Solenoid valve diagnostics

[Dougiefresh63]

Hi, I have a commercial refrigerating unit with dual cooling zones, 1 a wrapped cold bn and the other a refrigerator space. The 2 are controlled with txv's and solenoid valves. I believe one of the valves are leaking when closed causing repeated pump don cycles. Is there an easy way to find which solenoid valve is leaking through?

[Silhouette]

Check the valve for temperature drop across it, it should be fairly obvious if it is passing!

[Grizzly]

Good point from silhouette,you could also.
If individual l.p. switches are fitted?
which I assume is the case?
Try metering out or just watching which of them activates first?
It depends on your systems, but is there not a service port.
Where you can observe the individual rise in pressure?

Grizzly

[Dougiefresh63]

thanks guys, I didnt think bout the temp drop from the liquid flashing through the valve. I apreciate it. And only one low pres switch controlling the condenser but a good thought. Thanks Griz :D

[Grizzly]

thanks guys, I didnt think bout the temp drop from the liquid flashing through the valve. I apreciate it. And only one low pres switch controlling the condenser but a good thought. Thanks Griz :D

Slightly confused Dougie!



only one low pres switch controlling the condenser


I was looking for LP. control?
What controls or how do the 2 solenoid valves? operate?
Or am I completely on the wrong track here?
Cheers Grizzly:D

[Dougiefresh63]

dual etc's

[nevgee]

If the above diagnostics don't find the offending item, strip the valves and inspect the diaphram faces, if a piece of swarf or simillar has passed thru the valve, then there could be scratches on the teflon surface. The tinyest of scratches can cause the valve to pass. Using a bright light and mag glass will help with inspecting the surfaces. Then replace damaged diaphram and internal parts for an effective repair.

[Dougiefresh63]

If the above diagnostics don't find the offending item, strip the valves and inspect the diaphram faces, if a piece of swarf or simillar has passed thru the valve, then there could be scratches on the teflon surface. The tinyest of scratches can cause the valve to pass. Using a bright light and mag glass will help with inspecting the surfaces. Then replace damaged diaphram and internal parts for an effective repair.
Thanks, and with my eyes these days-- a good magnifying glass would be in order lol.