Battery Back-Up; Troubleshooting - Danfoss EKC 316A Reference Manual

Battery Back-up

A battery back-up can be connected to terminals 5 (+) and 6 (-).
The voltage should be at least 18 Volts and this can be achieved
by using two 9 Volt 100 mAh batteries in series.
The back-up voltage can also come from UPS giving 24 Volts.
Note: In the case where no battery back-up is used, the valve will
always close correctly even when the valve is fully open before the
power is interrupted.
The valve will be driven 110% of the steps during start up.

Troubleshooting

Symptom
Suction pressure too low
Liquid hammer in compressor
EKC 316A
Possible Cause
Pressure drop across the evaporator too
high
Lack of subcooling ahead of expansion
valve
Evaporator superheat too high
Pressure drop across the expansion valve
less than valve is sized for
Expansion valve too small
Expansion valve block with foreign mate-
rial
Evaporator wholly or partly iced up
Superheat of expansion valve too low
Superheat reference set too low
The S2 sensor not in good contact with the
suction line
Reference manual RS8ED102 © Danfoss
Remedy
Check refrigerant ahead of expansion
valve.
If the valve is placed much higher than
condenser outlet, check pressure differ-
ence
1. Check superheat performance, the set-
tings SH min and SH max.
2. Check valve capacity.
3. Check that the maximum number of
steps of valve is same as parameter n37
Check pressure drop across expansion
valve. Replace with larger valve.
Check refrigeration system capacity and
compare with expansion valve capacity.
Replace with larger valve if necessary.
De-ice evaporator
Increase the values of SH close and SH min.
Increase the value of SH min
Ensure that S2 sensor is secured on suction
line. Insulate sensor.
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