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SECTION 7 – MAINTENANCE
DECRYSTALLIZATION METHOD
Even if the solution in the absorption chiller is crystal-
lized during operation, it can be melted if the crystalli-
zation is not severe. Since it becomes more difficult to
melt the crystals as time passes, perform the following
operation immediately when crystallization is detect-
ed. If the crystals cannot be melted by the following
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 the solution pump.
• One of the following buttons is lit and the solution
pump trips:
• Sol. Circu. P. Abnormal
• Sol. Spray P Abnormal
• The solution level can be seen through the level
gauges on the high temperature generator level
gauges (G104).
• The liquid level in the absorber drops. The tem-
perature of the solution returning from the genera-
tor also 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.
Since the electrical wiring of the solution
pump is disconnected, only the refrigerant
pump starts.
5. Remove the cap of the refrigerant manual blow-
down valve.
138
For the location of the refrigerant manual
blow valve, see Figure 51 on page 133.
6. Turn the spindle in the valve to the left with the
0.3 inch hexagon wrench.
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 to 30-40%. For de-
tailed information on how to change the setting,
see Change Numeric Values on page 106 .
15. Observe 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.
FORM 155.31-ICOM2.EN.UL
ISSUE DATE: 12/21/2018
JOHNSON CONTROLS
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