SECTION 7 – MAINTENANCE
FORM 155.32-ICOM2.EN.UL
ISSUE DATE:1/10/2018
146
JOHNSON CONTROLS
TREATMENT FOR LONG STOPPAGE OF THE ABSORPTION
CHILLER-HEATER
If the absorption chiller-heater is stopped for several days, 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, and evaporator through
the drain valve at the bottom of the waterbox.
CHEMICAL TREATMENT
Corrosion inhibitors are attracted chemically to the metal surfaces when the latter are
corroded or they form inert protective compounds over the metal surfaces. For effective
use of the corrosion inhibitors, types of inhibitors must be selected and their concentration
must be determined according to the conditions of the chiller-heater system. In those
conditions, water quality, temperature, flow speed, metals used, existence of crevices and
deposits and type of water system must be included. 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 related to any existing 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 erode. When changing the flow rate, contact your local
Johnson Controls Service Center.
If the water supply rate is adjusted at the inlet side of the heat exchanger (evaporator,
condenser, and absorber), the eddy current at the inlet may corrode the tube.
Be sure to control the flow rate on the outlet side.
The eddy current caused by foreign matter in the heat exchanger is also a factor in
corrosion. Be sure to install a strainer on the inlet side of the heat exchanger and clean the
strainer.
