Hussmann KRACK MK Series Installation And Operation Manual Download

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MK/MV – Medium Profile Series Unit Coolers (E206993_M)

Q.1.61 November 2018

Page 7

• Check wiring to the EEV terminal on the KE2 Evap OEM board. Refer below for

proper wiring of the KE2-RSV EEV and other common EEV wiring.

OTOR

BLUE

ORANGE

YELLOW

RED

BLACK

OTOR

RED

GREEN

WHITE

BLACK

EEV

EMPTY

RSV

• The bare stranded wire of the EEV cable should be inserted so that the wire is di-

rectly 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 from

entire length of the lead wire, through the windings of the EEV and back to the

other lead. Remove the EEV leads from the terminals, and for KE2 RSV measure:

Check resistance across EEV leads:

Wire Colors

RSV-100 to 320 RSV-400 to 550

Blue - Orange

36 ohms

32 ohms

Blue – Yellow

36 ohms

32 ohms

Blue – Red

36 ohms 32 ohms

Blue – Black

36 ohms

32 ohms

Also check resistance between the windings:

Wire Colors

RSV-100 to 320 RSV-400 to 550

Orange – Yellow

96 ohms

65 ohms

Orange – Red

96 ohms

65 ohms

Orange – Black

96 ohms

65 ohms

Yellow – Red

96 ohms

65 ohms

Yellow – Black

96 ohms

65 ohms

Red – Black

96 ohms

65 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 wiring 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.

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 install-

ing contractor adjust the low pressure cut-in and cut-out to recommended settings

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 inter-

mittent, 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 speci

cation 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