R407 MHI VRF 3pipe eating compressors !

[M4ttp]

Hi all,

We have recently taken looking after a company with lots of Heavy industries VRF on
407, the few 3pipe systems have been destroying compressors within 12 months one recently in 5 months ! It's only the 3 pipe systems that have the problem and I have been told other sites have had the same issue with these systems -FDCP280HKXRE2A !

Any ideas pleeeease ?????

Matt

[install monkey]

proves theyre ****e! :p

[M4ttp]

They are I hate MHI !!!! But I need to find the customer a solution apparently MHI said these units have a manufacturing fault but I can't find out what's going on at the mo !!!!

[stufus]

Had a few of these a couple of years ago doing the same thing , A few were down to poor installation incorrectly piped on splitters or T pieces but the main case was lack of nitro during install.
And the others were due to the outer jackets having been removed from the comp's and not refitted after compressor changes , these jackets wrap the discharge pipe and compressor and if left off the resonating causes excessive vibration which results in the oil balance line fracturing and killing the pots.

MHI stuff isn't to everyone's taste but even crap gear will last if installed right.

Cheers
Stu

[install monkey]

do an acid test on the duff compressor, suction burn out driers should be fitted, gas charge weighed out and comfirm system charge by measuring pipework, even blocked filters or high heating setpoints can destroy compressors,loose connections in isolators too can add to the fun,aswell as kinked pipes hidden within insulation

[install monkey]

if its a twin compressor then the oil out the other compressor req changing too-i know a lot of people who dont bother but it will bite you in the arse otherwise

[M4ttp]

Thanks for the replies, do you think it would be worth sending a pot back for analysis ?? The guy in the engineering department on site muttered something about oil return problems ???

[stufus]

Sending one back won't do any harm , but more than likely if the problem is with the machinery the manufacturer is unlikely to say so , and well just blame the installation or maintenance....
If there is an inherant problem with oil return and they admit it a software or eprom upgrade may be available FOC.

Cheers
Stu

[M4ttp]

Argh now we have one system that has fractured a capillary pipe that goes to the oil receiver twice in a week ! Swan vestas and a litre of 4star come to mind