©Copyright 2015 KE2 Therm Solutions, Inc., Washington, Missouri 63090
N.1.1 July 2015
Page 5
KE2 EvaporatorEfciency
Installation Instructions
Important: Verify all heating elements are working properly.
Due to the many factors inuencing the evaporator perfor-
mance, it is impossible for KE2 Therm to provide the proper loca-
tion of every installation. However, the coil sensor is an integral
part of the control algorithm used to determine coil eciency
to initiate, as well as, terminate defrosts. The coldest point in
the coil can be identied from existing system knowledge or by
monitoring the normal operation.
Controller Power - The high voltage wiring is protected by a
metal shield fastened to the back side of the controller. The
shield should be removed to gain access to the wiring connec-
tions, making note of the location of the fasteners. The screws in
the upper corners are coarse thread screws, while the screw in
the middle is a 4-40 machine screw.
The controller accepts either 120V or 208/240V incoming power.
The controller includes metal oxide varistors (MOVs), providing
protection from voltage spikes. MOVs use the same technology
commonly applied to protect consumer electronics (surge pro-
tectors). They function by ltering out voltages high enough
to damage the board. When the voltage exceeds the allowed
amount, the MOVs short to ground, protecting the circuitry. For
additional protection, the board has a replaceable 1/2 or 500mA
fuse in line. The grey plug is accessible without removing the
metal shield in the fuse holder. Depress slightly and turn 1/4
turn counterclockwise to remove. Replace by depressing slight-
ly and turning 1/4 turn clockwise. Do not overtighten.
The board uses a pluggable screw terminal connector forn in-
coming power. The terminal is in the top right corner of the
controller, when the terminals are facing the user. See Figure 6.
Fan and Defrost Relays - There are 2 larger relays on the con-
troller with spade connectors. These are used for the evaporator
fans and defrost heaters. Due to the spacing of the enclosure
the spades require a 90 degree terminal. KE2 Therm has includ-
ed (4) spade connectors to assist in wiring the relays.
Evaporator Fan Relay - The fan relay is rated 10A inductive
at 240V. One leg of the incoming power (L1) for the fans con-
nects to the COM terminal of the fan relay, the upper of the two
larger relays. The remaining leg, (L2) connects to one lead of
the fan. The remaining fan lead should be connected to the NO
(Normally Open) terminal on the fan relay. See Figure 8.
Defrost Heater Relay - The heater relay is rated 20A resistive at
240V. One leg of the incoming power (L1) for the heaters con-
nects to the COM terminal of the heater relay, the lower of the
two larger relays. The remaining leg, (L2) connects to one lead
of the heater. The remaining heater lead connects to the NO
(Normally Open) terminal on the heater relay.
Compressor/Liquid Line Solenoid Relay - The compressor re-
lay is rated at 3A inductive at 240V. This relay uses the 3-position
pluggable screw terminal to make the connection to the board.
The relay is not intended to control the compressor directly. It
is designed to be used to control the liquid line solenoid or as
a pilot to the compressor contactor. One leg of the incoming
power supply (L1) should be connected to COM terminal of the
compressor relay, the upper of the two smaller relays. The re-
maining leg, (L2), should be connected to one lead on the so-
lenoid/compressor contactor. The remaining lead, should be
connected to the normally open (NO) position on the terminal.
Auxiliary Relay - The auxiliary relay is rated at 3A inductive at
240V. This relay uses the 3-position pluggable screw terminal
to make the connection to the board. The relay may be con-
nected to a variety of devices. One leg of the incoming power
supply (L1) should be connected to COM terminal of the auxil-
iary relay, the lower of the two smaller relays. The remaining leg,
(L2), should be attached to one lead on the connected device.
The remaining alarm lead, should be connected to the normally
open (NO) position on the terminal.
After all high voltage wiring is completed, the metal shield
must be replaced and screws tightened.
Additional Inputs
T1 Suction Temperature Sensor (Auxiliary) - The suction tem-
perature sensor is required when applying the controller with
an electronic expansion valve. The sensor’s proximity to the
evaporator outlet diers slightly for electronically controlled
valves from the placement of a TEV bulb. Due to the more re-
ned control from an electronically controlled valve, the sen-
sor must be placed as close to the outlet of the coil as feasible.
Although the distance from the outlet is dierent, the nature
of the refrigerant’s ow through the tube remains unchanged,
thus the orientation of the sensor remains at the 4 or 8 o’clock
position. The sensor should be secured to the suction line using
the included wire ties designed for low ambient operation. In
addition to being congured as a suction sensor, the T1 input
may also be congured like the auxiliary sensor.
Pressure Transducer - In addition to the suction temperature
sensor, a pressure transducer is required for superheat measure-
ment when applying KE2 Therm’s Hybrid Stepper Valve (HSV) or
Refrigeration Stepper Valve (RSV). Mount the pressure tap on
the top of a horizontal section of tube, near the suction sensor,
approx. 3 inches downstream of the temperature sensor.
T4 Auxiliary Temperature Sensor -The auxiliary temperature
sensor provides exibility and may be used for any purpose de-
sired by the user. The placement of the sensor is dependent on
the requirements of the user’s intended application. The Auxil-
iary Temperature sensor must be supplied by KE2 Therm.
Digital Inputs - The controller includes (3) digital inputs. See
Table 3 for conguration options.
Mounting the Controller
Once the wiring has been run to the controller location, the con-
troller can be connected. When installing the KE2 Evaporator
Eciency, the (4) screws supplied in the kit may be preinstalled
in the mounting surface. The controller has keyholes in each
mounting tab allowing the controller to install over the screws.
