Table 37 - Chilled Water Suspension; Table 38 - Pumps Overloaded Or Overheated; Table 39 - Chilled Water Time Out Or Cooling Water Time Out - York YHAU-CW Manual

FORM 155.31-ICOM2.EN.UL
ISSUE DATE: 12/21/2018
In the case of chilled water suspension, the absorption
chiller does not perform the dilution operation. It stops
immediately. If the absorption chiller is left as it is, the
solution in it may crystallize in 4-5 hours. To prevent
this, dilute the solution. Use the procedure shown in
Manual Refrigerant Blow Down and Diluting Method
on page 137.

TABLE 37 - CHILLED WATER SUSPENSION

ITEM CAUSE
Chilled water pump has a
1
problem.
Chilled water flow rate is
2
Pressure transfer pipe of
3 water suspension switch
is clogged.
Water suspension switch
4
is broken.
If the chiller has a pump problem it does not perform
the dilution operation. It stops immediately. If left as
is, the solution in it may crystallize in 4-5 hours. To
prevent this, contact your local Johnson Controls Ser-
vice Office immediately.
TABLE 38 - PUMPS OVERLOADED OR
OVERHEATED
ITEM
1 Bearings of the pump are worn or clogged.
2 Pump is damaged by cavitation caused by low liquid level.
3
4
Internal cycle control valve is not set properly.
5
6
7
TABLE 39 - CHILLED WATER TIME OUT OR
COOLING WATER TIME OUT
ITEM CAUSE
1 Pump abnormal
2 Insufficient water flow
3 Water suspension relay
abnormal
4 Water pump interlock
abnormal
JOHNSON CONTROLS
Check the chilled water pump for a problem.
Check to see if the chilled water flow rate is below the set point of the water
suspension switch. If it is low, check the flow controller, check the strainer for
low.
clogging, and check the opening ratio of the flow control valve.
Contact your local Johnson Controls Service Office.
CAUSE
Thermal switch is not set properly.
Filter in the pump is clogged.
Solution is crystallized.
Circuit breaker has tripped.
Check the water pump
Check the water line and check the water flow
Check the water suspension relay. Check to see if the pipe is clogged or not.
Check the water pump.
SECTION 8 – TROUBLESHOOTING
COUNTERMEASURE
COUNTERMEASURE
Contact your local Johnson Controls Service
Office.
COUNTERMEASURE
8
159