Hoshizaki RF28A, Руководство по обслуживанию

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IV. Removal and Replacement of Components
IMPORTANT
1. The Polyol Ester (POE) oils used in all 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.
A. Service for Refrigerant Lines
1. Refrigerant Recovery
Using proper refrigerant practices recover the refrigerant from the access valve(s) and
store it in an approved container. Do not discharge the refrigerant into the atmosphere.
2. Evacuation and Recharge
1) Attach charging hose(s), a service manifold and a vacuum pump to the system.
Attachment of a charging hose to a high-side access valve is optional (if a high-side
valve is installed).
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 (if not already closed) on the service
manifold.
5) Disconnect the vacuum pump and attach a refrigerant service cylinder to the low-side
line. Remember to loosen the connection, and purge the air from the hose. See the
nameplate for the required refrigerant charge. Hoshizaki recommends that only virgin
refrigerant be used.
6) A liquid charge is required for charging an R-404A system and optional for charging an
R-134a system. Invert the service cylinder. Open the low-side, service manifold valve.
IMPORTANT
In order to prevent compressor damage, use caution in charging large
quantities of liquid into the low side.
7) Allow the system to charge with liquid until the pressures balance.
8) Close the refrigerant access valve(s) and disconnect the hose(s) and service manifold.
9) Cap the access valve(s) to prevent a possible leak.