Kaysun KEM-30, Owners & Installation Manual

36

11.7 First startup after shutdown

The folowing preparations should be made for re-startup of unit 
after long-time shutdown:
1) Thoroughly check and clean unit.
2) Clean water pipe system.
3) Check pump, control valve and other equipments of water pipe 

system.

4) Fix connections of all wires.
5) It is a must to electrify the machine 12 hours before starup.

11.8 Refrigeration system

Determine whether refrigerant is needed by checking the 

value of suction and discharge pressure and check whether 

there is a leakage. Air tight test must be made if there is a 

leakage or parts of refrigerating system is to be replaced. 

Take different measures in the following two different 

conditions from refrigerant injection.
1) Total leakage of refrigerant. In case of such situation, 

leakage detection must be made on the pressurized nitrogen 

used for the system. If repair welding is needed, welding 

cannot be made until all the gas in the system is discharged. 

Before injecting refrigerant, the whole refrigeration system 

must be completely dry and of vacuum pumping.

Connect vacuum pumping pipe at the fluoride nozzle at low-

pressure side.
Remove air from the system pipe with vacuum pump. The 

vacuum pumping lasts for above 3 hours. Confirm that the 

indication pressure in dial gauge is within the specified scope.

When the degree of vacuum is reached, inject refrigerant into 

the refrigeration system with refrigerant bottle. Appropriate 

amount of refrigerant for injection has been indicated on 

the nameplate and the table of main technical parameters. 

Refrigerant must be injected from the low pressure side of 

system.
The injection amount of refrigerant will be affected by the 

ambient temperature. If the required amount has not been 

reached but no more injection can be done, make the chilled 

water circulate and start up the unit for injection. Make the 

low pressure switch temporarily short circuit if necessary.

2) Refrigerant supplement. Connect refrigerant injection 

bottle on the fluoride nozzle at low-pressure side and connect 

pressure gauge at low pressure side.
Make chilled water circulate and start up unit, and make the 

low pressure control switch short circuit if necessary.
Slowly inject refrigerant into the system and check suction 

and discharge pressure.

 CAUTION

•  Connection must be renewed after injection 

is completed.

•  Never inject oxygen, acetylene or other 

flammable or poisonous gas to the 

refrigeration system at leakage detection 

and air tight test. Only pressurized nitrogen 

or refrigerant can be used.

11.9 Disassembling compressor

Follow the following procedures if compressor needs to be 

disassembled:
1) Cut off the power supply of unit.
2) Remove power source connection wire of compressor.
3) Remove suction and discharge pipes of compressor.
4) Remove fastening screw of compressor.
5) Move the compressor.

11.10 Auxiliary electric heater

When the ambient temperature is lower than 2°C, the 

heating efficiency decreases with the decline of the outdoor 

temperature. In order to make the air-cooled heat pump 

stably run in a relatively cold region and supplement 

some heat lost due to de-frosting. When the lowest 

ambient temperature in the user’s region in winter is within 

0°C~10°C, the user may consider to use auxiliary electric 

heater.
Please refer to relevant professionals for the power of 

auxiliary electric heater.

11.11 System antifreezing

In case of freezing at the water-side heat exchanger 

interval channel, severe damage may be caused, i.e. 

heat exchange may be broken and appears leakage. This 

damage of frost crack is not within the warranty scope, so 

attention must be paid to antifreezing.

1) If the unit that is shutdown for standby is placed in an 

environment where the outdoor temperature is lower than 

0°C, the water in the water system should be drained.

2) Water pipe may be frozen when the chilled water target 

flow controller and anti-freezing temperature senor become 

ineffective at running, therefore, the target flow controller 

must be connected in accordance with the connection 

diagram.

3) Frost crack may happen to water-side heat exchanger 

at maintenance when refrigerant is injected to the unit or 

is discharged for repair. Pipe freezing is likely to happen 

any time when the pressure of refrigerant is below 0.4Mpa. 

Therefore, the water in the heat exchanger must be kept 

flowing or be thoroughly discharged.