Coleman Mach Basement Air Issue

[Armydave]

Hello,

I have searched all the previous posts and have not found anyone with my particular issue. My air cycles and works as it should when connected to shore power. But when on the generator (5500) it will only run compressor #1. Tries to cycle on #2 but no success. I have replaced the fan motor and all capacitors. Checked breakers on the gen set also. Just cant figure this out. Any help would be appreciated. Thanks.

2004 Itasca Suncruiser Set-up for 30 Amp Service on shore power.
Dave

[Neverenuff]

odd that is runs normally on 30A shore power. If I am doing the math correctly to convert Watts to amps (watts / volts = amps & amps x volts = watts), then your genset has a 45 amp output potential. That may be a surge rating but still your genset is capable of meeting / exceeding the output potential of a 30A shore power connection. So, say both shore power and genset are providing 120V single phase power, why does it work on shore power? Makes me suspect a power supply problem instead of an issue with the AC unit. What if the genset is not producing rated power for one reason or another? Maybe it runs under speed or fluctuates speed? Maybe some coil excitation issue? Or what is there is a power drop between the genset and the power circuit for the ac unit. Maybe a connection in the ATS or some other issue with the ATS? I woulld at least try to ensure that the genset is getting its rated potential to the ATS and over to the 120V bus that powers that AC unit. Good luck. You'll solve it and I hope you let us know what you find.

[al1florida]

Originally Posted by Armydave

Hello,

I have searched all the previous posts and have not found anyone with my particular issue. My air cycles and works as it should when connected to shore power. But when on the generator (5500) it will only run compressor #1. Tries to cycle on #2 but no success. I have replaced the fan motor and all capacitors. Checked breakers on the gen set also. Just cant figure this out. Any help would be appreciated. Thanks.

2004 Itasca Suncruiser Set-up for 30 Amp Service on shore power.
Dave

Have you monitored the 120V AC voltage when on shore power & generator to see if there is significant drop in voltage as compressor #2 starts when on generator? Also compare it to when on generator.
Also does your rig have the power control center which shows the shore power/generator power amps? If so what amps is compressor #2 pulling when it starts? Both shore & gen power.

[Armydave]

Thanks guys. I do have the EMS system. It pulls around 20amps now on shore power with both compressors running. It used to pull a few more before I replaced the fan motor but my tech said that is normal because the fan is operating smoother. Had it in the shop and the tech measured the output of the genset and said it was normal. Not sure if he actually checked it at the #2 compressor specifically. When on generator #1 kicks on normally and then cycles to #2. The amps spike to the upper 20's then it settles back down to around 13-14. From what I've read that tells me that #2 did not kick on. I took temp reading at the intake and output when on shore power with both pumps running and it was a difference of about 25 degrees. So normal from what Ive read. I can survive with only compressor #1 running on the generator because my dash air works well. But of course I would prefer to have it working properly and I want to insure that I am not doing any damage to the unit.

Thanks Again,

Dave

[hp1]

Take a look at your generator brushes, not an ohm test, a physical look, hope this helps.

[al1florida]

Originally Posted by Armydave

Thanks guys. I do have the EMS system. It pulls around 20amps now on shore power with both compressors running. It used to pull a few more before I replaced the fan motor but my tech said that is normal because the fan is operating smoother. Had it in the shop and the tech measured the output of the genset and said it was normal. Not sure if he actually checked it at the #2 compressor specifically. When on generator #1 kicks on normally and then cycles to #2. The amps spike to the upper 20's then it settles back down to around 13-14. From what I've read that tells me that #2 did not kick on. I took temp reading at the intake and output when on shore power with both pumps running and it was a difference of about 25 degrees. So normal from what Ive read. I can survive with only compressor #1 running on the generator because my dash air works well. But of course I would prefer to have it working properly and I want to insure that I am not doing any damage to the unit.

Thanks Again,

Dave

Pulling about 20-21 amps with both compressors running is what I see on our 2006 Journey.
Jumping to the upper 20's or even the low 30's is normal when compressor #2 starts. What do you see when on shore power? Does it jump into the 30's for any length of time? Say 4-6 seconds or just long enough for the EMS to briefly display the amps. Both shore & gen power.
Also it is important to know what the voltage is, when on shore & gen, when compressor #1 is running and when compressor #2 kicks on.
Checking the brushes is probably a good thing to try. How many hours on the generator? I have no idea how many hours the brushes should last. I would think well over 1000 hours of gen run time.
I think we are trying to determine if there is an EMS problem, a generator problem, or an air conditioner problem.
This is where it is helpful for current and voltage measurements be recorded for every running condition. Not just amps on compressor #2 starting when on generator.

