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Start-up and Operation
High voltage protection (HP1, HP2)
A high voltage switch gear is provided to protect the water chiller. When high voltage exceeds
602±22psig(4.15±0.15MPa), compressor operation is stopped, and when the pressure is dropped
to 479±22psig(3.303±0.152MPa), compressor operation is automatically restored.
Antifreezing function in winter
In winter, when the water chiller is in a standby state, if water temperature is below the winter
antifreezing temperature setting, the water chiller automatically will enter antifreezing operation,
displaying "AP". Therefore, the water chiller power supply in winter shall be switched on even if the
water chiller is in a standby state.
Antifreezing of plate type heat exchanger
In a refrigeration state, in case outlet water temperature is below , compressor shall be closed,
and water pump shall continue to run, displaying "E3".
High voltage protection of plate type heat exchanger
In the case of heating by a single compressor system, when cooling agent pressure at plate side is
over a certain value, the fan or both the fan and compressor shall be closed, displaying "E.
Overload protection of motor
• Compressor motor overload and superheat protection
•
Water pump motor overload protection
• Fan motor superheat protection
• Thermo probe protection
In case the thermo probe fails, an alarm will be sent and the system will be halted.
* As all alarm protection is subject to manual reset, before the system is restored by pressing
the RESET key or being restarted, the failure needs to be eliminated firstly.
Flow protection
In order to prevent too low water flow that may lead to freezing of the evaporator, a flow switch
(or any other flow sensing device) shall be arranged in the water pipe of the evaporator. Its setting
shall meet the requirement that when water flow is below 70% of total design flow of the system,
compressor shall be stopped immediately.
Running operation
Thermo probe (TH1)
Thermo probe (TH1) senses inlet water temperature of the system as a basis of starting or
stopping the compressor under cold and hot states.
