Removal And Replacement Of Expansion Valve - Hoshizaki KM-280MAF-E Service Manual

5. REMOVAL AND REPLACEMENT OF EXPANSION VALVE

Sometimes moisture in the refrigerant circuit exceeds the Drier capacity and
freezes up at the Expansion Valve. Always install a new Drier every time the
sealed refrigeration system is opened. Do not replace the Drier until after all
other repairs or replacements have been made.
1) Turn off the power supply. Unplug the icemaker.
2) Remove the panels.
3) Recover the refrigerant and store it in an approved container. (See "1. [a] REFRIGER-
ANT RECOVERY".)
4) Remove the insulation and the Expansion Valve Bulb on the suction line.
5) Remove the Expansion Valve Cover, and disconnect the Expansion Valve using
brazing equipment. Protect adjacent components from excessive heat using damp
cloths or similar.
6) Braze the new Expansion Valve, with nitrogen gas flowing at the pressure of 0.2 - 0.3
BAR.
1. Do not heat the wall. Place a steel barrier for protection.
2. Always protect the valve body by using a damp cloth to prevent the valve
from overheating. Do not braze with the valve body exceeding 250°F
(120°C.
7) Install the new Drier.
8) Check for leaks using nitrogen gas (10 BAR) and soap bubbles.
9) Evacuate the system, and charge it with refrigerant. See the Nameplate for the re-
quired refrigerant charge. (See "1. [b] EVACUATION AND RECHARGE".)
10) Attach the Bulb to the suction line in position. Be sure to secure it with clamps and
to insulate it.
11) Place the new set of Expansion Valve Covers in position.
12) Refit the panels in their correct positions.
13) Plug in the icemaker. Turn on the power supply.
IMPORTANT
WARNING
65