Koolaire KY0275W Technician's Handbook page 63

Extremely Thin at Evaporator Outlet
There is no ice, or a considerable lack of ice formation on
the outlet of the evaporator.
Examples: No ice at all at the outlet of the evaporator, but
ice forms at the inlet half of the evaporator. Or, the ice at
the outlet of the evaporator reaches the correct thickness,
but the outlet of the evaporator already has 1/2" to 1" of
ice formation.
Possible cause: Water loss, low on refrigerant, starving
TXV, hot water supply, faulty float valve, etc.
Extremely Thin at Evaporator Inlet
There is no ice, or a considerable lack of ice formation at
the inlet of the evaporator. Examples: The ice at the outlet
of the evaporator reaches the correct thickness, but there
is no ice formation at all at the inlet of the evaporator.
Possible cause: Insufficient water flow, flooding TXV, etc.
Spotty Ice Formation
There are small sections on the evaporator where there is
no ice formation. This could be a single corner, or a single
spot in the middle of the evaporator. This is generally
caused by loss of heat transfer from the tubing on the
backside of the evaporator.
No Ice Formation
The ice machine operates for an extended period, but
there is no ice formation at all on the evaporator.
Possible cause: Water float valve, water pump, starving
expansion valve, low refrigerant charge, compressor, etc.
Part Number STH047 5/16 63