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KE2 EvapOEM
Alarm Troubleshooting Guide
HSH / LSH Corrective Action - Continued
Check wiring to the EEV terminal on the KE2 Evap OEM board. Refer below for prop-
er wiring of the KE2-RSV EEV and other common EEV wiring.
RSV
• The bare stranded wire of the EEV cable should be inserted so that the wire is
directly touching the gate of the connector. If the gate is contacting the insulation
of the wire, it will not allow the controller to correctly operate the valve.
• If wires have been extended, check that colors have not been swapped.
• Measure resistance across the EEV leads. This will measure the resistance for
the entire length of the lead wire, through the windings of the EEV and back to the
other lead.
Check resistance across RSV leads:
Wire Colors
RSV-100 to 320 RSV-400 to 550
Blue – Orange
36 or 46 ohms
Blue – Yellow
36 or 46 ohms
Blue – Red
36 or 46 ohms
Blue – Black
36 or 46 ohms
For Sporlan SER-AA to L, measure:
Wire Colors
Black – White
100 ohms
Red – Green
100 ohms
Black – Green
Open
Red – White
Open
All values should be within 10% of stated values, otherwise indicating a wir-
ing issue. If absolutely sure of no wiring issue, the external coil may need to be
replaced. For valves with internal windings, the valve may need to be replaced.
• If electrical diagnosis reveals no issues, and no system issues are present, there
may be debris in the valve port. The valve can be driven open/closed several times
through the manual control, while also lightly tapping the valve in an attempt
to dislodge any debris. If valve has a strainer, strainer may need to be cleaned.
21214V3.0
EEV
32 ohms
32 ohms
32 ohms
32 ohms
HSH / LSH Corrective Action - Continued
Low Superheat Alarm Only
The Low Superheat Alarm is most commonly caused by the compressor failing to
start/ compressor not running. There is a common misconception in the industry
that the low pressure switch cut-in and cut-out pressure control on the condensing
unit is set correctly for the application from the factory.
The equipment manufacturers' installation instructions recommend that the in-
stalling contractor adjust the low pressure cut-in and cut-out to recommended set-
tings for the application. The low pressure cut-in and cut-out set point should be
set to either the ambient or space temperature, whichever is lower.
When the controller calls for refrigeration, if suction pressure is not able to rise to
the cut-in pressure before the EEV closes due to low superheat, the system will not
start, and a Low Superheat Alarm triggered.
Our technical support team typically sees an increase of these alarms in the fall
when the ambient temperatures begins to decrease. If the low superheat alarm is
intermittent, this is the most likely source of the alarm. Check the following:
• Low Pressure Control Pressure Switch. Reduce the cut-out pressure to meet the
equipment manufacturer's specification for the coldest ambient or box tempera-
ture, whichever is lower.
• Measure continuity across the low pressure control, if it indicates a closed cir-
cuit, next check the compressor start components and continue diagnosis at the
condensing unit.
• Verify all fans are moving. Check if there is a mechanical service switch for the
fans in the space being used inappropriately. If only one fan is not moving, verify
whether the fan is operational. Replace the motor if necessary.
• Check fan motor rotational direction and fan blade pitch to ensure air is flow-
ing in the proper direction.
• Check for diminished load due to low air movement across the coil. This can
be caused by excessive frost build-up on the coil on the air entering and/or air exit-
ing sides of the coil. The fans should be turned off while checking for frost buildup
to allow a clear view of the coil. Product that is stacked too close to the coil and
impedes airflow through the coil can also be a source of diminished load.
• Check EEV and EEV wiring/cables – Please see previous steps.
© Copyright 2023 KE2 Therm Solutions, Inc., Washington, Missouri 63090
Q.1.61 January 2023
Page 9
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