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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.
• 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.
CAUTION
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.
Summary of Contents for KEM-HT-65 DRS5
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