$500+ basement air still not working

Fletcher0077 · 07-08-2013, 12:18 PM

5 weeks ago while preparing for a long trip I turned on the Air Conditioner with 50A shore power. It tripped both 20A ckt breakers. Tried again, tripped again. Removed AC unit (thanks Duner for your excellent pics). Found Out Door Blower Motor had shorted out internally. The coach is 10yrs old so didn't think much about it. Replaced motor, tried with generator worked fine. Also 20 min running on 50A svc worked fine. Replaced AC...job done.
AC ran fine on generator for 5 days of boondocking and 2 days 30A svc in Reno, NV. Arrived in Idaho 100 deg temps. Plugged into 50A svc and AC ckt breakers tripped. Tried again with generator, ran fine. Tried again with 50A svc and heard arcing from AC and tripped breakers. Pulled out AC, ODBM shorted. Bought a new one and installed.
Tried generator, AC ran fine. Tried 50A shore power tripped breakers. Tried Generator ran fine. Tried 50A again watching Amps at AC input. At AC start on 50A svc amps were normal for 10-15 seconds then one leg dropped to 0A and the other leg went to 20, 30, 35 amps. shut down AC ASAP. Tried generator and AC ran fine. Motor ran fine, probably just bruised a little from 50A try. There is no 30A svc in this parking space. I and a local electrician checked out the 50A supply. All good.
Anyone have any idea why AC would work fine on Generator and 30A svc but over load ODBM on 50A.
All else in coach runs fine on 50A, micro wave, water heater, coffee maker and outlets.
I hope I'v made sense with this long post. Any ideas are greatly appreciated.

edgray · 07-08-2013, 01:20 PM

Quote:

Originally Posted by Fletcher0077

5 weeks ago while preparing for a long trip I turned on the Air Conditioner with 50A shore power. It tripped both 20A ckt breakers. Tried again, tripped again. Removed AC unit (thanks Duner for your excellent pics). Found Out Door Blower Motor had shorted out internally. The coach is 10yrs old so didn't think much about it. Replaced motor, tried with generator worked fine. Also 20 min running on 50A svc worked fine. Replaced AC...job done.
AC ran fine on generator for 5 days of boondocking and 2 days 30A svc in Reno, NV. Arrived in Idaho 100 deg temps. Plugged into 50A svc and AC ckt breakers tripped. Tried again with generator, ran fine. Tried again with 50A svc and heard arcing from AC and tripped breakers. Pulled out AC, ODBM shorted. Bought a new one and installed.
Tried generator, AC ran fine. Tried 50A shore power tripped breakers. Tried Generator ran fine. Tried 50A again watching Amps at AC input. At AC start on 50A svc amps were normal for 10-15 seconds then one leg dropped to 0A and the other leg went to 20, 30, 35 amps. shut down AC ASAP. Tried generator and AC ran fine. Motor ran fine, probably just bruised a little from 50A try. There is no 30A svc in this parking space. I and a local electrician checked out the 50A supply. All good.
Anyone have any idea why AC would work fine on Generator and 30A svc but over load ODBM on 50A.
All else in coach runs fine on 50A, micro wave, water heater, coffee maker and outlets.
I hope I'v made sense with this long post. Any ideas are greatly appreciated.

The common problem in all the scenarios above seems to be the shore power. You say you and an electrician "checked out" the 50A shore power and determined it was OK, but have you tried your A/C on a DIFFERENT 50 amp shore connection elsewhere? My Progressive HW50C would not allow current from a pedestal, and a CG "electrician" assured me their power was good. It wasn't. His "testing" did not find the open neutral, he saw 2 hot legs and a ground and thought that was all that is needed

. If yours ran fine before, and on genset, then I'd be real suspicious of the power where you had the problem. I'd find a new 50A connection and try again before assuming the problem is internal.

Fletcher0077 · 07-08-2013, 06:40 PM

I also have a Progressive 50A unit model EMS-PT50C that I plug into the shore power. It indicated a "EO" condition which is "normal condition". Watching it the first time here at park in Idaho I did also see one line go to 0A and the other leg start going to 35A plus.

The first time it failed was in OR at home. I wired the plug my self. Two 110V hots, one neutral and a ground. 220V between hots and 110v from each leg to ground and neutral. I did the same checks here in Idaho. I pulled the cover and checked breakers and even had them replaced. I also went around the park and checked 4 other 50A plugs and they all look good

One difference I know of is generator and 30A are on the same phase on the 110V. You do not get 220V between the hots as you do with 50A svc. And it works great on 30 amp.

