Section 14: Chiller Shut Down
The following procedures must considered when the mini chiller is shut down for long periods of
time:
1. Do not totally disconnect the power supply to the chiller unit. This will allow the compressor
crankcase heater to energise and prevent refrigerant migration during the shut down period.
2. The chiller is most vulnerable at shut down during cold weather conditions where there is a
danger of the water in the pipes freezes up. To help prevent this from happening:
a. Set the chiller into the STANDBY mode (i.e. no mode selection on the controller)
In this mode, the controller will force ON the water pump when the ambient air is lower than
5°C. At the same time, the BPHE anti-freeze heater will also energise to heat up the water.
If the air temperature goes lower than 2°C, the controller will force ON the chiller unit to go into
HEATING mode.
Therefore, the power supply to the chiller unit must not switch OFF.
b. If it is not possible to have the power supply continuously ON to the chiller, then it is
recommended to drain all the water in the system.
An alternative is to pump in glycol solution into the system. The concentration must be
sufficient to cater for the lowest ambient temperature. Refer to Section 9 for guidelines.
Restart
When the chiller unit has idling for long periods of time under winter conditions, it is a good
practice to recheck the water condition in the system. Run the water pump only and check for any
cracking or leakages. If the system has been drained of water, refill and perform air venting.
Check if the crankcase heater has been in operation or not. If not, allow the compressor
crankcase heater to heat it up for at least 8 to 12 hours prior to running it again.
Check also for condensation or ice build-up in the controller box. Wipe dry if moisture is present.
Section 14 Page 149
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