Hoshizaki HNC-120BA-L-S, Руководство по обслуживанию, Страница: 24 / 26

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pump may be the same as those for the current refrigerants. However, the rubber hose
and gauge manifold to be used for evacuation and refrigerant charge should be exclusively
for R134a.
8) Refrigerant Leak Check
Refrigerant leaks can be detected by charging the unit with a little refrigerant, raising the
pressure with nitrogen and using an electric detector. Do not use air or oxygen instead of
nitrogen for this purpose, or rise in pressure as well as in temperature may cause R134a to
suddenly react with oxygen and explode. Be sure to use nitrogen to prevent explosion.
11. CONSTANT PRESSURE EXPANSION VALVE AND REFRIGERANT
CHARGE
[a] SPECIFICATIONS
Model: HYP-2-5QHD-5
Manufacturer: Fuji
Koki
Part Number: 447283-04
Refrigerant: R134a
Adjustment Range:
0.01 - 0.3MPa
Pressure Rise by Adjusting Screw: 0.039 - 0.049MPa / turn
[b] FUNCTION
When the low side pressure drops, the Constant Pressure Expansion Valve opens and lets
the refrigerant flow to keep a constant pressure.
[c] CONSTRUCTION
Fig. 6
IN (High Pressure)
Needle Valve
Cap
Adjusting
Screw
Adjusting
Spring
Diaphragm
Working
Bar
Inner Spring
OUT (Low Pressure)
Low Pressure
Close Open
DOWN
UP