Hoshizaki KM-320MAH - Manual (Page 34)

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V. Removal and Replacement of Components
IMPORTANT
Ensure all components, fasteners and thumbscrews are securely in place after
the equipment is serviced.
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 drier every time the sealed refrigeration system is
opened.
3. Do not leave the system open for longer than 5 minutes when replacing or
servicing parts.
A. Service for Refrigerant Lines
1. 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.
2. 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 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.
6) A liquid charge is recommended for charging an R-404A system. Invert the service
cylinder. Open the high-side, service manifold valve.
7) Allow the system to charge with liquid until the pressures balance.