[Armydave]

Thanks again. We are about to head out for a few days with it to escape the rain from this storm. I will do some research and get back with you. Generator has about 500 hrs. My generator has a 30 amp and a 20 am breaker. I recall reading something in the past about the 30 amp running compressor #1 and the 20 amp running compressor #2? Not sure if that is correct? just wondering if maybe replacing my 20 amp breaker may do anything? Grasping at straws here. But I will run the test on shore power and genset when we get set up. Thanks for all the info.

Dave

[BobC]

Originally Posted by Armydave

Thanks again. We are about to head out for a few days with it to escape the rain from this storm. I will do some research and get back with you. Generator has about 500 hrs. My generator has a 30 amp and a 20 am breaker. I recall reading something in the past about the 30 amp running compressor #1 and the 20 amp running compressor #2? Not sure if that is correct? just wondering if maybe replacing my 20 amp breaker may do anything? Grasping at straws here. But I will run the test on shore power and genset when we get set up. Thanks for all the info.

Dave

You can check the outputs of your generator with a multimeter at your transfer switch. This will tell you if your 20A generator breaker is functioning. You'll want to test it under load to ensure that it's not tripping. Just be careful.

My understanding is the same as your's regarding the 20A circuit running compressor #2.

[al1florida]

Originally Posted by BobC

You can check the outputs of your generator with a multimeter at your transfer switch. This will tell you if your 20A generator breaker is functioning. You'll want to test it under load to ensure that it's not tripping. Just be careful.

My understanding is the same as your's regarding the 20A circuit running compressor #2.

It looks like to be able to monitor the voltage on the 20A CB when compressor #2 tries to turn on, you will either have to monitor the voltage on the A/C, at the generator or see if there is another outlet somewhere attached to the 20A CB.

Assuming you are correct in that the 20A CB runs the generator, then checking for loose connections at the transfer switch where the 20A CB comes in, as well as loose connections at the 20A CB.

I seems that the circuitry that feeds compressor is different when the generator is running than when on shore power. That makes troubleshooting a bit more complex. Assumptions up to now are most likely assuming the circuitry is being fed by a single 30amp source through the transfer switch on either shore power or gen power. I know I did.

[Armydave]

Thanks everyone for your help. We are on the road. Here's what I have discovered. When on generator power, the fan comes on and compressor #1 kicks on as it should. Amps are within range. Then I here a click on the thermostat when it is trying to kick on compressor #2 and the amps don't jump at all. it just settles in to about 13 or 14 and runs #1 only. Not experienced in checking the electrical but thinking about having a repair guy replace my 20 amp breaker on my 5500 onan. I had a guy test the output a few months ago but not sure if he looked at each breaker independently. Any thoughts? Again, thanks for all your input. I think im getting close. These basement airs are touchy I guess.


Dave

[Armydave]

Forgot to say that it is functioning perfectly on shore power. Thanks

[al1florida]

Originally Posted by Armydave

Thanks everyone for your help. We are on the road. Here's what I have discovered. When on generator power, the fan comes on and compressor #1 kicks on as it should. Amps are within range. Then I here a click on the thermostat when it is trying to kick on compressor #2 and the amps don't jump at all. it just settles in to about 13 or 14 and runs #1 only. Not experienced in checking the electrical but thinking about having a repair guy replace my 20 amp breaker on my 5500 onan. I had a guy test the output a few months ago but not sure if he looked at each breaker independently. Any thoughts? Again, thanks for all your input. I think im getting close. These basement airs are touchy I guess.


Dave

I can understand your frustration in trying to troubleshoot the problem. Even if you had called a mobile RV tech (or take it to a RV repair replace) your guess is as good as mine if the average tech could find the problem quickly. How many would have any idea that compressor #2 is fed by a 20amp CB on the generator for example. BTW, this setup is most likely unique to specific lines and manufacturing year range of RV. This makes problems much more difficult to diagnose.

Your statement "These basement airs are touchy I guess." may be part of the reason why Winnebago stopped installing basement air.

NOT because they are poor performers, or actually have more problems than 2 roof air conditioners. More likely that since they are unique and require more skill (read higher paid and much better trained RV technicians) to diagnose and repair. This leads to consumer complaints and frustration, giving the system a bad name.
With roof A/C if one breaks, any halfway competent technician can check the start and run capacitors, replace a motor, or if the compressor is locked up, replace the entire roof air conditioner. They only cost a few to several hundred dollars plus the labor to swap out.
The basement air costs about $2500, is hard to access and if one compressor locks up it takes qualified air conditioning skills to repair. Also you need specialized air conditioning tools to do the repairs.

Having had a travel trailer, a 5th wheel, a 40' diesel pusher (with an air conditioner on the roof right over our bed waking us up every time the compressor turned on), a Class C and a Class A all with roof air conditioners, this RV we now have with basement A/C is the first air conditioning system I like.

