Hoshizaki F-450MAH - Manual (Page 35)

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IMPORTANT
1. The Polyol Ester (POE) oils used in R-404A units can absorb moisture
quickly. Therefore it is important to prevent moisture from entering the
system when replacing or servicing parts.
2. Always install a new filter drier every time the sealed refrigeration system
is opened.
3. Do not leave the system open for longer than 15 minutes when replacing
or servicing parts.
V. Removal and Replacement of Components
1. Service for Refrigerant Lines
[a] Refrigerant Recovery
The icemaker unit is provided with two refrigerant access valves - one on the low-side and
one on the high-side line. Using proper refrigerant practices recover the refrigerant from the
access valves and store it in an approved container. Do not discharge the refrigerant into
the atmosphere.
[b] Evacuation and Recharge [R-404A]
1) Attach charging hoses, a service manifold and a vacuum pump to the system. Be sure
to connect charging hoses to both high-side and low-side access valves.
IMPORTANT
The vacuum level and vacuum pump may be the same as those for current
refrigerants. However, the rubber hose and gauge manifold to be used for
evacuation and refrigerant charge should be exclusively for POE oils.
2) Turn on the vacuum pump. Never allow the oil in the vacuum pump to flow backward.
3) Allow the vacuum pump to pull down to a 29.9" Hg vacuum. Evacuating period
depends on pump capacity.
4) Close the low-side valve and high-side valve on the service manifold.
5) Disconnect the vacuum pump, and attach a refrigerant service cylinder to the high-side
line. Remember to loosen the connection, and purge the air from the hose. See the
nameplate for the required refrigerant charge. Hoshizaki recommends only virgin
refrigerant or reclaimed refrigerant which meets ARI Standard No. 700-88 be used.