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L-2091 Operation
Possible Reason/Correction:
1. Low voltage to unit.
Check for low voltage to unit.
2. Poor condenser cooling.
Check fan and coil for proper airfl ow. Ventilate area
if temper
ature is above 100°F/38°C. Check seaw
ater
system.
Fault: Compressor and fan (or pump) running, but box
does not cool.
Possible Reason/Correction:
1. Poor condenser cooling.
Check fan and coil for proper airfl ow. Ventilate area
if temper
ature is above 100°F/38°C. Check seaw
ater
system.
2. Constant Pressure Valve (CPV) not set correctly
Connect R-134a gauge set and check low side pres-
sure. See section “Setting the CPV”.
3. Thermostatic Expansion Valve (TXV) not set cor-
rectly.
Adjust superheat following instructions in Section
“Adjusting the
TXV”.
4. Low refrigerant charge.
Check for a refrigerant leak and repair it. Evacuate
unit and recharge with the correct amount of R -134a.
5. TXV or CPV Mechanical failure.
Have technician diagnose and replace.
Fault: Systems starts to cool, but stops as plates freeze.
Possible Reason/Correction:
1. Moisture in system.
Replace liquid line drier. Evacuate unit and recharge
with R-134a.
Fault: Compressor operates, but seawater pump doesn’t
Possible Reason/Correction:
1. Pump relay failure.
Turn on or reset pump breaker. Check pump relay
and pump rela
y trigger.
Fault: Unit Does Not Run
Possible Reason/Correction:
1. Power is OFF at panel.
Turn Power ON, check to see if thermostat display
comes on.
2. Thermostat is set incorrectly or may be faulty.
If the display is on, check for proper thermostat set-
ting. Ensure the correct voltage at thermostat.
If the thermostat is showing a fault code, ref
er to
Digital
Thermostat Displa
y Error Messages section
belo
w.
If thermostat still does not send v
oltage to the
condensing unit or if fault code is present, replace
ther
mostat.
3. No voltage is getting to thermostat, but panel
switch is on.
Check for loose or missing wiring connections. Make
sure that there is not another in-line cut-off switch.
4. Start component failure.
Check components for failure. Replace if necessary.
5. Compressor failure.
Check compressor windings.
Check conductance from windings to ground.
If compressor windings are good, b
ut unit will not
star
t, try adding a start booster.
Fault: Insuffi cient Cooling of Box
Possible Reason/Correction:
1. Excessive frost is in box.
Turn unit OFF, and defrost according to the “User
Maintenance”
section.
2. Improperly set thermostat.
Review Operation Section, or Figure 5, to set ther-
mostat correctly.
3. Excessive open-box time.
Unit requires time to catch up after being opened.
Decide what you are going to get bef
ore opening the
bo
x, then conduct removal quickly to prevent warm
air infi ltration.
4. Recent addition of large quantities of warm
items.
Unit will slowly pull the heat out of the warm items,
allow for recovery time.
5. Poor seals, no drain plug.
Poor seals allow ambient air to infi ltrate box, bringing
moisture with it.
Replace seals if necessary.
Leaving the drain plug out during regular oper
ation
allo
ws outside air, possibly ev
en hazardous or bilge
gases
, to enter box.
6. Improperly set Constant Pressure Valve (CPV).
Have a certifi ed technician check the suction pres-
sure, and set the valve according to the
“Recharging
the System”
section.
7. Improperly set Thermostatic Expansion
Valve (TXV).
Have a certifi ed technician check the suction pres-
sure, and set the valve according to the
“Recharging
the System”
section.
8. Low refrigerant charge.
Have a certifi ed technician check for this problem.
If the technician fi nds a lo
w charge condition, he/she
should chec
k for leaks using the UV dy
e system that
is b
uilt into the KRA Refrigeration System or by
using an electronic leak detector.
Unit should be recharged to rated system capacity.
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