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cold.man
01-11-2013, 11:00 PM
I attended a call to a pack where I found the ICMT valve was stuck in the closed position.
The ICAD was saying the valve was open 83% but the valve was completely shut and pack off on HP.
Vented off the gas cooler and removed the valve found the valve not turning but the ICAD was ok.
Replaced the valve and the ICMT is now operating ok after a while found the valve moved freely seemed to defrost.
Found like a sticky substance inside the valve possibly oil has anyone come across this before.

Thanks
Mark

dvtruc
29-04-2014, 10:20 AM
Ball bearing dirty

Truc

Tycho
30-04-2014, 03:53 PM
haven't seen the valve sticking, but have seen the ICAD loosing it's zero point.

This happened on a system with a large pilot receiver, so when there was no load on the system the valve was operation with opening degrees up to 5%

After a day or two it lost the zero and wouldn't go back to fully closed and the receiver would slowly drain.

We replaced the valve a few times, and the ICAD a few times with no luck.

After many discussions with danfoss they sent us a new ICAD with updated software, or so they said, and it's been working ever since

dvtruc
30-04-2014, 06:01 PM
the opening degrees is mechanical or ICAD digit display. Maybe when working, the valve was sticking in a while and ICAD step motor still kept running then misalignment and it caused zero or 100 loosing. ICAD is open loop control.

Truc

Tycho
02-05-2014, 05:21 PM
the opening degrees is mechanical or ICAD digit display. Maybe when working, the valve was sticking in a while and ICAD step motor still kept running then misalignment and it caused zero or 100 loosing. ICAD is open loop control.

Truc

Ah yes, maybe the valve was indeed stuck and then when the ICAD started turning it made the magnetic coupling slip and thus loosing it's zero point.

With the new ICAD it's working, so I don't know if Danfoss made a new software that spins the ICAD some extra degrees to make sure the valve is really closed and then sets a new zero point.

dvtruc
02-05-2014, 06:48 PM
You better go with Siemens electro magnetic valve, many ones did. No rotating, no bearing so avoiding such problem. I am looking for a small size one working as a pilot with Danfoss servo valve but I failed so far.

Cheers

Truc