Mitsi City Multi 7100 code

[lonemascot]

Mistsubishi City Multi system
Error code 51 7100

Found this on a system that has recently had a compressor, main PCB and inverter PCB replaced.

Is this something to do with dip switches on the outdoor unit?

I'm not really a service engineer I do more of the install side of things so dont laugh at me if its well obvious to you lol.

Cheers

[stuartwking]

Hi lonemascot. It sounds like some one has replaced the outdoor pcb and not set it correctly.
The fault code is system capacity wrong so i am guessing the outdoor pcb is set for wrong size.
If you look at the reverse side of your units cover the outdoor capacity setting should be there.
Set it to what ever the size of outdoor it is,
Hope this helps.

[lonemascot]

brilliant, sounds like a most likely cause. Cheers.

[lonemascot]

yep just had to set the dip switches.

until the unit threw a 4210 code. what an absolute mare that was. the transistor modules behind the main PCB had exploded out their sides.

I now gotta replace those and a diode stack. Dunno if this caused the original compressor failure or vice versa.

cheers for your help

[Thermatech]

If the compressor windings went with a ground fault this will cause damage to the TRM units in the inverter circuit.
Some times the inverter board is also damaged so check for ballanced supply to compressor after you have replace the compenents.