8. General maintenance
Checking the cycling water: discharge the water from the heat exchanger. If the water is dirty, the cooling
efficiency will reduce, at the time, the water in the system should be changed.
8.1 Check of heat exchanger and pipes
8.1.1 Check of evaporator
The dirty surface of heat exchanger will reduce the working efficiency. The material of the SHELL&TUBE
heat exchanger is steel and copper pipe, and the heat exchanger can be used for the water system which has
been treated. In some area, the water quality is very hard, therefore the evaporator will be blocked, and will result
that the system stop because of failure or the operation is not economical. In the condition, please consult the
specialist to get the high quality water.
8.1.2 Check of condenser
In the operation, if the environment air is dirty and the dirt on the condenser is much, please often clean the
condenser. With the dirt condenser, the unit will run under high pressure, as a result, the system will not meet the
satisfied effect. Please clean the coil with soft brush and cool water or ask for the professional person. Do not
clean with hot water or cream. Otherwise, the inner pressure of the system will increase. Before the seasonal
startup, clean the condenser surface. As per the cleanness, confirm the periodic cleaning.
8.1.3 Checking the pipes
The periodic checking of pipes mainly is to remove and clean. And then check the leakage of the welding
gap, the flange, the sealed cushion, the thread type, etc.
8.2 Refrigerant charge
When lack of refrigerant (adjusted on the standard condition: cooling: ambient temperature 35℃, water
outlet temperature 7℃; heating: ambient temp 7℃, water outlet temp 45℃. In running, the liquid sight glass must
be clear.), firstly please check the leakage position and amend it. If there is non-condensing air, firstly evacuate
the system and then add refrigerant.
Procedure of charging refrigerant:
a. Close the compressor discharging valve, condenser liquid supply valve, liquid spray valve(single screw
unit), and separate condenser.
b. Connect the hose with the accumulator, and tighten the nut. Then connect the hose with refrigerant
charging valve, temporarily do not tighten the nut. Open the accumulator valve a little to discharge the air until
the refrigerant go out of the hose, then tighten the nut of hose connector on the refrigerant charging valve.
c. Open the big refrigerant charging valve of condenser slowly. By the pressure drop, fill the refrigerant into
the condenser automatically until it meets the admired volume.
d. After the pressure is in balance (weight of accumulator no change), if the refrigerant still does not meet
the admired volume, heat the lower section of the accumulator to ensure the refrigerant can be charged
continuously. Once it meets the admired volume, stop heating at once and close the valve of accumulator.
e. Close the refrigerant charging valve, and disassemble the refrigerant charging pipe.
f. If one bottom of refrigerant cannot meet the requirement, please change the accumulator, and repeat the
above procedure until it meets the requirement.
g. If lack of refrigerant, and the refrigerant weight in the system is unknown, please perform the No 1, No2
and then start up the unit (liquid supply stop valve had
better not to open largely). Open the refrigerant