Mitsi Electric 7kw cassette split issues in heating.

[CraigF]

Hi all,

Went to have a look at a 7kw mitsi electric cassette unit today (PUHZ-ZRP71VHA) store complains unit will not heat effectively. Attached gauges and registered 18 bar discharge. Thought this was a bit low and had had the heads up that it was only installed 1 yr ago by a technician who was an electrician.... So, first things first I pulled out 2.5 kg from a 3.5kg system. Short of gas straight away... Pressure tested and found leakage at all flares. Repaired and vacced to 1.75 torr and recharged with fresh 410A. Ran the unit up in test, the results I got are as follows,

Run amps (total) 5.1a
Air on indoor 18.5c
Air off 32.5c
Comp discharge Temp 47.5c (after one hour running)seemed very cold initially
Discharge pressure 20 bar on the nose.
Suction 8.5bar
Pipe temp on service display 33c
The solenoid on 4 way is operational.

These all seem a little low to me tbh, am I going down the route of compressor or 4 way valve???? Mitsubishi elec don't seem to have many ideas on this, and ran out of time today, any thoughts on a remedy? Or any other points to check?

Thanks in advance!!

[install monkey]

how longs the piperun?

[CraigF]

10m mate. I knew I'd forget to add something!!

[install monkey]

410a inverter system in heating mode discharge pressure typically 27-33 bar, any flashy leds on the outdoor?

[install monkey]

hardwired controller you can interogate operation mode, thermistor temps,comp freq,demand

[install monkey]

https://drive.google.com/file/d/0Bz6...ew?usp=sharing
service manual, theres a quick check to see if its s.o.g

[CraigF]

Any info on how to do the interrogation, I have used some of these before to check amp draw etc but don't have any hard info on this. Didn't take any real record of the LEDS tbh and had no fault codes come up.

[CraigF]

With regards to it being sog I did give it fresh charge 3.5 kg ��

[CraigF]

Good Manual that is, thanks IM

[install monkey]

check dipswitches on outdoor incase the max comp freq hasnt been derated, you can limit it to 25,50,75%

[CraigF]

Still not got back to this unit due to fitting a new unit on another site, will update when I can!