shutting down some circuits if there is not enough power available.  My system works on either 30 or 50 amp service and there is an indicator led to show which I am connected to and a digital display to show the actual amount of amps.

I will go out and take a picture of the display and post it in a few minutes.

The leaking water issue might be caused by loose bolts on the underside of the A/C units and might be corrected by tightening them to seal the gasket.  Mine did this before.

Edit:  The picture shows the display panel.  The flash from the camera caused the LEDs to not show very well but my current hookup is  50 amps.  Interesting to see that the front A/C is one of the circuits that can be shed if needed.

It also looks like it can shut down the compressor and leave the fan running on either A/C.

You might check and see if the A/C will operate by using your generator in case low power from shore power is the problem.
« Last Edit: October 27, 2017, 04:12:46 PM by HueyPilotVN »
Bill Waugh
40' Country Coach DP
34' Stacker Trailer, Trailer Toad
Jeep Commander
Mustang Bracket Race Car
35 years on the road

WILDEBILL308

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Re: Roof air conditioning woes
« Reply #4 on: October 27, 2017, 04:11:33 PM »
I think the fuse is good. Pulling the fuse for a couple minuets will fix a lot of oddball problems. Next, I see the thermostat is set on Zone 1, auto. Make shure zone 2 is set the same.
Having load sheading capability's is irrelevant if on 50 amp shore power. It should have no bearing on this problem. I think the teck was making excuses because he didn't know.
I would check your power/circuit breaker panel and check the circuit breaker for that AC.
With out a meter it is hard to trouble shoot the start capacitor but that would be my next step. That and looking at all the wiring connectors to the compressor. You might just try getting a "hard start" capacitor and swapping them out. Be carful as the capacitors hold a charge even when power is off.
Bill
« Last Edit: October 27, 2017, 04:13:41 PM by WILDEBILL308 »
2003 Bounder 38N
300 HP 5.9 Cummins
Allison 3000MH Trans.
Towing 2014 Honda CRV
Home base Fort Worth, Texas
A man who carries a cat by the tail learns something he can learn in no other way.
-Mark Twain-

dpickard

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Re: Roof air conditioning woes
« Reply #5 on: October 27, 2017, 04:15:38 PM »
I think the fuse is good. Pulling the fuse for a couple minuets will fix a lot of oddball problems. Next, I see the thermostat is set on Zone 1, auto. Make shure zone 2 is set the same.
Having load sheading capability's is irrelevant if on 50 amp shore power. It should have no bearing on this problem. I think the teck was making excuses because he didn't know.
I would check your power/circuit breaker panel and check the circuit breaker for that AC.
With out a meter it is hard to trouble shoot the start capacitor but that would be my next step. That and looking at all the wiring connectors to the compressor. You might just try getting a "hard start" capacitor and swapping them out. Be carful as the capacitors hold a charge even when power is off.
Bill

I have checked circuit breakers at the panel. None were off but I flipped them anyway.
Gil and Dianne
Piedmont area NC
2007 Allegro Bus 40 QDP

dpickard

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Re: Roof air conditioning woes
« Reply #6 on: October 27, 2017, 04:18:16 PM »
I will try to help, however I am sure that Gary or Lou will give you a more complete answer.

I do have a "Shed" or Energy management system in my 50 Amp coach.  It manages the use of the available electrical power by shutting down some circuits if there is not enough power available.  My system works on either 30 or 50 amp service and there is an indicator led to show which I am connected to and a digital display to show the actual amount of amps.

I will go out and take a picture of the display and post it in a few minutes.

The leaking water issue might be caused by loose bolts on the underside of the A/C units and might be corrected by tightening them to seal the gasket.  Mine did this before.

Edit:  The picture shows the display panel.  The flash from the camera caused the LEDs to not show very well but my current hookup is  50 amps.  Interesting to see that the front A/C is one of the circuits that can be shed if needed.

It also looks like it can shut down the compressor and leave the fan running on either A/C.

You might check and see if the A/C will operate by using your generator in case low power from shore power is the problem.

