[B] Refrigerant Recovery; [C] Evacuation And Recharge - Hoshizaki FM-150KE(-N) Service Manual

7) Evacuation, Vacuum Pump and Refrigerant Charge [R404A/R134A]
Never allow the oil in the vacuum pump to flow backward. The vacuum level and vacuum
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
R404A/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 electronic detector. Do not use air or oxygen instead of
nitrogen for this purpose, or rise in pressure as well as in temperature may cause
R404A/R134A to suddenly react with oxygen and explode. Be sure to use nitrogen to
prevent explosion.

[b] REFRIGERANT RECOVERY

The refrigerant must be recovered if required by an applicable law. A low-side access valve
is provided in the unit (modular type only). Recover the refrigerant from the access valve,
and store it in a proper container. Do not discharge the refrigerant into the atmosphere.
When replacing the drier, take the opportunity to also fit a low-side access valve
(self-contained type only) and a high-side access valve for ease of charging liquid
refrigerant.

[c] EVACUATION AND RECHARGE

R134a models
1) Attach a charging hose of a gauge manifold to a vacuum pump and the low-side access
valve (to be fitted by service personnel for self-contained type).
2) Open the low-side valve on the gauge manifold, and turn on the vacuum pump.
3) Allow the vacuum pump to pull down to a 760 mmHg vacuum. Evacuating period
depends on the pump capacity.
4) Close the low-side valve on the gauge manifold.
5) Disconnect the vacuum pump, and attach a refrigerant charging cylinder to accurately
weigh in the liquid charge. Remember to purge any air from the charging hose. See the
nameplate for the required refrigerant charge.
6) Open the low-side valve on the gauge manifold and the valve on the charging cylinder.
7) When no more refrigerant is drawn in, turn on the icemaker. When the required amount
of refrigerant has been charged, close the valve on the charging cylinder and turn off the
icemaker.
8) Close the low-side valve on the gauge manifold.
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