Thermal Insulation Of Refrigerant Piping - Mitsubishi Electric CITY MULTI PQRY-P250 Installationshandbuch

Warning:
When installing or moving the unit, do not charge it with refrigerant
other than the refrigerant (R407C) specified on the unit.
- Mixing of different refrigerant, air, etc. may cause the refrigerant cycle
to malfunction and result in severe damage.
Caution:
• Use a vacuum pump with a reverse flow check valve.
- If the vacuum pump does not have a reverse flow check valve, the
vacuum pump oil may flow back into the refrigerant cycle and cause
deterioration of the refrigerator oil and other trouble.
• Do not use a charging cylinder.
- Using a charging cylinder may cause the refrigerant to deteriorate.
• Do not use the tools shown below used with conventional re-
frigerant.
(Gauge manifold, charge hose, gas leak detector, check valve,
refrigerant charge base, refrigerant recovery equipment)
- Mixing of conventional refrigerant and refrigerator oil may cause
the refrigerator oil to deteriorate.
- Mixing of water will cause the refrigerator oil to deteriorate.
- R407C refrigerant does not contain any chlorine. Therefore, gas
leak detectors for conventional refrigerants will not react to it.
• Manage the tools more carefully than normal.
- If dust, dirt, or water gets in the refrigerant cycle, the refrigerator oil
will deteriorate.
• Do not insulate gas or low pressure pipe and liquid or high
pressure pipe together.
A
Bad example
B
Good example
Note:
No heat insulation must be provided for electric wires.
16
A Liquid pipe
B
B Gas pipe
C Electric wire
C
D Finishing tape
E Insulating material
D
E
E E
A Liquid pipe
B Gas pipe
A
D Finishing tape
E Insulating material
D
7.5. Thermal insulation of refrigerant pip-
ing
Be sure to give insulation work to refrigerant piping by covering liquid
pipe and gas pipe separately with enough thickness heat-resistant
polyethylene, so that no gap is observed in the joint between indoor unit
and insulating material, and insulating materials themselves. When in-
sulation work is insufficient, there is a possibility of condensation drip,
etc. Pay special attention to insulation work to ceiling plenum.
B
A
D
A Steel wire
B Piping
C Asphaltic oily mastic or asphalt
D Heat insulation material A
E Outer covering B
Glass fiber + Steel wire
Heat
Adhesive + Heat - resistant polyethylene foam +
insulation
material A
Adhesive tape
Indoor Vinyl tape
Outer
Floor exposed Water-proof hemp cloth + Bronze asphalt
covering B
Outdoor Water-proof hemp cloth + Zinc plate + Oily paint
Note:
When using polyethylene cover as covering material, asphalt roof-
ing shall not be required.
• Be sure to fully insulate connecting portion.
A
C
E
A These parts are not insulated.