Hey HueyPilot...
I have tried using the generator. No success.
That is an interesting panel you have there!  Mine has nothing like that. Would it be safe to assume I do not have a shed system?
Gil and Dianne
Piedmont area NC
2007 Allegro Bus 40 QDP

HueyPilotVN

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Re: Roof air conditioning woes
« Reply #7 on: October 27, 2017, 04:22:05 PM »
If the EMS is shedding the front A/C compressor the circuit breakers would still be in the on position.  The real test would be to see if you are getting 120 volts to the compressor.

You can be hooked up to a 50 amp connection and still have a low voltage condition.  You might verify the voltage at the source and as mentioned before substitute the generator for shore power.
Bill Waugh
40' Country Coach DP
34' Stacker Trailer, Trailer Toad
Jeep Commander
Mustang Bracket Race Car
35 years on the road

HueyPilotVN

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Re: Roof air conditioning woes
« Reply #8 on: October 27, 2017, 04:27:04 PM »
I would think that you would have some kind of EMS panel if you had the system.

I am just an old country boy.  Hopefully an expert like Lou or Gary will see this and jump in with ideas.
Bill Waugh
40' Country Coach DP
34' Stacker Trailer, Trailer Toad
Jeep Commander
Mustang Bracket Race Car
35 years on the road

John From Detroit

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Re: Roof air conditioning woes
« Reply #9 on: October 27, 2017, 05:30:46 PM »
The amount of ignorance among service folks is amazing.. SHort story follows.

50 amp RV's often have SHED systems.. for use when plugged into 30 amps

On a SHED system the compressor is  cut off Far as I know blower two. if on 30 amps and drawing too much power elsewhere.

The tech should have tested for 120 volt to unit (present since the blower blows) and the control power to from the T-Stat.. Not sure myself how shed systems work (Cut off T-Stat or cut off 120vac) but it would only take me like 5 minutes tops to figure it out hands on, ,Why a pro can't do it I have no idea.


Short story: Looking for a key operated switch I went to 3 stores today. #2 was an Electrical supply.
Electrician there is installing a 30 amp RV outlet.. HE did not know if it was 120 or 240 volt.. He does now.   And without having to pay for it. He also did not know what to buy outlet wise

TT (Travel Trailer)- 30  of course.
Nothing adds excitement like something that is none of your business
My Home is where I park it.

bross

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Re: Roof air conditioning woes
« Reply #10 on: October 27, 2017, 05:55:28 PM »
If you do have a shed system I doubt that it is causing the problem because you said the fan runs on the unit but it doesn't cool. When my power management system sheds one of the ac units it shuts down completely, fan and all. There are numerous things that can cause the compressor to not start including things like low refrigerant pressures, faulty circuit boards or bad capacitors. I think you should find a good refrigeration company in your area and have them diagnose it. As for the drains on the other unit you can probably clean those out yourself. They are in the pan under the units on the roof. To get to them you will need to remove the cover and look for the holes that drain the pan. Sometimes they drain directly onto the roof or they may be piped to the ground. Look for leaves or other debris clogging the holes. If they're plugged, condensate will build up in the pan until it overflows into the air duct. You can usually clear them with a piece of wire.
Bill & Doris
Winnebago Adventurer 38Q

NY_Dutch

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Re: Roof air conditioning woes
« Reply #11 on: October 27, 2017, 06:10:36 PM »
You could try swapping the compressor start capacitors between the two units to see if the problem moves too.
Dutch
2001 GBM Landau 34' Class A
F53 Chassis, Triton V10, TST TPMS
2011 Toyota RAV4 4WD/Remco pump
ReadyBrute Elite tow bar/Blue Ox base plate

WILDEBILL308

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Re: Roof air conditioning woes
« Reply #12 on: October 27, 2017, 06:48:43 PM »
Make shure your filters ate clean. If the filters are dirty you get a vacuum and it won't let the water drain out because it is puling air in through the drain holes. Most likely it is the roof drains clogged.
Bill
2003 Bounder 38N
300 HP 5.9 Cummins
Allison 3000MH Trans.
Towing 2014 Honda CRV
Home base Fort Worth, Texas
A man who carries a cat by the tail learns something he can learn in no other way.
-Mark Twain-

dpickard

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Re: Roof air conditioning woes
« Reply #13 on: October 27, 2017, 07:05:32 PM »
Make shure your filters ate clean. If the filters are dirty you get a vacuum and it won't let the water drain out because it is puling air in through the drain holes. Most likely it is the roof drains clogged.
Bill

