Airdale chiller EEV fault?

[almichieuk]

I have a strange problem....

Chiller is an ultima 400kw with Carel pco3 controller and an additional Carel eev driver. It's a sporlon eev. The system had been diagnosed by a n other with a refrigerant leak and possible eev failure.

Recovering the refrigerant 45 of a 65kg charge came out. Leaks were found and repaired.

System charged with virgin R407c. The system behaved as before. It should be noted the driers were changed and the mesh filter was found very dirty and blocked. It was cleaned and re installed - this was thought to be the problem, but not so.

When this circuit starts (3 scrolls per circuit) evap pressure falls quickly then recovers for a short time (max 4 bar) then quickly falls and fails on lp.

The display shows the valve fully open.

Subcool starts off fine but falls away as it runs eventually leading to 0 degrees subcool.

Again superheat starts off fine but ends up over 24 degrees.

I am changing the valve, but I'm not convinced it is the valve that is the problem. The valve windings checkout fine too. I'm wandering if it could be a problem with the plan driver??

I'll keep this updated as work continues...

Thanks in advance!

[almichieuk]

No responses??

Well it was the valve for those that might be interested....

[Brian_UK]

Only just read your post, it may prove to be the answer to a problem I'm having with a Carel E3V valve.

Had to change the stepper motor recently on this circuit, 1 out of 4, and one of the faults is still occuring. It seems to run OK while I'm there but when I next return it has dropped a few 'low suction pressure' alarms.

Will be on site tonmorrow for a general service visit so can watch it a bit more closely.

[goshen]

Hi
what did you find in the valve housing?
or was it the stepper motor?
good luck

[almichieuk]

The actual brass body looked OK TBH, there was no sign of debris or damge to the valve. I didn't change the body as there was no need and it would have introduced carbon into the system.

funnily enough we are on site now carrying out a maintenance visit and the other two chillers have issue with superheat control too. They are (apparantly) flooding back. I wonder if there was a problem with quality control when the machines were built and the mesh/driers aren't holding all of the dirt back from the valve and they are sticking....