HP - C 3
Electronic Expansion Valve (EEV) Test
Troubleshooting the EEV
The Electronic Expansion Valve (EEV) installed in this
heat pump is designed to control superheat entering
the compressor when the system is running in me-
chanical heating mode. During cooling mode, refriger-
ant flow bypasses the EEV via a check valve and is
controlled by the expansion device in the indoor unit.
Therefore, any operational problems observed in cool-
ing mode are not caused by the EEV.
Note: The EEV closes with every OFF cycle in the
heating mode of operation. During Defrost and in the
cooling mode of operation, the EEV will drive to half
open. An audible sound can be heard when valve is
changing positions.
Table 1
Electronic Expansion Valve (EEV) control board
Status LED (Green) (Figure 2)
On: Control has power.
Flashing fast: Control is driving valve (5 seconds
max. drive time)
Flashing pattern: See Table 1.
Control Input and Status LED - J6
Fault LED (Red) (Figure 2)
Flashing pattern: See Table 2.
Table 2
Note: Verify the suction line temperature sensor and
suction line pressure transducer and reading properly
when troubleshooting the EEV.
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