Raypak RAYTHERM 0133-4001 - Manual (Page 17)

RECOMMENDED PURGE MANIFOLDS FOR
TYPICAL HYDRONIC SYSTEM HOOKUPS
The boiler piping system of a hot water heating
boiler connected to heating coils located in air handling
units where they may be exposed to refrigerated air
circulating, must be equipped with flow control valves
or other automatic means to prevent gravity circulation
of the boiler water during the cooling cycle.
TEMPERATURE & PRESSURE GAUGE
The temperature & pressure gauge is standard
equipment on all hydronic heating and hot water supply
boilers. All temperature & pressure gauges are factory
mounted in the in/out header except for residential
boilers, Models 133 and 181-401. On these models the
temperature & pressure gauge is shipped loose for
field installation, and located in the outlet water
connection. All fittings required to mount gauge to
piping system are supplied by others.
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PUMP SELECTION
In order to ensure proper hydraulics in your
hydronic heating system, adequate pump size must be
selected. We recommend that the pump be sized for
20°F Delta T. (Delta T is the temperature difference
between the inlet and outlet water when the boiler is
firing at full rate). For some boilers, the Delta T is more
than 20°F (22°-33°F) at the recommended flow rates.
FEEDWATER REGULATOR
We recommend that a feedwater regulator be
installed and set at 12 PSIG minimum pressure. Install
a check valve or back flow device upstream of the
regulator, with a manual shut-off valve. Leave the
valve open.
PIPING - HEATING BOILERS
We recommend that all high points be vented and
that purge valves and a bypass valve be installed. A
boiler installed above radiation level must be provided
with a low water cut-off device. The boiler, when used
in conjunction 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.