Johnson Controls York YHAU-C, Installation, Operation And Maintenance Manual

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Common district --- 1 month
Treatment for long stoppage of the absorption chiller
If the absorption chiller is stopped for a long time, bacteria in the water or in the tubes can grow.
The bacteria can corrode the tubes. When stopping the chiller for more than 15 days, drain the
water from the absorber, condenser, evaporator, and the generator through the drain valve at the
bottom of the waterbox.
Chemical treatment
Corrosion inhibitors are attracted chemically to corroded metal surfaces. Or, they form inert
protective compounds over the metal surfaces. For effective use of the corrosion inhibitors,
choose the correct type and concentration. Water quality, temperature, flow speed, metals used,
existence of crevices and deposits and type of water system are also part of the equation. For more
information about corrosion preventive measures, consult a water treatment company.
Flow speed in tubes
As the water flow speed in the tubes is closely related to any existing corrosion, do not increase the
water supply rate more than suggested. If the flow speed reaches 11.6 to 16.3 ft/s, the tubes can
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 can corrode the tube.
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.
Install a strainer on the inlet side of the heat exchanger and clean the strainer periodically.
Storage method of the chiller
If the chiller needs to be stored long-term, the storage method varies. The machine room
temperature condition and the storage period must be considered. If the machine room
temperature is lower than 32°F, drain off the chilled water, cooling water, and the steam
condensate (drain). Dry the tube interiors. Make sure all equipment installed in the chilled water,
cooling water, and steam condensate (drain) lines are completely dry.
Nitrogen gas pressurization inside the absorption chiller is required when the storage period
exceeds 6 months. Contact your local Johnson Controls Service Center for more details.
DANGER
The chiller is not explosion proof. Do not handle or store highly flammable items, gas, or liquids, near
the chiller. Failure to do this can result in explosion, injury, or damage to the equipment and building.
There are two storage methods available for the chiller during off-season (winter) or plant
suspension; the wet storage method and the dry storage method. (The wet storage method is
available where the chilled water and the cooling water will not freeze.)
Each storage method has its own characteristics. Select the method to use based on the plant’s
features and the storage period. Details follow.
YHAU-C Single Effect Steam-Fired Absorption Chiller 158