Ice-O-Matic ICE0250 Series - Manual (Page 57)

ICE Series Refrigeration System
Page E4
Thermostatic Expansion Valve (Continued)
A dual evaporator machine will have one TXV for each evaporator. If one TXV sticks open and the
other is operating normally, the suction pressure will be higher than normal and both evaporators
will build thick ice. It is recommended that both valves be replace if one sticks open.
If one TXV sticks closed and one is operating normally, the suction pressure will be normal or low
but the evaporator with the defective valve will be starved (thick ice at the bottom and thin ice at
the top).
Evaporator
As water is circulated over the front of the evaporator, liquid refrigerant is circulated through the
tubing attached to the back of the evaporator. As the liquid refrigerant in the tubing vaporizes, it
absorbs heat from the water causing the water to freeze. The evaporator should be completely
flooded throughout most of the freeze cycle. A flooded evaporator will build ice evenly across the
evaporator. A starved evaporator will have uneven ice formation. Most problems with ice
formation or harvesting are not related to a defective evaporator, use the Troubleshooting Trees in
section C for additional help.
Refrigerant enters the evaporator through the bottom tube and exits through the top tube. On
models ICE800, 1000, 1800 and 2100 the refrigerant line at the TXV outlet splits into two feeder
tubes. This split occurs at the distributor, which is a fitting that is soldered to the TXV. One feeder
tube from the distributor feeds the top of the evaporator; the other tube feeds the bottom of the
evaporator. The evaporator tubes run parallel, in opposite directions, along the back of the
evaporator creating a dual pass.
If the evaporator is flooded but not building ice evenly, it is possible the evaporator has coil
separation. Evaporator coil separation is the separation of the refrigerant tubing from the back of
the evaporator plate. This is very rare but occasionally occurs.
To confirm coil separation, remove and check the back of the evaporator. If the coil is separated,
the evaporator must be replaced. If the outlet(s) of the evaporator is not frosted, the problem is not
with coil separation (Refer to the troubleshooting trees, section C).
In
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