Now if I have difficult problems with my basement A/C I may be frustrated as well.

[Indy Bob]

If you figure this one out involving the generator and AC, maybe someone can figure why my electric steps go out when I start my generator?

[winnie32v]

Check your wiring diagram.
When on shore power, your intelligent monitoring system will sense both compressors and show the amps when the 1st compressor kicks on, then about 20 sec later it will show the 2nd compressor kick in with the expected ADDITIVE amps of both compressors.
When on generator, the intelligent monitor will sense the 1st compressor kick in, BUT will NOT sense the second compressor due to the 2nd compressor wiring Not going through the intelligent monitoring system .
You will see around 12 - 14 amps on the monitor.
Best way to confirm is to "listen" for the 2nd compressor.
Your wiring diagram will show the 2nd leg in the breaker box, bypassing the monitor.

Less us know what you find out.

[NeilV]

Originally Posted by Armydave

Thanks everyone for your help. We are on the road. Here's what I have discovered. When on generator power, the fan comes on and compressor #1 kicks on as it should. Amps are within range. Then I here a click on the thermostat when it is trying to kick on compressor #2 and the amps don't jump at all. it just settles in to about 13 or 14 and runs #1 only. Not experienced in checking the electrical but thinking about having a repair guy replace my 20 amp breaker on my 5500 onan. I had a guy test the output a few months ago but not sure if he looked at each breaker independently. Any thoughts? Again, thanks for all your input. I think im getting close. These basement airs are touchy I guess.


Dave

Your 2004 should operate the same as my 2001 with the transfer switch powering both compressors from the single 30 amp feed from the power cord and splitting things up when on the generator with the first leg of the transfer switch and the 30 amp breaker on the generator feeding the main electrical panel and compressor #1 in the Basement Air and the second leg of the transfer switch feeding the 20 amp breaker on the generator through to the #2 compressor.

If the 20 amp breaker on the generator is passing power through to the transfer switch and the transfer switch is not passing it through to the #2 compressor then you need to have the transfer switch serviced. It power is not coming out of the 20 amp breaker mounted on the generator then that 20 amp breaker needs to be replaced.

There is no need for guess work and resorting to just throwing parts at it. Any entry level tech should be able to check this out with a basic V/OHM Meter.

Note that voltages should be checked under load too since a bad connection or contactor might show correct voltage when there is no load applied however can drop to the single numbers when a load is applied.


Yes the transfer switches are known to fail on just one side causing these types of symptoms.

[peggwn]

Hey, Armydave,

Neverenuff and NeilV have both mentioned looking at the ATS, and I would suggest the same. Earlier this year we had a problem very similar to yours in that only A/C #1 would kick in. Until then, #1 would start and settle at around 13 Amps; #2 would kick in and settle at about 22-23 Amps. Then #2 began showing symptoms similar to yours and would not run. So, I simply turned off the breaker for #2 and only ran #1. Worked fine for several months.

Then we had an incident with our ATS - it shorted and burned the wires coming in from shore. The tech who came out patched a bypass for us to get our electricals, and more importantly our A/C going until we could get home and replace the ATS.

He asked if we tighten the connections each year. Uh, NO. I had not even thought about it nor did I realize it was a thing to do on a regular, much less, annual basis. He said the connections can become loose and short and burn up the wires adjacent - which it did. I have a new ATS and plan to work on the replacement in a couple of weeks.

Incidentally, even though we run 30 Amps we had a 50 Amp ATS, so I bought one that most closely resembled the original for a replacement - Elkhart LPT50BRD 50 Amp Automatic Transfer Switch for about $180 on Amazon.

In the meantime I've noticed other intermittent problems, probably related to the other unburned ATS connections. So we have shut down the old gal for now until the replacement. I suspect, and sincerely hope, the swap-out will fix things so I can avoid the wrath of SWMBO. Anyway, checking the ATS connections maybe worth exploring as well.

[Armydave]

Thanks everyone. We are back home and I will strt testing the things that were suggested. I will post what I find.

Thanks again,

Dave

[Armydave]

Update on the basement air. I checked the ATS and it seems to be working properly. Tightened all connections and tested under a load as well as not. Numbers stayed steady. I have ordered a new 20 amp breaker for the generator. I will replace that when it arrives, If that doesnt fix it i guess I will just have to run on compressor #1 when on the genset. I will keep ya updated. Thanks for all the help.

Dave

[para566]

I have a 2005 35A Adventurer that this last weekend started doing the exact same thing yours is doing, never had any problems till last friday, & like you everything is checking out fine, so please keep us updated if the 20amp fixes it then I know what I need to do !!

[Armydave]

Para566,

Ill let ya know. Ordered the breaker yesterday so may be a week before I can get installed. Crossing my fingers that this works because if not Im out of ideas.

Dave