compressor fault?

[Putns]

Hello!
I'm new here but urgently need help... Please...
I got Mitsu outdoor unit PUHZ RP71 out of order. It tries to start, but shuts down in few seconds. LEDs are showing that there is commpressor overcurrent. So wanted to ask, how to test the compressor to find out if its ok or there is some probs on board?
unit is 1ph but compressor works on 3ph. so the question is can i somehow test and are these 3 ph x220 and will it blow if i check with 380.
Sorry if question is stupid, but got noone to ask :confused:
And thanks in advance!

[hyperion]

The compressor is an inverter driven type, which will not work on 3phase 380-415 volts as they are designed to work on square syne wave. The overcurrent could be caused by the compressor starting to seize up, there may be a blockage in the refrigerant circuit or potentially an electrical supply problem in the inverter board. Proceed with care when testing the inverter circuit as there are large capacitors which hold their elctrical charge for quite a while.

[Putns]

The point is that i can't find any parameters of this compressor... its only written that its 1200W and made in Japan :]

[hyperion]

You could try the link below to Mitsubishi http://global.mitsubishielectric.com/company/corp/offices/index.html
They may be able to help you.

[Putns]

Thank you Hyperion, but there also is no word about it...

[hyperion]

I think that you need to contact the nearest Mitsubishi help desk, they will be able to advise you on the correct method of testing the compressor electrics etc.

[Yuri B.]

Hello!
Like you I also dont have much experience with invertors and Mitsubishi's VRFs - and like you am from LV.
Have you, leads taken off the motor, measured windings' resistances? (and megger tested in relation to ground)

[Yuri B.]

This (link to the) handbook may turn helpful to you
http://www.mitsubishi-aircon.co.uk/displayfile.asp?id=94723

[Putns]

Thank you for link. windings' resistances are ok... :[

[dogma]

Hey mate. Are there 3 or 4 pins on the compressor????

If it has 4 pins check the resistance between each pin. 1-2, 2-3, 3-4 should all be the same and at 1 ohm or above. 4-1 should be 75% of the valve between one of the others. Some compressors will show this reading at below 1 ohm and can be quite ok.... If the compressor is gone, change out the main power board as well. 9 times out of 10 if you unplug the compressor, reset the fault codes and turn it on, the unit will operate, (condenser fan will come on, indoor fan will come on etc) and will usually mean the Main pcb is fine, If it's not you should get a led error corresponding to the pcb.

If the compressor is ok, test the capacitors.... but be very careful when discharging them. I've had units show a compressor fault when it's been the condenser fan motor drawing the "overcurrent", in which case you'll need a new full set of outdoor boards as well as the fan motor.


Hope this helps....