Haier MRV5 Installation Manual page 14

Installation procedure
A. Refrigerant pipe connection
Pipe connection method:
• To ensure the efficiency, the pipe should be as short as
possible.
• Daub the refrigerant oil on the connector and the flare
nut.
• When bending the pipe, the bending semi-diameter
should be as large as possible against the pipe being
broken or bent.
• When connecting the pipe, aim at the center to thread
the nut by hand and tighten it with the double spanners.
• Fastening torque please refers to "pipe specs and
fastening torque" on page 15.
• Don't let the impurity such as sand, water etc into the
pipe. Antifouling measures refer to page 13.
Cautions in piping installation:
1. When welding the pipe with hard solder, charge nitrogen into the pipe against oxidation. The
pressure gauge should be set at 0.02MPa.Perform the procedure with nitrogen circulation.
Otherwise, the oxide film in the pipe may clog the capillary and expansion valve resulting in
accident.
2. The refrigerant pipe should be clean. If the water and the other impurity enter the pipe, charge
the nitrogen to clean the pipe. The nitrogen should flow under the pressure of about 0.5Mpa
and when charging the nitrogen, stop up the end of the pipe by hand to enhance the pressure
in the pipe, then loose the hand (meanwhile stop up the other end).
3. The piping installation should be executed after the stop valves are closed.
4. When welding the valve and the pipe, cool down the valve with wet towel.
5. When the connection pipe and the branch pipe need to be cut down, please use the special
shears and cannot use the saw.
6. When welding copper pipe, use the phosphor copper welding rod without any welding flux.
(welding flux will damage the piping system. The welding flux containing chlorine will corrode
pipe, especially, the welding flux with fluorin will damage refrigeration oil.)
Pipe material and specs selection
1. Please select the refrigerant pipe of the below material.
Material: the phosphoric oxidize seamless copper pipe, model: C1220T-1/2H (diameter is
over 19.05); C1220T-0(diameter is below 15.88).
2. Thickness and specs:
Confirm the pipe thickness and specs according to the pipe selection method(the unit is with
R410A, if the pipe over 19.05 is 0-type, the pressure preservation will be bad, thus it must be
1/2H type and over the min. thickness.
3. The branch pipe and the gather pipe must be from Haier.
4. When installing the stop valve, refer to the relative operation instruction.
5. The pipe installation should be in the allowable range.
6. The installation of branch pipe and gather pipe should be performed according to the relative
manual.
When fastening and loosing the
nut, operate with double spanners,
because only one spanner cannot
execute firmly.
spanner
spanner
If threading the nut as not aiming
at the center, the screw thread
will be damaged, further it will
cause leakage.
12
connector
nut