Q.1.61 January 2023
Page 7
KE2 Evap
OEM
Alarm Troubleshooting Guide
© Copyright 2023 KE2 Therm Solutions, Inc., Washington, Missouri 63090
21214V3.0
Troubleshooting Tables
Alarm & Alarm Name
Description
Variables & Setpoints Corrective Action
Basic
Display
Combo
Display
Web-
pages
EdF
EdF
EXCESS
DEFROST
Excess
Defrost
Alarm
Yellow LED is illumi-
nated. Controller will
attempt to continue
to operate system
while this alarm is
present.
Time between
defrosts too short in
demand defrost.
Variables
CLt - Coil Temp
DEr - Defrost Relay
Setpoints
dtY - Defrost Type
ind - Initiate Defrost
Mode
dtP - Defrost Term Temp
Excess Defrost Alarm and Defrost Termination on Time Alarm are closely linked;
both indicate issues with the defrost process/defrost heat. Excess defrost alarm only
occurs when using defrost based on evaporator efficiency (demand).
Air/ Electric / Hot Gas Defrost - Check solenoid valve. While the controller is in
refrigeration or satisfied on temperature, initiate a defrost from the Basic Display by
pressing and holding the
and
until ddF (defrost delay fan) or dEF appears.
The solenoid valve should close and the flow of liquid refrigerant to the evaporator
should be stopped for the entire defrost.
Note: For electric and hot gas defrost, the controller should run fans only for several
minutes while the system pumps down in ddF (defrost delay Fan) mode. In ddF,
solenoid valve and heaters should be off. The display will change to dEF (defrost) after
the fan operation is complete. Fans should turn off, solenoid valve should remain off,
and all heaters should turn on.
Electric Defrost - Verify that the heaters are working properly. Measure amperage of
the heaters while heaters are energized and check that it matches the nameplate of
the evaporator. If less than the nameplate, check for damaged heaters and any cut,
burned, chaffed or disconnected wires in the heater circuit. Repair damage and check
for proper defrost operation.
Note: Toward the end of the defrost cycle, the controller periodically turns heaters off
to reduce steaming and overall heat of defrost.
Air/ Electric / Hot Gas Defrost - Verify coil sensor location. An excessive number
of defrosts is often due to coil sensor location. The coil sensor, or sensors, serve as
defrost termination sensors. If in an improper location (such as close to a heater), or
if a coil sensor has been pulled out, defrost will terminate too soon or will take too
long to terminate. The controller will respond by initiating another defrost shortly
after the irregular defrost, and the cycle will continue until the Excess Defrost Alarm
is triggered. Relocate the coil sensor to where frost has built up the heaviest on the
coil and initiate a defrost. Check to make sure the defrost terminates in a reasonable
amount of time (less than 30-35 minutes for air defrost, less than 18-22 minutes for
electric defrost) and the coil is completely clear of frost. If there is any frost remaining
on the coil after the defrost, relocate a coil sensor to that location. The proper location
for the coil sensor is always the last place frost disappears.
Air/ Electric / Hot Gas Defrost - Verify door has not been left open for an extended
period. Add door switch (PN 20543) to reduce excess frost caused by door openings.
Air/ Electric – Cold air from an evaporator in refrigeration in the same space may
prevent a defrosting coil from reaching termination temperature within a reasonable
amount of time. Bonding and synchronizing defrost on the evaporators allows the
evaporators to defrost more quickly. See Q.1.45-A Multi Evap Applications for more
information on bonding.
Air Defrost - The KE2 Evap OEM keeps the room temperature much tighter than is
typically seen in the industry. The KE2 Evap OEM’s default air temperature differential
is 1.0°F, while the system is still protected from short cycling by minimum off and
minimum run times if temperature fluctuation is larger than normal. If the room
temperature setpoint on the KE2 Evap OEM is set to the same temperature cut-out
as traditional mechanical controls where differentials of 4.0°F or 5.0°F are common,
it will result in a much colder room temperature on average. Consider this when
setting the room temperature setpoint. If receiving Defrost Termination on Time or
Excess Defrost Alarm with air defrost, the room air heat alone may not be sufficient to
complete the air defrost. The room temperature setpoint should be raised, or electric
heat added to the evaporator. Alternatively, dtP (defrost term temp) can be lowered
to one degree above rTP (room temp), however, the coil sensor MUST be in the spot
on the coil where frost disappears last during defrost to ensure a completely clean coil
after every defrost. Otherwise, set ind (initiate defrost mode) to SCH (schedule), and
set dPd (defrost per day) and dtL (defrost time length) to the number of times per
day and length of defrost needed to completely clear the coil of frost. If the maximum
defrost time is still not sufficient to clear the coil of frost, the Defrost Termination on
Time Alarm will continue to trigger.
Return Defrost Mode to Demand after resolving the issue.
dtt
dtt
DEFR TERM
ON TIME
Defr
Term
on Time
Alarm
Yellow LED is illumi-
nated. Controller will
attempt to continue
to operate system
while this alarm is
present.
Defrost terminated
on time instead of
temperature for two
consecutive defrosts.