JOHNSON CONTROLS
122
FORM 155.33-ICOM2.EN.GB
ISSUE DATE: 12/4/2017
SECTION 8 – TROUBLESHOOTING
TABLE 27 -
REFRIGERANT OVERCOOLED
ITEM
CAUSE
COUNTERMEASURE
1
Chilled / hot water flow
rate drops or changes
suddenly.
See if the chilled / hot water flow rate changes quickly (particularly in the case
of variable flow rate specification). If it changes suddenly, apply a limit of the
change rate to the chilled / hot water flow control or take another measure.
2
Cooling water temperature
at inlet changes suddenly.
See if the cooling water temperature at inlet changes quickly (by checking start
and stop of the fan). If the chiller-heater refrigerant temperature is low, the
chiller-heater stops immediately but does not perform the dilution operation.
If left as it is, the solution may crystallize in 4-5 hours. To prevent this, dilute
the solution. See
Manual Refrigerant Blowdown and Dilution Method on page
.
3
Load lowers quickly.
See if the load changes unexpectedly.
4
Refrigerant is dirty
(contains solution).
See if the refrigerant refining operation has been performed periodically. For
the refrigerant refining method, see
Refrigerant Refining Method on page
.
5
Heat exchange tube is
dirty (Chilled / hot water).
Contact your local Johnson Controls Service Office.
6
Temperature controller or
safety switch is broken.
If the chiller-heater / hot water flow stops, the chiller-
heater stops immediately without diluting the solution.
If the absorption chiller-heater is left as it is, the solu-
tion in it may be crystallized in 4 to 5 hours. To prevent
this, dilute the solution. See
down and Dilution Method on page 97
TABLE 28 -
CHILLED / HOT WATER SUSPENSION
ITEM
CAUSE
COUNTERMEASURE
1
Chilled / hot water pump
has a problem.
Check the chilled / hot water pump for a problem.
2
Chilled / hot water flow
rate is low.
• Check to see if the chilled / hot water flow-rate is below the setpoint of the
water suspension switch. If it is low, check the flow controller.
• Check the strainer for clogging.
• Check the opening ratio of the flow control valve.
3
Pressure transfer pipe of
water suspension switch
is clogged.
Contact your local Johnson Controls Service Office.
4
Water suspension switch
is broken.
If the chiller-heater has a pump problem, it stops im-
mediately without performing the dilution operation. If
left as it is, the solution in it may be crystallized in 4
to 5 hours. To prevent this, contact your local Johnson
Controls Service Office immediately.
TABLE 29 -
PUMPS OVERLOADED OR OVERHEATED
ITEM
CAUSE
COUNTERMEASURE
1
Bearings of the pump are worn or clogged.
Contact your local Johnson Controls Service
Office.
2
Pump is damaged by cavitation caused by low liquid level.
3
Thermal switch is not set properly.
4
Internal cycle control valve is not set properly.
5
Filter in the pump is clogged.
6
Solution is crystallized.
7
Circuit breaker has tripped.
