Mitsubishi PUHY 250 VRF R410a

[rootsy]

Customer is having power issues. We are running 16 units off 4 of these condensors, controlled with a G50A etc. Power keeps failing feeding these cond units and customer has to keep resetting each one. I thought auto reset was a standard on these. Spoke to Mitsubishi and the bloke in technical said there is no auto reset function available. I find this hard to believe. Anyone no any different?

[Thermatech]

You can set up auto restart following power failure with dip switch settings at each indoor unit circuit board.

Details in service manual

[rootsy]

Its the outdoor units that are having power issues and the indoor units have their own power supply. Will setting these dip switches at the indoor unit reboot the condensor after power failure then?

[The Viking]

OK,
I will go out on a limb here and assume that these units isn't actually loosing all 3 phases at the exact same time and before they are reset, there are actually fault codes for overcurrent/high winding temps displayed.

If this is the case the only thing we have found to overcome this is power monitoring relays. These will cut out as soon as there is an imbalance of the voltage between the incoming phases. Just connect the relay to cut out the feed to the PCB.

I know that this won't cure the problem (that will have to be done by the electricity board) but it would "auto reset" the systems for you.


The site, it isn't in Windsor or Maidenhead by any chance. (We had a lot of these problems in that area)

[Thermatech]

I never have known any a/c system which can automaticaly turn on the MCB back at the power distributon board after if has tripped.

If the MCB at the power distributon board is tripping then the customers maintenance electrician needs to investigate the cause.

After the power to the outdoor units has been restored then the system should start up again if the auto restart fuction is set at the indoor dips.
Otherwise the systems can be restarted by turning on at the G50.

but

the 3 ph power needs to be switched back on by human hand.

[rootsy]

Thanks guys,

Setting dip switch 9 on SW1 at the indoor units seems to have done the trick. To be honest, we've told the on site guys to find out why power keeps tripping. When they have this power failure all they want to do is reset the mcb etc and expect everything to fire up again. Funny thing is I explained to 4 different guys at Mitsubishi who said this wasn't possible, so thanks guys.