Restrictions On Pipe Length - Mitsubishi Electric PUHY-RP200 Service Handbook

[ II Restrictions ]

[8] Restrictions on Pipe Length

1. Determining the reusability of the existing piping
Mitsubishi Electric Corporation cannot be held responsibility for the problems arising from the use of the existing pipes. Before
installing the new air conditioning system, the existing piping system must be checked for refrigerant gas leaks, strength (ma-
terial/thickness), and for corrosion.
Major points to consider when evaluating the reusability of the existing piping
(1) Replacing City Multi units with Replace Multi units
ŒThe existing piping system can be reused unless there have been problems with the system.
(Make sure that the system has not experienced frequent malfunctions due to refrigerant gas leaks or required additional re-
frigerant charge frequently.)
1) Replacing the existing units with Replace Multi units with the same capacity The existing pipes can be used as they are.
2) Replacing the existing units with Replace Multi units with different capacity Make sure that the existing piping system meet
the piping size, piping length, and maximum vertical separation requirements for the Replace Multi system.
(2) Replacing units other than City Multi units with Replace Multi units
1) Make sure that the existing packaged air conditioning system is operating normally.
(Make sure that the system has not experienced frequent malfunctions due to refrigerant gas leaks or required additional re-
frigerant charge frequently.)
2) Find out the type of the refrigerant oil used in the existing system.
Suniso, MS, HAB, Barrel Freeze, and Freol are acceptable. If other types of refrigerant oil is used, check on the compatibility.
3) T-shaped, Y-shaped, and header branch pipes can be reused.
Branch pipes that are subject to pressure loss (e.g., Mr. SLIM multi distributor) cannot be used in the Replace Multi system.
They should be replaced with new branch pipes.
Using the manufacturer name, model name, and the number of units connected to estimate the branching types and pipe
sizes.
4) Make sure that the existing piping system meet the piping size, piping length, and maximum vertical separation requirements
for the Replace Multi system.
Criteria for determining the reusability of the existing piping
Item
Pipe size/length
Refrigerant oil
type
Air tightness
Branch pipe
type
Insulation
Piping system
Radial thickness
of the refrigerant
pipe
WARNING
Do not let refrigerant (R410A) leak in the presence of an open flame or other heat source. If refrigerant comes in
contact with an open flame, it will break down and produce toxic gases. Do not weld in a confined space. Perform a
leak test upon completion of refrigerant pipe installation.
WARNING
When installing or relocating the unit, check that no substance other than the specified refrigerant (R410A) is present
in the refrigerant circuit.
ŒPresence of foreign substance or air can cause abnormal pressure rise or explosion.
CAUTION
Use refrigerant piping made of phosphorus deoxidized copper. Keep the inner and outer surfaces of the pipes clean
and free of such contaminants as sulfur, oxides, dust, dirt, shaving particles, oil, and moisture.
ŒContaminants in the refrigerant piping may cause the refrigerant oil to deteriorate.
HWE10010
Evaluation criteria
Refer to "Restrictions on Pipe Length" and "Refrigerant pipe
size" in the following pages.
Suniso, MS, HAB, Barrel Freeze, and Freol
Pressurize the system to REPLACE MULTI Y(PUHY-RP): 3.3
MPa [479 psi]; REPLACE MULTI R2 (PURY-RP): 3.6 MPa [523
psi], and leave it for a day to check for pressure loss.
T-shaped, Y-shaped, and header branch pipes
Insulation and caulking are not coming off.
The vertical separation requirement is met.
The figures in the radial thickness column are based on the
Japanese standards and provided only as a reference. Use
pipes that meet the local standards.
- 44 -
Other evaluation materials
N/A
Manufacturer, model type/name,
and manufacturing year
Units in the existing system are op-
erating normally.
Manufacturer, model type/name,
and manufacturing year
N/A
N/A
GB