I thought about the filter thing, too.
I have several sets and always swap them out at the start of every trip and wash the ones taken down so they will be fresh for the next time.
GMTA!
Gil and Dianne
Piedmont area NC
2007 Allegro Bus 40 QDP

dpickard

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  • Posts: 237
Re: Roof air conditioning woes
« Reply #14 on: October 28, 2017, 09:58:23 AM »
If you do have a shed system I doubt that it is causing the problem because you said the fan runs on the unit but it doesn't cool. When my power management system sheds one of the ac units it shuts down completely, fan and all. There are numerous things that can cause the compressor to not start including things like low refrigerant pressures, faulty circuit boards or bad capacitors. I think you should find a good refrigeration company in your area and have them diagnose it. As for the drains on the other unit you can probably clean those out yourself. They are in the pan under the units on the roof. To get to them you will need to remove the cover and look for the holes that drain the pan. Sometimes they drain directly onto the roof or they may be piped to the ground. Look for leaves or other debris clogging the holes. If they're plugged, condensate will build up in the pan until it overflows into the air duct. You can usually clear them with a piece of wire.

Very useful info! We have numerous pin oak trees on our property and those pesky little leaves seem to penetrate places you wouldn't believe. Thank you.
Gil and Dianne
Piedmont area NC
2007 Allegro Bus 40 QDP

dpickard

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Re: Roof air conditioning woes
« Reply #15 on: October 28, 2017, 10:08:09 AM »
You could try swapping the compressor start capacitors between the two units to see if the problem moves too.

I would like to try to tackle this, but someone warned that the capacitors can still hold a charge even after unplugging the coach.

How do I get rid of that charge?  I obviously know nothing about such matters, LOL. I remember what a capacitor looks like vaguely because when the one on the rear went bad the serviceman held it up for me to see.

I am so tired of paying a "qualified service center" my hard earned money to screw up my coach worse than it was before. If anybody is gonna mess things up I can live with it if it is ME. 

I cringe when I remember the almost $3000 I spent trying to repair my generator when a $12.00 filter was the real problem all along. BTW that generator has performed FLAWLESSLY ever since!
« Last Edit: October 28, 2017, 10:12:10 AM by dpickard »
Gil and Dianne
Piedmont area NC
2007 Allegro Bus 40 QDP

John From Detroit

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Re: Roof air conditioning woes
« Reply #16 on: October 28, 2017, 10:34:02 AM »
If the compressor is not starting and drawing NO current.. Before I suspected the cap... I'd check for VOLTAGE. I suspect a relay in teh control box. OR the T-Stat.
Nothing adds excitement like something that is none of your business
My Home is where I park it.

WILDEBILL308

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Re: Roof air conditioning woes
« Reply #17 on: October 28, 2017, 10:56:52 AM »
No reason you can't learn the basics or even more advanced repairs. Try watching this video and there are several on the same subject.
https://www.youtube.com/watch?v=Ty_ou_TW5EM
Bill
2003 Bounder 38N
300 HP 5.9 Cummins
Allison 3000MH Trans.
Towing 2014 Honda CRV
Home base Fort Worth, Texas
A man who carries a cat by the tail learns something he can learn in no other way.
-Mark Twain-

Ernie n Tara

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Re: Roof air conditioning woes
« Reply #18 on: October 29, 2017, 09:24:03 AM »
You can discharge a cap by jumping across it or by shorting the ungrounded end (an end is grounded) to ground.

Ernie
Ernie 'n Tara

2011 Winn Journey 34y
2012 Jeep Rubicon - Dozer (orange - kinda)
2006 Jeep Wrangler

dpickard

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Re: Roof air conditioning woes
« Reply #19 on: October 29, 2017, 11:01:27 AM »
You can discharge a cap by jumping across it or by shorting the ungrounded end (an end is grounded) to ground.

Ernie

Thank you Ernie!
Gil and Dianne
Piedmont area NC
2007 Allegro Bus 40 QDP

 

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