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SECTION 7 – MAINTENANCE
If the chiller-heater runs without the
valves completely open, a strong turbulent
flow can be generated. The turbulence
may cause damage in the water chamber
case and the copper tube of the chiller-
heater. If you need to adjust the flow rate
of the chilled / hot water, cooling water,
and waste hot water, be sure to adjust the
valves installed at the outlet side of the
chiller-heater.
• Install a safety valve on the waste hot water line.
• Install an expansion tank on the waste hot water
line if the waste hot water is a closed system.
CHEMICAL WATER TREATMENT
Since the mineral content of the water circulated
through the evaporator, condenser, absorber, and waste
hot water heat exchanger varies, the water used may
corrode the tubes or deposit heat resistant scale in them.
Perform a chemical analysis of the water before the
system is installed. Consult a reliable water treatment
company to determine if treatment is necessary. If it
is, the company can provide treatment for the water to
help prevent damage to the tubes.
REPLACEMENT OF WATER
If the chilled / hot water line, and/or the cooling water
line are open systems, they must be cleaned or replaced
periodically. If the water is not treated at all in the wa-
ter line, the recommended intervals for replacement of
both types of water are:
District polluted with sulfurous acid gas --- 5 days
Common district --- 10 days
If the water is blown manually or automatically, the
replacement period may be lengthened as follows.
District polluted with sulfurous acid gas --- 1 month
Common district --- 1 month
108
TREATMENT FOR LONG STOPPAGE OF THE
ABSORPTION CHILLER-HEATER
If the absorption chiller-heater is stopped for a long
time, bacteria in the water or in the tubes may grow.
The bacteria can corrode the tubes. When stopping the
chiller-heater for more than 15 days, drain the water
from the absorber, condenser, evaporator, and waste
hot water heat exchanger through the drain valve at the
bottom of the waterbox.
CHEMICAL TREATMENT
Corrosion inhibitors are attracted chemically to metal
surfaces when they are corroded. They may also form
inert protective compounds over the metal surfaces.
For effective use of the corrosion inhibitors, the correct
type must be selected. The concentration must also be
determined according to the conditions in the chiller-
heater. Water quality, temperature, flow speed, metals
used, existence of crevices and deposits, and type of
water system are factors that must be considered. For
the complete corrosion preventive measure, consult a
water treatment company.
FLOW SPEED IN TUBES
Since the water flow speed in the tubes is closely relat-
ed to tube corrosion, do not increase the water supply
rate more than recommended. If the flow speed reaches
3.5 to 4 meters per second, the tubes may be damaged.
When changing the flow rate, contact your local John-
son Controls Service Center for help.
If the water supply rate is adjusted at the inlet side of
the heat exchanger, the eddy current at the inlet may
damage the tube.
Be sure to control the flow rate on the outlet side as
well.
The eddy current caused by foreign matter in the heat
exchanger is also a large factor of corrosion. Be sure to
install a strainer on the inlet side of the heat exchanger
and clean the strainer periodically.
FORM 155.33-ICOM2.EN.GB
ISSUE DATE: 12/4/2017
JOHNSON CONTROLS
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Troubleshooting
