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E. Removal and Replacement of Evaporator
CAUTION
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) Raise the front panel, then move the power switch to the "OFF" position and unplug the
unit.
2) Remove the evaporator case cover and panels.
3) Recover the refrigerant and store it in an approved container.
4) Remove the insulation tubing, then disconnect the evaporator tubing. Elevate the
evaporator to avoid overheating of the evaporator housing. Lift out the evaporator.
Note: The pipes in the evaporator case are specially coated to resist corrosion. Use
sandpaper to remove the coating from the brazing connections before unbrazing.
5) Place the new evaporator in position.
6) Remove the drier, then place the new drier in position.
7) Braze all fittings while purging with nitrogen gas flowing at a pressure of 3 to 4 PSIG.
See "V.A.2. Brazing."
8) 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-134a as a mixture with
pressurized air for leak testing.
9) Evacuate the system, and charge it with refrigerant. See "V.A.3. Evacuation and
Recharge (R-134a)." See the nameplate for the required refrigerant charge.
10) Replace the removed parts in the reverse order of which they were removed.
11) Replace the evaporator case cover and panels in their correct positions.
12) Plug the unit back in. Move the power switch to the "ON" position.
13) Close the front panel.
