www.DaikinApplied.com 13 IOM 1274-3 • CENTRIFUGAL WATER CHILLERS
supplied by the customer (see Figure 5).
in heat recovery mode during part load operation if the supply
temperature to the heat recovery condenser is held constant by
the tower bypass valve. Also, it is important to size the cooling
tower for full condenser heat rejection if the heating load
requirements are expected to vary, especially during summer
months. Contact a Daikin Applied representative to review
Figure 5: Heat Recovery System Schematic
Relief Valves
As a safety precaution and to meet code requirements, each
chiller is equipped with pressure relief valves located on
the condenser and evaporator for the purpose of relieving
excessive refrigerant pressure (caused by equipment
Table 5: Cenrifugal B-vintage Relief Valve Data
Evaporator Condenser
Location Top Top Top
Setting (psi) * 200 225 200
Discharge Capacity
(lb/min air)
75.5 84.4 5
Qty
1 for 12’ shells
2 for 16’ shells
2 for 12’
shells
4 for 16’
shells
1 for
079-126
models
Connection Size 1.0-inch NPT
3/8-inch
NPT
Most codes require that relief valves be vented to the outside
of a building. Relief piping connections to the relief valves must
CAUTION
Units are shipped with refrigerant valves closed to isolate the
refrigerant in the unit condenser. Valves must remain closed
until startup by the factory service technician.
Remove plastic shipping plugs (if installed) from the inside of
the valves prior to making pipe connections. Whenever vent
piping is installed, the lines must be in accordance with local
code requirements; where local codes do not apply, the latest
issue of ANSI/ASHRAE Standard 15 code recommendations
must be followed.
Condenser Relief Valves
In order to ensure proper installation, it is important to know
how the three-way relief valve functions. One valve remains
active at all times and the second valve acts as a standby.
When the stem of the three-way valve is pushed into the valve
of the three-way valve is pulled back completely, the valve is in
front outlet port, as shown in Figure 6.
Figure 6: Condenser Three-Way Relief Valve Three-Way
Valve, Front Seated Position
EVAPORATOR
TOWER
CONDENSER
RECOVE RY
CONDENSER
AUXILIARY
HEATER
HEAT LOAD
TC
TC
COOLING
LOAD
OPEN
CIRCUIT
TOWER
HEAT RECOVERY
CHILLER
LEGEND
P U MP
TC TEM PE RA TUR E C O N TR OL P OIN T
Three-Way Valve
Relief Valves
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