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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a dual zone mini-split heatpump. Older brand made in

Customer Question

I have a dual zone mini-split heatpump. Older brand made in China - company no longer exists. It is failing to start up. One of the two electronic expansion valves continues to click even after the initial startup. I've swapped the coils between the two valves and it's not the EEV coil (same valve continues clicking longer than the other even with the other coil on it.) After the EEV clicks for maybe 10 seconds, the 4-way valve begins clicks in a pattern - 2 clicks within the valve then the relay clicks, then 4 clicks within the valve and the relay clicks, 8 clicks within the valve then the relay clicks. Repeat. While stuck in this cycle the indoor units can be turned on via the remote... but don't start running. I've rapped on the 4way valve with a screwdriver just in case it's stuck... no change. On the rare occasion that it starts properly, it runs for awhile (cooling fine) but eventually the indoor units shut down and it begins the 4way valve clicking cycle. I've had 2 techs out who checked the pressure with the system running and the charge is good. When I describe the problem, both admit they don't really work inside mini-splits... not even swap the boards. Because on the RARE occasion that it runs it runs fine, I'd like to fix -rather than invest in a new system.
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello, it is most likely a printed circuit card problem...getting a replacement card might not be possible, you can use a hair drier to warm the printed circuit cards up one at a time, to 120F or so. if you get any change at all in behavior, the card is bad.