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L-2091 Operation
Refrigeration Systems • Operation
This section of the manual refers to essential safe operation for
all KRA refrigeration systems. For any operational problems call
your dealer, or call our service department at 804-746-1313.
KRA Refrigeration Start-Up Check List
A. Before you start the system:
1. Check that all refrigerant connections are tightened to
10-12 ft. lbs.
2. Check to make sure that all refrigerant lines are
secured so as not to rub against other objects during
operation.
3. Ensure all suction line connections are insulated to
prevent ice build-up.
4. Confi rm that electrical connections are correct, and are
tight.
5. Make sure that thermostat is mounted securely, and
wires are routed safely.
6. Make sure that unit is securely mounted.
7. Check to make sure that airfl ow into and out of the unit
is not obstructed.
8. Check water connections (if used) to make sure that
they have correct fl ow direction, and that connections
are tight.
9. Confi rm that thermostat sensing bulb is mounted in the
correct area of the box, and that it is secure.
10. Make sure that the thermostatic expansion valve bulb is
mounted correctly and securely.
11. Make sure that frequently accessed parts are easily
accessible, i.e. constant pressure valve, TX valve,
thermostat, quick connects, condensing unit.
12. Check the seals on the box lid to make sure that they
have good contact to the box top.
B) Starting the system:
1. Turn on the designated circuit breaker on the boat’s
electrical panel.
2. For units with a water-cooled condenser, fi rst open the
seacock. If pump is shared with another system, ensure
that pump circuit breaker is on.
3. Set thermostat to desired temperature.
4. Watch the sight glass to make sure that refrigerant is
fl owing.
5. Check the sight glass to make sure the element inside
is green (no moisture contamination.)
6. Confi rm that water (if used) is fl owing out of overboard
(see note below).
7. Confi rm that condenser fan is running.
8. Visually confi rm frost at the metering device valve after
a few minutes of running.
9. Watch for temperature decrease inside the box.
C. Systems with two evaporators and one condensing unit:
1. Check all wiring to confi rm that both thermostats run
through a condensing unit relay (i.e., RR3X-2(C)) to
bring the condensing unit and pump (optional) on.
2. To check pressures and refrigerant charge, if neces-
sary, follow these instructions:
a. Turn on only one box. Make sure that box works
correctly. Wait approx. 10 min.
b. Turn off the fi rst box, turn on the other one. Use the
same procedure.
c. Turn both boxes on, and check sight glass. It should
be at least 3/4 full. If not, add refrigerant.
3. Follow procedures for “Starting the system” in section B.
Note:
The seawater pump will cycle automatically whenever the
compressor is running. Regularly check for seawater fl ow by
observing the overboard discharge when the system is fi rst
turned on. If you do not observe steady water fl ow, turn off
the system and check for obstructions in the seawater cooling
system.
Thermostat Operation
A thermostat controls the condensing unit. It monitors box
temperature and turns on the compressor when the box
temperature rises above the setpoint. See Figure 5.
Standard thermostats have a digital display that normally
shows the approximate box temperature. To change the set-
tings of the thermostat, follow these directions:
• Press the SET key and toggle the UP and DOWN arrow
keys. The fi rst mode is the Fahrenheit/Celsius mode. Toggle
the arrow keys to the desired setpoint.
• The second mode, which is accessed by pressing the SET
key again, is the SETPOINT, S1. Change by using the arrow
keys.
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