JOHNSON CONTROLS
136
FORM 155.30-ICOM2.EN.UL
ISSUE DATE: 12/21/2018
SECTION 7 – MAINTENANCE
DECRYSTALLIZATION METHOD
Even if the solution in the absorption chiller is crystal-
lized during operation, it can be melted if the crystal-
lization is not severe. Since it becomes more difficult
to melt the crystals as time passes, perform the decrys-
tallization operation immediately when crystallization
is detected. If the crystals cannot be melted by the fol-
lowing procedure, notify your local Johnson Controls
Service Center immediately.
Indications of Crystallization
• The refrigerating capacity goes down. The liq-
uid level in the absorber drops. Cavitation noise
comes out of one or more of the solution pumps.
• One of the following buttons is lit and the solution
circulation or solution spray pump trips:
•
Sol. Circu. P. Abnormal
•
Sol. Spray P Abnormal
• The solution level can be seen through the level
gauges on the generator.
• The liquid level in the absorber drops.
• The temperature of the solution returning from the
generator falls.
Decrystallization
1. Stop the chiller. If the solution pump tripped, reset
the thermal relay.
2. Disconnect the electrical wiring of the solution
pump.
3. Navigate to the Setting screen on the Control Pan-
el.
4. Press the Forced Dilution
ON
button.
NOTE: If the electrical wiring of the
solution pump is disconnected, only the
refrigerant pump will start.
5. Remove the cap of the refrigerant manual blow-
down valve V8.
NOTE: For the location of the refriger-
ant manual blow valve, see
6. Turn the spindle in the valve to the left with the
0.3 inch hexagon wrench.
NOTE: The refrigerant in the refrigerant
tank diverts into the absorber.
7. Watch the liquid level of the refrigerant tank.
8. Immediately after the refrigerant liquid level ap-
pears in the level gauge of the refrigerant tank,
close the refrigerant manual blow-down valve
(turn it to the right until it stops).
9. Press the Refrigerant Pump
Stop
button. The re-
frigerant pump stops.
10. Press the Forced Dilution
OFF
button.
11. Re-connect the electrical wiring of the solution
pump.
12. Press the Forced Dilution
ON
button. The solu-
tion pump starts.
13. Press the Control Valve Mode
Manual
button.
14. Set the valve position setting at 30 - 40%. See
Change Numeric Values on page 104
detailed information on how to change the set-
tings.
15. Watch the liquid level in the absorber.
16. When the liquid level in the absorber drops, press
the Forced Dilution
OFF
button.
17. Repeat steps 12 through 16 three - four times. If
the liquid level in the absorber does not go down,
the crystals have melted.
18. Let the solution pump operate independently for
about 30 minutes. Constantly observe the liquid
level in the absorber while the solution pump op-
erates.
19. After about 30 minutes, stop the solution pump.
20. Press the Refrigerant Pump
Auto
button.
21. Return the valve cap. There is an O-ring between
the cap and valve. When fitting the cap, make sure
that the O-ring is set normally.
