Hoshizaki KM-420MWJ Service Manual page 67

• Always install a new drier every time the sealed refrigeration system is opened.
• Do not replace the drier until after all other repair or replacement has been made.
Install the new drier with the arrow on the drier in the direction of the refrigerant
flow.
• When brazing, protect the drier by using a wet cloth to prevent the drier from
overheating. Do not allow the drier to exceed 250°F (121°C).
2) Use an electronic leak detector or soap bubbles to check for leaks. Add a trace of
refrigerant to the system (if using an electronic leak detector), and then raise the
pressure using nitrogen gas (140 PSIG). Do not use R-404A as a mixture with
pressurized air for leak testing.
3. Evacuation and Recharge (R-404A)
The condensing unit and icemaker are provided with refrigerant shutoff valves.
Evacuation and recharge via the condensing unit's refrigerant shutoff valves is
recommended.
1) Attach a vacuum pump to the system. Be sure to connect the charging hoses to both
high and low-side refrigerant shutoff valves.
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. Open the gauge manifold valves, then open the high and
low-side refrigerant shutoff valves. Never allow the oil in the vacuum pump to flow
backwards.
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 gauge manifold.
5) Disconnect the gauge manifold hose from the vacuum pump and attach it to a
refrigerant service cylinder. Remember to loosen the connection and purge the air from
the hose. For the required refrigerant charge, see the nameplate on the condensing unit
or the rating label inside the icemaker. Hoshizaki recommends only virgin refrigerant or
reclaimed refrigerant which meets ARI Standard 700 (latest edition) be used.
NOTICE
IMPORTANT
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