City multi trouble

[Harry Trafford]

Ok guys this will be hard to put into words but here goes.
Working on a pury-p300ygma. Unit is cutting out on 1102 high discharge. Have had 2 mitsi engineers down to look at it and have about 40hours of m-net tool readings. We have changed the oil bypass valve(sv1) as its dumping discharge into suction. So we tought anyway.... Then today changed the 4way valve and checked the check valve. Unit runs ok on cooling but cuts out after 6mins on heating. Any ideas????

[install monkey]

5ltr of petrol and a match?

[Harry Trafford]

Have been very tempted to cut the pipes and kick it off the roof. Im going down 2mara to change the compressor.

[install monkey]

make sure you energise the crankcase htr for 24 hrs as the internal bearing needs to expand- otherwise it will give symptoms of a siezed compressor- an old work mate had 3 that were siezed when he started it up- turns out mitsubishi issued a claim that you need 24 hrs - hence the 3 faulty compressors were fine

[Harry Trafford]

Ya i will be running system saturday morning. If it doesnt work i will cry.

[The Viking]

I take it you checked and recalculated the charge?

[Harry Trafford]

Yes frist thing i done, was we cannot make out is y the 1/4" pipe from sv1 can be so hot. The suction to compressor is hot to touch but you can leave your hand on it.(forgot my touch probe)

[marc5180]

Hi, have you sorted it? If not can you upload the monitoring tool data for us to have a look at.

[marc5180]

SV1 and SV2 are your discharge to suction bypass safety valves and by the sounds of it are doing their job if the system is tripping on HP.

A couple of questions;

Have you confirmed at what pressures SV1 and SV2 are opening?
Also have you checked your discharge pressure transducers to confirm they are reading correct?
Is the refrigerant charge correct?
Does it work on cooling main and heating main?
Are the indoor filters and coils clean?

[Harry Trafford]

Its actually high discharge(1102).. How do i upload the m-net data?

[dunmaheadin]

Why do you change the compressor if unit is running in cooling? what's your discharge temp - if the suctions hot you are bypassing into LP - 4 way valve (know you said changed already) possibly overheated when replaced?

[marc5180]

Why do you change the compressor if unit is running in cooling? what's your discharge temp - if the suctions hot you are bypassing into LP - 4 way valve (know you said changed already) possibly overheated when replaced?

Have you confirmed the discharge transducers are reading correct? The fact that SV1 is opening suggest you have HP trouble?

Send the log to my email and I'll have a look through and upload it.

[marc5180]

Have you confirmed the discharge transducers are reading correct? The fact that SV1 is opening suggest you have HP trouble?

Send the log to my email and I'll have a look through and upload it.

Check your email

[skilts]

As the unit works fine in cooling but problems in heating, check LEV3 in BC box

Skilts

[Asbolute]

Sounds like a check valve issue

[Harry Trafford]

Its been brought to my attention that endoflush was used in this system a few years back and they didnt get what they put in back out. (Approx 5litres still in system i think) i think i have located a blockage in a heat exchanger. Ive turned off that unit ant the system has rang error free for the last week. Hotel closes nxt week for a few months so il be breaking into the system to see what i can find.