I wonder if this could be a problem with the transfer switch or the transfer switch or maybe the ckt board on the AC unit.

We are in the coach now, 95 degrees outside with gen on. AC working fine. But park manager may come over at any time and tell us to shut down the gen set. May try to get a 30 svc parking place but still need to fix the AC.
Thanks again for your reply. it still could be the 50A svc just don't know how.

John Hilley · 07-08-2013, 08:51 PM

I would check out the transfer switch. Check all connections to be sure they are tight.

Duner · 07-09-2013, 12:59 AM

Quote:

Originally Posted by Fletcher0077

5 weeks ago while preparing for a long trip I turned on the Air Conditioner with 50A shore power. It tripped both 20A ckt breakers. Tried again, tripped again. Removed AC unit (thanks Duner for your excellent pics). Found Out Door Blower Motor had shorted out internally. The coach is 10yrs old so didn't think much about it. Replaced motor, tried with generator worked fine. Also 20 min running on 50A svc worked fine. Replaced AC...job done.
AC ran fine on generator for 5 days of boondocking and 2 days 30A svc in Reno, NV. Arrived in Idaho 100 deg temps. Plugged into 50A svc and AC ckt breakers tripped. Tried again with generator, ran fine. Tried again with 50A svc and heard arcing from AC and tripped breakers. Pulled out AC, ODBM shorted. Bought a new one and installed.
Tried generator, AC ran fine. Tried 50A shore power tripped breakers. Tried Generator ran fine. Tried 50A again watching Amps at AC input. At AC start on 50A svc amps were normal for 10-15 seconds then one leg dropped to 0A and the other leg went to 20, 30, 35 amps. shut down AC ASAP. Tried generator and AC ran fine. Motor ran fine, probably just bruised a little from 50A try. There is no 30A svc in this parking space. I and a local electrician checked out the 50A supply. All good.
Anyone have any idea why AC would work fine on Generator and 30A svc but over load ODBM on 50A.
All else in coach runs fine on 50A, micro wave, water heater, coffee maker and outlets.
I hope I'v made sense with this long post. Any ideas are greatly appreciated.

In reading your post, I was trying to figure out what cost $500+. Reading it a second time I figured out that ODBM is the OutDoor Blower Motor......you had to replace it twice??? Wow! it's got to be 220v getting to the motor caused by a open/loose neutral wire or bad contactor in the transfer box. I think you might be able to see a bad contactor if it's corroded or has fried contacts.

I hard wired my Progressive 50 amp EMS after the transfer box so that it would protect problems from either the genny or shore power or the transfer box. I also have a 50 amp Hughs Autoformer to make sure the voltage is good when it's a hot day and everybody in the campground have their A/C on and the volts are down to 104vac or worse. That low voltage is very hard on the compressors and starting capacitors. It will drastically reduce the life expectancy of those parts.

Hope you get this fixed before the next heat wave!!!

Bill

Fletcher0077 · 07-09-2013, 07:34 PM

Thanks Duner and John for your input. I contacted the folks that built the transfer switch, Parallax Power Components. The Tech I talked with knew his business. We went through some trouble shooting and found nothing wrong with the switch. He said the symptoms are that of loosing the neutral in the 50A ckt when the load goes up as with the airconditionar. Small loads work fine as it dosen't stress the bad connection/breakdown where ever it is. He had good things to say about the Progressive units and said that if that tool said the shore power was good that was good enough for him.
This park in Pocatello, ID "Cowboy RV" has been great to work with with. We are staying 3 more weeks and they are going to install 30A svc so I can run the AC. They are a GoodSam park.

bruceisla · 07-09-2013, 07:48 PM

I'm inclined to think you have a bad neutral. When checking tightness of connections (with power off of course), loosen each connection 1/2 turn before retightening. This will allow you to detect a seized screw caused by excessive heat. Otherwise, with a seized screw, you can get a false sense that the connection is tight.

