Thermal Insulation Of Refrigerant Piping - Mitsubishi Electric Y Series Installation Manual

• Evacuate the system to 1,500 microns from the suction service valve.
- Break the vacuum with Nitrogen (N2) into the discharge service valve to 0 PSIG.
• Evacuate the system to 500 microns. System must hold the vacuum at 500 microns for a minimum of 1 hour.
• Conduct a rise test for a minimum of 30 minutes.
3 Refrigerant Charging
Do not use refrigerant other than the type indicated in the manuals provided with the unit and on the nameplate.
- Doing so may cause the unit or pipes to burst, or result in explosion or fire during use, during repair, or at the time of disposal of the unit.
- It may also be in violation of applicable laws.
- MITSUBISHI ELECTRIC CORPORATION cannot be held responsible for malfunctions or accidents resulting from the use of the wrong type of refrigerant.
Since the refrigerant used with the unit is nonazerotropic, it must be charged in the liquid state. Consequently, when charging the unit with refrigerant from a cylinder,
if the cylinder does not have a siphon pipe, charge the liquid refrigerant by turning the cylinder upside-down as shown in Fig.10.3.3. If the cylinder has a siphon pipe
like that shown on the right of Fig.10.3.3, the liquid refrigerant can be charged with the cylinder standing upright. Therefore, give careful attention to the cylinder
specifications. If the unit should be charged with gas refrigerant, replace all the refrigerant with new refrigerant. Do not use the refrigerant remaining in the cylinder.
[Fig. 10.3.3]
<If the cylinder does not have a siphon pipe, charge with the refrigerant cylinder upside-down.>
A Siphon pipe
10.4. Thermal insulation of refrigerant
piping
Be sure to add 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 insulation work is insufficient, there is a
possibility of condensation drip, etc. Pay special attention to insulation work in
the ceiling plenum.
[Fig. 10.4.1]
C
B
A
D
E
A Steel wire
C Oily mastic asphalt or asphalt
E Outer covering B
Heat Glass fiber + Steel wire
insulation
Adhesive + Heat - resistant polyethylene foam + Adhesive tape
material A
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 roofing
shall not be required.
• No heat insulation must be provided for electric wires.
[Fig. 10.4.2]
B
E
A
B
C
D
E
A Liquid pipe B Gas pipe
D Finishing tape E Insulator
[Fig. 10.4.3]
18
B Piping
D Heat insulation material A
E
A
D
C Electric wire
A
Penetrations
[Fig. 10.4.4]
<A> Inner wall (concealed)
A B
<C> Outer wall (exposed)
E
B
I
<E> Roof pipe shaft
G
D
B
H
F
Sleeve
A
Lagging
C
Band
E
Sleeve with edge
G
Mortar or other incombustible caulking
I
Incombustible heat insulation material
J
When filling a gap with mortar, cover the penetration part with steel plate so
that the insulation material will not be caved in. For this part, use incombustible
materials for both insulation and covering. (Vinyl covering should not be used.)
• Insulation materials for the pipes to be added on site must meet the following
specifications:
ø6.35 to 25.4 mm
Thickness 10 mm min.
Temperature Resistance
* Installation of pipes in a high-temperature high-humidity environment, such
as the top floor of a building, may require the use of insulation materials
thicker than the ones specified in the chart above.
* When certain specifications presented by the client must be met, ensure that
they also meet the specifications on the chart above.
(Unit: mm)
<B> Outer wall
D
C
A B
<D> Floor (waterproofing)
D
F
G
B
<F> Penetrating portion on fire limit and
boundary wall
I
J
A
1000 1000
Heat insulating material
B
Caulking material
D
Waterproofing layer
F
Lagging material
H
Pipe size
ø28.58 to 41.28 mm
15 mm min.
100°C min.