Mitsubishi Electronics PUHY-HP-THMU-A Thermal insulation of refrigerant piping, Thickness

Note:

•Always add an appropriate amount of refrigerant. Also always charge the system with liquid refrigerant.

•Use a gauge manifold, charging hose, and other parts for the refrigerant indicated on the unit.

•Use a graviometer. (One that can measure down to 0.1 kg [3 oz].)

•Use a vacuum pump with a reverse flow check valve.

(Recommended vacuum gauge: ROBINAIR 14830A Thermistor Vacuum Gauge)

Also use a vacuum gauge that reaches 65 Pa [abs] [0.0943 psi/0.5 Torr] or below after operating for five minutes.

[Fig. 10.3.3]

<If the cylinder does not have a siphon pipe, charge with the refrigerant cylinder up- side-down.>

GB

ASiphon 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]

B A C

DE

A	Steel wire	B	Piping
C	Oily mastic asphalt or asphalt	D	Heat insulation material A

EOuter covering B

Heat	Glass fiber + Steel wire
insulation	Adhesive + Heat - resistant polyethylene foam + Adhesive tape
material A
Outer	Indoor	Vinyl tape
	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]

A	B	E	E
	C	B	A
E	D		D
A Liquid pipe		B Gas pipe	C Electric wire
D Finishing tape		E Insulator

[Fig. 10.4.3]

3Refrigerant Charging

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 refriger- ant by turning the cylinder upside-down as shown in Fig.10.3.3. If the cylinder has a siphon pipe like that shown in the picture on the right, the liquid refriger- ant 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 re- frigerant remaining in the cylinder.

A

Penetrations

[Fig. 10.4.4]

	(Unit: mm [in])
<A> Inner wall (concealed)	<B> Outer wall

A B	C	D
		A B
<C> Outer wall (exposed)	<D> Floor (waterproofing)

	D
EB	F
I	G
	B

<E> Roof pipe shaft	<F> Penetrating portion on fire limit and
		boundary wall
G	I
D		J
B

H
F	A
	1000	1000
	[39-3/8]	[39-3/8]

A Sleeve		B Heat insulating material
C Lagging		D Caulking material
E	Band	F	Waterproofing laye
G	Sleeve with edge	H	Lagging material

IMortar or other incombustible caulking

JIncombustible heat insulation material

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 mate- rials 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:

	Pipe size
	ø6.35 to 25.4 mm [1/4 to 1 in]	ø28.58 to 41.28 mm [1-1/8 to 1-21/32 in]
Thickness	10 mm min. [13/32 in min.]	15 mm min. [19/32 in min.]
Temperature Resistance	100°C min. [212°F min.]

*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.

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