Panasonic CU-E18CKR Service Manual page 66

- Press the TEST RUN button on the indoor unit, and allow
preliminary for 5-6 minutes. (TEST RUN mode)
- After stopping the operation, let the unit sit for about 3
minutes, then close the 2-way valve by turning the valve stem
in the clockwise direction.
- Press the TEST RUN button on the indoor unit again, and
after 2-3 minutes of operation, turn the valve stem of the 3-
way valve quickly in the clockwise direction to close it, then
stop the operation.
- Tighten the caps of the 2-way valve and 3-way valve to the
stipulated torque.
- Remove the connection pipes (liquid side and gas side).
2. Installing the unit / Install the unit using new refrigerant piping.
Follow the instructions in section 4.1 to evacuate the pipes
connecting the indoor and outdoor units, and the pipes of the
indoor unit, and check for gas leaks.
10.4.3. AC Units Replacement (Using Existing Refrigerant Piping)
When replacing and R410A AC unit with another R410A AC unit, you should re-flare the
refrigerant piping. Even though the replacement AC unit uses the R410A, problems occur when,
for example, either the AC unit maker or the refrigerating machineoil is different. / When
replacing an R22 AC unit with an R410A AC unit, the following checks and cleaning procedures
are necessary but are difficult to do because of the chemical characteristics of the refrigerating
machine oil (as described in itemsc) and d) of section 10.1.1.(2)). In this case, you should use
new refrigerant piping rather than the existing piping.
1. Piping check / Because of the different pressure characteristics
of R22 and R410A, the design pressure for the equipment is 1.6
times different. the wall thickness of the piping must comply with
that shown in Table 10, but this is not easyto check. Also, even if
the thickness is correct, there may be flattened or bent portions
midway through the piping due to sharp curves. Buried sections
of the piping also cannot be checked.
2. Pipe cleaning / A large quantity of refrigerating machine oil
(mineral oil) adheres to existing pipes due to the refrigeration
cycle circulation. If the pipes are used just as they are for the
R410A cycle, the capacity will be lowered due tothe
incompatibility of this oil with the R410A, or irregularities may
occur in the refrigeration cycle. For this reason, the piping must