Removal And Replacement Of Water Regulating Valve (Water-Cooled Model) - Hoshizaki KMD-450MAH Service Manual

H. Removal and Replacement of Water Regulating Valve (water-cooled
model)
1. Always install a new drier every time the sealed refrigeration system is
opened.
2. 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.
3. 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).
1) Turn off the power supply.
2) Remove the panels.
3) Close the condenser water supply line shut-off valve. If connected to a closed loop
water supply, also close the condenser return outlet shut-off valve.
4) Open the condenser water supply line drain valve. If connected to a closed loop water
supply, also open the condenser return outlet drain valve.
5) Attach a compressed air or carbon dioxide supply to the condenser water supply line
drain valve.
6) Open the water regulating valve by using a screwdriver to pry up on the spring retainer
underneath the spring. While holding the valve open, blow out the condenser using the
compressed air or carbon dioxide supply until water stops coming out.
7) Recover the refrigerant and store it in an approved container.
8) Disconnect the capillary tube at the condenser outlet.
9) Disconnect the flare-connections of the valve.
10) Remove the screws and the valve from the bracket.
11) Install the new valve.
12) Remove the drier, then place the new drier in position.
13) Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG.
14) 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.
15) Evacuate the system, and charge it with refrigerant. See the nameplate for the required
refrigerant charge.
16) Connect the flare-connections.
17) Close the drain valve(s). Open the condenser water supply line shut-off valve. If
connected to a closed loop water supply, also open the condenser return outlet shut-off
valve.
18) Check for water leaks.
CAUTION
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