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Systems with multiple zones may require an additional circulator. Consult manufacturer's data for valve pressure
drops. When an indirect water heating system is used, it is recommended that a separate circulator be installed
to meet the required flow and pressure drop conditions of the indirect water heater.
We recommend that the make-up water from the cold water line have a check valve, gate valve, and feedwater
regulator set at 12 psig. Install unions and gate or ball valves at inlet and outlet connections at the boiler to facilitate
servicing.
The pressure relief valve is mounted on the boiler and must be piped to a drain. We recommend that all high
points be vented and that purge valves be installed. A boiler installed above radiation level must be provided with
a low water cut-off device. See page 22 for wiring hook-up. The boiler, when used in connection with a refrigeration
system, must be installed so that the chilled medium is piped in parallel with the boiler with appropriate valves to
prevent the chilled medium from entering the boiler.
The boiler piping system of a hot water heating boiler, that is connected to heating coils located in air handling
units where they may be exposed to refrigerated air circulation, must be equipped with flow control valves or other
automatic means to prevent gravity circulation of the boiler water during the cooling cycle.
A diaphragm expansion tank should be installed in the return line. A typical 8" -diameter expansion tank can
be used on models H-0030, H-0042, and H-0066, and an 11"-diameter expansion tank can be used on models H-
0090, H-0135 and H-0180. Consult tank manufacturer for correct sizing.
PIPING DIAGRAMS
12
SINGLE-ZONE PIPING
Fig.# 8997.1
AIR
SCOOP
AIR
VENT
FEED
VALVE
DIAPHRAGM
EXPANSION TANK
HEATING UNITS
COLD
WATER
INLET
PIPE PRESSURE
RELIEF VALVE
TO DRAIN