siemens expansion valve

[DEVIL]

Yello

after all the conclusions i believe the expansion valve is defective , and i wouldn't want to replace it for nothing, my question is how much experience do you have with siemens electronic expansion valves, because in the chiller that is with problems, there are 2 (out of 4) that have the same symptom and it's my firs expansion valve of this size that i see in trouble.

so ... did anybody had problems with siemens electronic expansion valves

For the data's to be complete , model MVL661.25-6.3

[nike123]

Why dont you explain symptoms?

[DEVIL]

i have a large pressure loss across the valve , from 15 bar before to 1 bar after when the screw is at 100% and the valve is fully open , and condenser water 20 deg C, and evaporator water at 10 deg C, and it is going to low pressure alarm because the pressure after the valve never rises above 2 bar (refrigerant R407).

[NoNickName]

I have very good experience with polycool valves from Siemens, and never found any one faulty, so far. Not even after many years.
Your symptom is typical of a wrongly set dip switch in the valve box. There is one dip switch which limits the max throughput to 63% of the valve max flow rate. Check that one, before assuming the valve is faulty.
Also, did you go through the whole list of parameters? Are they consistent across the four valves?

[DEVIL]

yes the 63% limit is active, but so it is on the one of the circuit that is running ok, so i didn't gave more attention to the switches.

[NoNickName]

Well, you may try to put it to 100% and see whether this makes a difference. If not, than really some sort of clogging is present.

[DEVIL]

i could but i'm shore that there is less then 2% probability that it is going to work :)