10.4.2. Transferring (Using New Refrigerant Piping)
1.Removing the unit
a.Collecting the refrigerant into the outdoor unit by pumping down
The refrigerant can be collected into the outdoor unit (pumping down) by pressing the TEST RUN button, even when the temperature of the room is low.
•Check to make sure that the valve stems of the
•Press the TEST RUN button on the indoor unit, and allow preliminary operation for
•After stopping the operation, let the unit sit for about 3 minutes, then close the
•Press the TEST RUN button on the indoor unit again, and after
•Tighten the caps of the
•Remove the connection pipes (liquid side and gas side). b. Removing the indoor and outdoor units.
•Disconnect the pipes and connecting electric cables from between the indoor and outdoor units.
•Put capped flare nuts onto all of the pipe connections of the indoor and outdoor units, to make sure no dust or other foreign matter enters.
•Remove the indoor and outdoor units.
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 an R410A AC unit with another R410A AC unit, you should
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 items c) and d) of section About R410A Refrigerant). 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 easy to 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 to the incompatibility of this oil with the R410A, or irregularities may occur in the refrigeration cycle. For this reason, the piping must be thoroughly cleaned, but this is difficult with the present technology.
10.4.4. Refrigerant Compatibility (Using R410A Refrigerant in R22 ACs and Vice Versa)
Do not operate an existing R22 AC with the new R410A refrigerant. Doing so would result in improper functioning of the equipment or malfunction, and might lead to a major accident such as an explosion in the refrigeration cycle. Similarly, do not operate an R410A AC with R22 refrigerant. The chemical reaction between the refrigerating machine oil used in R410A ACs and the chlorine that is contained in R22 would cause the refrigerating machine oil to degrade and lead to malfunction.
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