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Winter Shutdown Preparation
Dry Layup Shutdown
Rooms where chillers have chance of freezing or coming in
contact with hot water:
1. Close chilled water and condenser water isolation
valves (if available).
2. Drain chilled water and condenser water barrels.
a. If valves were not available both loops will need to
be drained completely.
3. Remove condenser and chilled water bell ends.
a. If chiller is single or three pass, one pipe end should
be removed.
4. Using nitrogen or an air compressor blow out all tubes
to ensure no water is left inside.
Wet layup Shutdown – Unheated Rooms
Rooms where chillers will have chance of freezing but not
connected to the boiler loop:
1. Close chilled water and condenser water isolation
valves (if available).
a. If valves are not available, they will need to be
installed.
2. Drain chilled and condenser water barrels.
3. Completely fill the barrels with an appropriate amount
of ethylene glycol solution for 15˚F (8.3˚C) below the
expected low ambient condition.
4. Leave the barrels full of the solution until startup.
5. Mark the barrel stating what was left inside for
precautions next season.
Wet layup Shutdown – Heated Rooms
Rooms that are heated and will not have contact with hot
water:
1. Close chilled water and condenser water isolation
valves (if available).
a. If valves are not available, they will need to be
installed.
2. Talk to local chemical treatment company for correct
chemical treatment for water left in barrel over winter.
a. If treatment needs to be changed, make proper
arrangements.
Maintenance Tasks
The maintenance tasks described herein present the basic,
minimal, steps required to successfully complete a task.
Local policies and protocols may require more elaborate
procedures with additional checks and inspections.
ARTC-SVX014A-EN
Critical Cleaning Tasks
Flooded Shell and Tube Heat Exchanger
Cleaning Tasks:
NOTICE
Proper Water Treatment Required!
The use of untreated or improperly treated water
could result in scaling, erosion, corrosion, algae or
slime.
Use the services of a qualified water treatment
specialist to determine what water treatment, if any, is
required. Trane assumes no responsibility for
equipment failures which result from untreated or
improperly treated water, or saline or brackish water.
Condenser tube fouling is suspect when the approach
temperature (i.e., the difference between the refrigerant
condensing temperature and the leaving condenser water
temperature) is higher than predicted. Standard water
applications will operate with less than a 9°F approach. If
the approach exceeds 9°F and there is noncondensable in
the system, cleaning the condenser tubes is
recommended.
Note: Glycol in the water system typically doubles the
standard approach. If the annual condenser tube
inspection indicates that the tubes are fouled, 2
cleaning methods can be used to rid the tubes of
contaminants.
Mechanical Cleaning Procedure
This method is used to remove sludge and loose material
from smooth-bore evaporator/condenser tubes.
1. Remove the retaining bolts from the water boxes (if
equipped) at each end of the evaporator and
condenser. Use a hoist to lift the water boxes.
2. Work a round nylon or brass bristled brush (attached to
a rod) in and out of each of the water tubes to loosen
the sludge.
3. Thoroughly flush the evaporator/condenser water tubes
with clean water (To clean internally enhanced tubes,
use a bi-directional brush or consult a qualified service
organization for recommendations).
Chemical Cleaning Procedure
Scale deposits are best removed by chemical means.
Consult a qualified water treatment specialist (one that
knows the local water supply chemical/mineral content) for
a recommended cleaning solution suitable for the job. (A
standard condenser water circuit is composed solely of
copper, cast iron and steel.)
Improper chemical cleaning can damage tube walls. All of
the materials used in the external circulation system, the
quantity of the solution, the duration of the cleaning period,
and any required safety precautions should be approved by
the company furnishing the materials or performing the
cleaning.
Maintenance Procedures
73
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