Electronic Expansion Valve Jammed (AKV)

[Y L Lai]

Hi Guys,

Need some help here. Recently, we've installed a system in a supermarket with Danfoss AKV system. It was running fine for about 6 months and suddenly few AKV failed without warning on MT system. DC coil is fine, it says 100% open but looks like no refrigerant flowing through. We dismantled one of the valve and found no particle inside the strainer, orifice not stucked, no blockage on liquid line, and armature looks nice. Assemble it back and it was running ok again.

Does anyone have this kind of prob? Some says oil is the problem. This system is running on POE, R22.

Thanks. Please advice.

Lai

[coolhibby1875]

hi this is a common fault with the danfoss.
first you have to make sure the supa heat is ok if it goes to low this will forcre the valve shut.
and secondly you must insure the coils state akv only, as i have seen some people fit normall valves but these wont work on the danfoss.

[Y L Lai]

Hi Coolhibby,

All controls are ok. Coil is AKV coil. I'm not having problem with controls, but the valve jam. Any experience?

[supermarketguy]

Hi Y L Lai

It is possible that you may have had an intermittent probe problem, on some danfoss controllers the valve shut down if it sees a negative superheat and when you switch it on the problem dissapears and valve operates normally.

Normally the problem returns and faulty probe will show up. What type of danfoss controller is it? is it a AKC or EKC Controller.

Supermarketguy

[Magoo]

Had similar problem on a system several years old, and fitted new piston kits. Solved problem.
magoo

[julius Geezer]

As stated above , check the superheat and check the obvious ...ie suction probe position...good luck...Hail Caesar...!

[Y L Lai]

Hi Y L Lai

It is possible that you may have had an intermittent probe problem, on some danfoss controllers the valve shut down if it sees a negative superheat and when you switch it on the problem dissapears and valve operates normally.

Normally the problem returns and faulty probe will show up. What type of danfoss controller is it? is it a AKC or EKC Controller.

Supermarketguy

As described, S2 no problem, transmitter no prob, superheat no prob. Controller says 100% open, 230VDC Coil ok, but valve remain closed. :mad:

[Yuri B.]

Maybe water in system? I see a heater put on an EEV (not a Danfoss EEV, 24V and some 30W or 40W), dont know was it a specially designed kit or someone had been experimenting.

[supermarketguy]

hi YL

Is there a fault code showing on the display? if not, use a display with the buttons (EKC Controller) and press the top button once and this will tell you what you want to know Hopefully.;)

If you have err on it , it's Toast!!!!!!! and a replacement will be required.

Supermarketguy

[Silhouette]

Check the voltage output from the controller. They sometimes go Kaput!

[HallsEngineer]

I would set your pulse time lower say 3 seconds and see if that makes a difference because as soon as the armature sticks shut the 6 second pulse time only blips off which isn't enough to allow the pressure to build in the port. I would replace armature and armature seat.

[coolhibby1875]

try 1 of those magnet coils on to see if this opens valve or check someone hasnt fitted a valve that closes on being energised i have been caught out with that a few times!