4
Evaporator type and size
If the evaporator has an even coating of frost, thermostat set
on 7, and system is not cycling, evaporator may be too small.
Either replace evaporator with a larger model, add insulation
to the bottom of the box to reduce volume, or re-locate
evaporator lower in box. The latter may cause the
temperature at top of the box to be above acceptable levels.
5
Excessive frost build-up
If an excessive layer of frost is allowed to build up on the
evaporator it will act as an insulator and adversely affect box
temperatures. Defrost system by interrupting power supply at
the breaker panel. Restore power when evaporator is free of
frost. Never use any hard or sharp implement in an attempt to
loosen the frost on the aluminum evaporator. Check that all
drains are blocked and there are no other openings or gaps
that will allow air to enter or leak from the box.
6
Incorrect refrigerant charge
If, after the compressor has been running for an appreciable
length of time, the evaporator surface does not have an even
coating of frost or it is only cold and sweating to the touch in
some areas and frosting in others, the system may be low on
refrigerant or overcharged. Call Veco NA for advice or go to
www.veco-na.com
"Technical Information".
7
Drain left unplugged
If your icebox is equipped with a drain in the bottom of the
box, this must be blocked off to prevent loss of cold air. The
drain should only be used if you revert to melting ice, or after
a major clean-up.
8
Tubing hole left unplugged
The hole that was drilled to allow the evaporator’s copper
tubes to pass through the box’s side during installation must
be sealed, as well as all other openings or gaps.
11:4
System runs, box temperature too low
Probable cause
Action
1
Thermostat setting
Rotate mechanical thermostat knob counter clockwise to a
lower number or adjust-set point on digital thermostat model.
2
Thermostat type
Check that you are using a refrigerator thermostat (white
housing) for a refrigerator application and with Bin (B) and
Horizontal (H) type evaporators in normal applications.
3
Faulty thermostat
If system is running continuously and box temperatures are
too low with thermostat set on the lowest number, first check
for correct thermostat connections at the controller, then
remove one connection. If compressor stops, turn off breaker,
replace connection, and then control system manually from
the breaker until the thermostat can be replaced.
