Basement ac

[ChewnMilla]

Circuit 1 works fine when on by itself. I have tested all capacitors starters and both compressors and they all test good. When circuit 2 breaker is on it starts up and all fan comes on them the fan runs a min and shuts off. Then the amps start to rise on the panel. Shutting off 1 and just try to run 2 nothing happens. Before I tested everything I started gen and tried to run with both circuits on and it shook the rv lime crazy as the amps increased.with 2 off nothing works with gen on. Cools great with 1 on and 2 off with shore power. Any ideas? Thanks in advance.

[Bikeboy57]

You also might want to check all your electrical connections. I have found wire nuts to be especially problematic in high current applications in the motorhome. Bad connection equal low voltage. If we believe ohms law as voltage decreases amperage will increase blowing the breaker

Also look carefully at the circuit board front and back. You have different brand ac than me, but the board is a weak link because the compressor current runs through the board. Many of the Newell guys with basement air have installed external high current relays to get the amperage off of the board.

[Bikeboy57]

Hard start may keep you going for a while. But do keep an eye on compressor 2.

[ChewnMilla]

Gonna run this by you all. I have started it with both circuits powered and it never shut down. Ran it for 2 hours that way and no problems. When it did finally cycle off it did the same thing it started up just fine then it shut off the fan and amps went up so as amps were climbing I flipped the breaker off and circuit one ran fine and cycled on and off fine. So today it was running when got home so I flipped circuit 2 on while it was running and it has been running fine. I have had my ampprobe on it and 2 hasn't obviously came on after a half hour cause I am only pulling 1.7 and 1 is running a steady 4.4. I had a tech tell me to get a hard start kit and that will fix it. He also told me to change caps so I just swapped them fro. Inside to the other and 1 runs fine with 2s caps.

[jyrostng]

One problem I've found in those basement units that lose a compressor is that they have a internal liquid line filter in one of the last tubes inside the condenser. That filter consist of a felt filter, blow through the condenser with the compressor off, it will be greatly restricted because as the compressor wears, that piece of felt traps all the particles. You have to remove the condenser Utube end pieces and use a wood screw threaded into it to remove it, otherwise it will have high head pressure and cause the new compressor to not work properly. Those units are no longer available and a PIA to remove and reinstall.
7 years ago I posted this: http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/24588428.cfm














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[gfs1943]

Some systems have an inline fuse in the high-speed condenser fan wire (black wire from circuit board to fan). If that fuse is blown, the system behaves just like you described.

When the thermostat is set at one degree below ambient, only system 1 runs. When ambient temp is two or more degrees above thermostat setting, system 1 runs briefly, then the condenser fan shuts off, and system 2 starts. However, if there is no power on the system 2 condenser fan wire (fuse blown), the condenser fan never restarts.

The only workaround I've found for this is to turn off the system 2 circuit breaker. That allows system 1 to run as needed. My experience is that system 1 will keep the temp bearable inside the MH.

I recently replaced the air conditioner circuit board, along with the compressor start and run capacitors, and of course replaced the fuse (again) for the high-speed condenser fan circuit. I also replaced both compressor relays.

I got all the parts from Makarios RV, and was very satisfied with their service. So far, so good!

[Bikeboy57]

If you or a tech will hang an ammeter on the one of the power wires you will probably see that the compressor is pulling excessive amps when trying to start. Somewhere on the unit you should find a placard that details LRA (locked rotor amps). The compressor will need to be replaced. It won't be a hard jobs for an AC tech. The typical RV tech won't touch it since they normally don't repair ACs. The system will need to be evacuated and refilled with refrigerant after the compressor is replaced. Ask the tech if they will use nitrogen when sweating in the new compressor and if they will install a filter drier. If the answer to either question is no, then look for another tech

[ChewnMilla]

Replaced both caps and starters. It still starts and runs the fan for 30 secs or so and shuts off when I have circuit 2 on. Fan goes off and amps go up. I flip breaker off and fan comes on circuit 1 will cycle on and off perfectly. And every once and a while I have 2 on and it stays running fine til it needs to cycle then shuts down.

[Hank_MI]

Also, compressor 2 won't attempt to start with breaker to #1 off. #1 has to be up and running before control will try to start compressor 2. I ran for weeks in Florida on just #1. It did a good job of keeping things cool. Replaced the start caps when we got back home and now #2 works fine.

[Bikeboy57]

The second compressor is locked. The fan motor will come for a second before the compressor starts. When, the compressor tries to start it pulls locked rotor amps and trips the breaker..

[ChewnMilla]

It's been running on just the one compressor just fine for three days. When I turn on the other breaker it shuts down.

[jyrostng]

bad fan motor.