Bryant 479 D - Manual (Page 5)

VI. CHILLED WATER SYSTEM
The cooling section of Model 180-479 is comprised of
two 90,000 BTUH chillers and a 180,000 BTUH
cooling coil which is divided into two separate 90,000
BTUH sections (top and bottom). The bottom section
of the chilled water coil is supplied chilled water by
one chiller (1st stage cooling) while the top section of
the chilled water coil is supplied chilled water by the
other chiller (2nd stage cooling). The chilled water
circuit of each chiller is independent of the other;
therefore, each chiller must be charged with water
before the cooling section can be operated.
The design of Model 240-479 is basically the same as
that of Model 180-479 except the 240-479 utilizes two
120,000 BTUH chillers and a 240,000 BTUH cooling
coil which is divided into two separate 120,000 BTUH
sections. Each chiller of the Model 240-479 must also
be charged with water since the chilled water circuit
of each chiller is independent of the other.
CAUTION: The water seals will be damaged if the
pumps are operated without water in the system.
Freezing conditions will not damage the pumps;
however, do not operate the pumps when the chillers
or chilled water lines are frozen.
Charging the System with Water
Charge the chilled water system with water as
follows:
1. Turn off manual gas valves to both chillers and
turn off electrical power at disconnect switch.
2. Remove access panel from both of the chillers at'
the chiller tank end. Remove chilled water tank lids.
3. Fill both chiller tanks with water having less than
100 ppm chlorides until distributor pans are covered,
or add 12.2 gallons to each chiller of Model 180-479
or 13.6 gallons to each chiller of Model 240-479.
NOTE: If the local tap water has more than 100 ppm
chlorides, charge the chilled water system with
distilled or deionized water. Check the local water
company and/or county agricultural agent for analysis
of tap water being used in your area.
CAUTION: Never use home soft water, water sof­
tening additives, water cleaning compounds, coloring
additives, acidizing materials, stop leak additives, or
other commercial water additives in the chilled water
system.
WARNING: To prevent personal injury, disconnect
condenser fan motor lead in the control box of each
chiller at this time.
4. Replace both chiller tank lids, then start water
pumps.
If water of either chiller does not circulate when the
pumps are started, air may be trapped in the system.
Most chillers are equipped with a Gorman-Rupp
water pump (plastic). On these chillers, it is necessary
to disconnect the chilled water line at the chiller tank
to bleed the air. Operate water pumps until water ap­
pears at the disconnected water line, then reconnect
water line to chiller tank.
If the chiller with the trapped air is equipped with a
Wayne water pump (metal), it is not necessary to
disconnect the water line to bleed the trapped air.
Bleed the air from the pump through the 1/4-inch slot­
ted head valve located on top of the pump discharge.
See Figure 6. Open valve with a screwdriver. Close
valve when a steady stream of water appears.
5. Leak test the chilled water system.
6. Remove operating level drain plug (located on side
of tank) from both chilled water tanks and continue
to operate pumps until water stops flowing from drain
openings.
NOTE: With the pumps running, the water level is
correct for each chiller when water stops flowing from
its drain opening.
7. Replace operating level drain plugs, then turn off
pumps.
8. Refer to “Freezing Weather Protection” on page
6. If freeze protection is required, decide on which
type of antifreeze to use.
The procedure for adding Ucar-17 is given in Step 9.
The procedure for adding methanol antifreeze is given
in Step 10. If antifreeze is not required, disregard
Steps 9 and 10.
9. Adding Ucar-17 Antifreeze - Refer to Table III.
Drain out amount of water from each chiller tank,
equal to amount of antifreeze to be added. Add
required amount of Ucar-17 to each chiller tank.
Recheck operating water level and correct. Do not use
any chilled water additive when using Ucar-17 in the
recommended concentration. Omit Steps 10 and 11.
10. Adding Methanol Antifreeze - Refer to Table III.
Drain out amount of water from each chiller, equal to
amount of antifreeze to be added. Add required
amount of methanol antifreeze. Add the contents of
the chilled water additive package as described in
Step 11.
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