Fletcher0077 · 07-10-2013, 03:41 PM

Thanks bruceisla. Havent got to check the tightness of the connections yet. Park did install 30A hookup and AC is running fine at 14 amps on one leg and 11 amps on the other, 25A total which is what the Winne power line EMS indicates. Not much left for the coffee pot but it's cool in the mornings.
I'm wondering why 30A works fine (split single phase) and 50A dosen't (2 phase). They both use the same neutral. It seems if the neutral was bad while on 30A the AC would shut down or at least show lower voltage but with AC running now for 3/4 hour each leg is showing 118V. No load indicates 122V.
Still working on the problem but cooler now.

edgray · 07-10-2013, 07:22 PM

Quote:

Originally Posted by Fletcher0077

Thanks bruceisla. Havent got to check the tightness of the connections yet. Park did install 30A hookup and AC is running fine at 14 amps on one leg and 11 amps on the other, 25A total which is what the Winne power line EMS indicates. Not much left for the coffee pot but it's cool in the mornings.
I'm wondering why 30A works fine (split single phase) and 50A dosen't (2 phase). They both use the same neutral. It seems if the neutral was bad while on 30A the AC would shut down or at least show lower voltage but with AC running now for 3/4 hour each leg is showing 118V. No load indicates 122V.
Still working on the problem but cooler now.

Glad you got a work-around with the 30A service. Please excuse my ignorance-I'm not an electrician- but I thought a 30A service was one + lead, one - lead, and a ground; while a 50A (four wire) service was 2+ leads, one - lead aka "the neutral", and a ground. IF this is correct, would that explain why you are fine on 30A, but not on 50A?
Ed

chall · 07-10-2013, 08:00 PM

I have a 2000 35u adventure an when the a/c comes on it will drag the generator all the way down an kick it off. When its plugged in it does the same thing. Had to run the coach a/c over the weekend just to cool off. The amp meter will go all the way up to 49 an back down to 4. Any help would be great. Thanks, Chuck

bruceisla · 07-11-2013, 04:55 AM

Quote:

Originally Posted by chall

I have a 2000 35u adventure an when the a/c comes on it will drag the generator all the way down an kick it off. When its plugged in it does the same thing. Had to run the coach a/c over the weekend just to cool off. The amp meter will go all the way up to 49 an back down to 4. Any help would be great. Thanks, Chuck

Unfortunately, it sounds like a bad compressor. Does it run ok in "fan only" mode?

bruceisla · 07-11-2013, 05:05 AM

Fletcher,

You may want to check the resistance (with an ohmmeter) all the way from the plug to the transfer switch and then from the transfer switch to the distribution panel. Check all 4 wires.

HD4Mark · 07-11-2013, 05:15 AM

Just for some info on your Parallax transfer switch. Ours had the neutral either become loose or burn out in the strip where the wiring is connected between the switch and and shore power. We lost many appliances and electronics that thankfully were covered by insurance. The replacement model ATS501 does not have this type connection.

I would suggest that you try disconnecting from shore power, leave off the generator and give the wires a tug. Check the middle most connections on that strip where is looks like two separate block come together.

If it looks burned or corroded this is the best deal I could find on our new one. PARALLAX ATS501 50 AMP 120/240 VAC AUTOMATIC LINE / GENERATOR TRANSFER SWITCH

BTW we also replaced our OD blower motor, upgraded the squirrel cage and replaced the carrier bearing with a ball bearing model with the help of Duner's write up. Thanks again to Duner.

bachler · 07-11-2013, 07:32 AM

I would like to share my experiance'' We have several rentals.. on one of them In the gerage I put a temp; electric wire.. 40 amp. main then split to 4 15 amps. One of the 15 Legs the tennant Pluged an electric heater in it;; It would blow if he used any other tool with it.. His thought was The 15 amp draw would not trip the breaker if it was not of full power. There are several things to consider.. Altho the breaker states 15 amps It was a duty cycle of .75%, Which will trip.; and the second most important thing, On our testing. if you take a circute; Say50 amps (any amps) every time it is tripped/overloaded The carring capicity goes down; what may be marked at 50 amps when new, after it has been tripped 100 times it's carring/trip/overload will BE lessened to about 37 amps.. The problem lies in the camper thinking the breaker reads 30 amps he puts that much load it trips. (he thinks well I"M paying for it..) The bottom line is A 50/20 amp. breaker will NOT be what they are stated (in used state) WE have had tennents in our RV. park till us we had a wiring problem because it tripped at 2;00 AM; We all knew it was there Heat pump. Kicking on. They were Trying to Suck a bit more out of us... Common sense Is the KEY... Life is good When we all pay our share;;

DancinCampers · 07-11-2013, 07:58 AM

chall, I would check the compressor start capacitors, (black), and the little square device on top of the start capacitor.