Mitsubishi 4108 fault

[boulting]

Hi,

I have this fault code on a City Multi, I know the fault is something to do with the fixed speed compressor tripping on overload, does anybody know how to get this compressor to run manually so I can check out the run current, i've checked the windings and they are OK.

Cheers

[james10]

Try giving mitsi technical a ring 01707282880
you could also try putting a feed to the contactor coils or simply push the contactor in,also have you checked the comp is getting all three phases ie fuses mains supply
hope this helps

[boulting]

Hi,

Cheers for the info, the only problem is you have to disconnect all the wires from the main board to open the panel and get to the contactors and overload, I've checked the contactor & Overload for continuity and thats OK, I don't want to power the unit up with the main board disconnected.

I'll try Mitsubishi tomorrow.

Cheers

[james10]

the only other way i can think of is if you have an amp clamp with a peak hold function on is to put your lamp on,reset the fault, run the unit and repeat for all three phases

[boulting]

Thanks for that James, I'll give that a go.

Cheers

[Thermatech]

As the windings are ok the compressor could be locked or a problem with the contactor + overload.
I dont think there is any setting on the outdoor unit to bypass or over ride the contactor overload. But the overload is connected to the relay board on most of the larger PUHY-P YMF-C units so you should be able to measure if the overload is operating or not from the relay board & that is on the front panel next to the control board.
You could do a ' no load' test by disconnect the 3 power cables at the compressor. make safe by connecting to a blank terminal block & then run system. Measure the voltage at each 240v power supply cable & 3ph between.
This could give an indication of a problem with the contactor or overload.

If you are brave then make a direct connection from the outdoor unit isolator to the compresor direct.
If the compressor runs at high amps then there is some mechanical problem with the compressor.
If the compressor trips the power supply MCB back at the distributon board then the compressor is locked.
As the MCB should be sized for the system with inverter compressor & fan running & fixed speed compressor starting then if you only direct connect the fixed speed compressor to the power supply the MCB should not trip & the compressor should start & run.
Dont run the compressor like this for more than a few seconds because all the valves in the system will be shut & the discharge pressure will rise very fast & with it the compressor amps.
So take start amps & run amps after a few seconds & then switch off.

Disclaimer / safety warning
Only do this direct on line test if you are qualified & confident working with 3ph as it can kill