Hitachi

[thebigcheese]

working with a hitachi utopia ac split indoor rpk 4aq5
suspect blockage after leaving condensing unit. ( me thinks its in the indoor)

what i want to know is what kind off expansion is used in this system and has anyone any tips were to check for a blockage?

cannot remove indoor fascia as some numpty has ran cable tray right along the front of the unit
(still plenty of airflow tho)

[marc5180]

I had a blockage a while back on a mitsi electric split.

From memory the unit used to work on cooling but wouldn't work on heating.

Finally traced the problem to a piece of armourflex that must have gone inside the gas pipe when they were pulling it over the copper on installation.

The way we ended up finding it was disconnect the gas and liquid line going into the indoor and outdoor units and blow through with OFN.

Also then u could blow through the indoor unit to see if it is this that is blocked but most indoors especially cassette types normally have gauze to stop foreign objects going inside the units.

Also had it on another site and we had to seperate the pipework into sections and blow though, we found a 1/4 liquid line was 90% braized inside causing a massive restiction.

[thebigcheese]

this is a high wall unit i put a trace down and didnt get much back thats why im thinkin indoor

[Thermatech]

The Utopia indoor units are compatable with VRF Set Free so have electronic expansion valve at the indoor unit.
Make sure its plugged in at the circuit board.
If you have service manual you can display the indoor unit electronic expansion valve opening possition on the outdoor unit circuit board display, but remember this is the command from the indoor circuit board not the actual opening possition of the valve.

[thebigcheese]

thanks therma , no manual tho.

[al]

register with hitachi at: http://www.hitachiaircon.co.uk/argws/

good selection of tech manauls here.

alec

[thebigcheese]

thanks al i new giving u that lift would pay off one day

[thebigcheese]

blew it all through and got alot off oil back. no valve inside just capilary.
now working ok