Koolaire STH045 8/15 Technician's Handbook page 60

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, faulty water inlet 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.
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 inlet valve, water pump,
starving expansion valve, low refrigerant charge,
compressor, etc.
60 Part Number STH045 8/15