REPLACEMENT OF EXPANSION VALVE

Pump down the ice flaker and evacuate refrigerant from the liquid line. Carefully cut back the insulation on the suction line and remove the remote bulb. The bulb is secured to the suction line with two straps. Loosen and remove flare nuts on the expansion valve and remove the old valve ( or if soldered type valve, heat solder joint and remove valve). Install the new valve and tighten the flare nuts ( on soldered type valve follow common refrigeration practice while soldering valve so as to not damage valve during installation). Re-attach the bulb to the suction line, at approximately 5 O-Clock position. Secure the bulb using two straps. Re-insulate the suction line. Using a high quality vacuum pump, evacuate to remove any moisture that may have entered the system while the line was open to atmosphere.

ADJUSTMENT OF EXPANSION VALVE

If ice freezes on entire length of evaporator (top to bottom) but harvests only the upper portion with each revolution of the shaft and there are no bubbles in the sight glass, then the expansion valve must be adjusted. (Opened, to feed more refrigerant). On the other hand, frost on the compressor body indicates that the valve is overfeeding.

Remove the adjustment stem cover and turn the adjustment stem 1/8 to 1/4 turn at a time (clockwise to close the valve if it was overfeeding, counterclockwise to open the valve if the evaporator was not harvesting ice on its entire length.) Wait 10-15 minutes between each adjustment to allow the valve to stabilize. Repeat this step until ice is produced and harvested all the way down to the bottom of the evaporator. Note: Balanced Port Expansion Valves Are more sensitive than normal TXV's, so adjustment of the stem should be limited to between 1/16 to turn at a time.

TARGET SUPERHEAT SETTING

After visually verifying that the machine is freezing and harvesting ice over the entire evaporator, ( top to bottom on every rotation) the target superheat may be checked. The target superheat (checked at the suction line near the TXV bulb) should be approximately 5 F above saturated suction temperature.

Howe Corporation 1650 N Elston Ave, Chicago, IL. 60622 USA. Telephone 1-773-235-0200
Sales Fax 1-773-235-0269 Corporate Fax 1-773-235-1530