Patterson-Kelley MOD-04 - Manual (Page 15)

Modu-Fire
®
Gas-Fired Boiler Installation
12
Consideration must be given to all possible condi-
tions and their consequences.
Piping With Refrigeration Machines
When used with a refrigeration system, the boiler
shall be installed so that chilled medium is piped in
parallel with the boiler. Valves should be installed
to prevent chilled water from entering the boiler
when the system is operated in the cooling mode.
Piping With Air Handling Units
The boiler piping system of a hot water heating
boiler connected to heating coils located in air han-
dling units, where they may be exposed to refriger-
ated 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.
3.8.2 Boiler Inlet and Outlet Connections
Boiler Inlet and Outlet Connections
Make water connections as the application warrants,
or at a minimum, as shown, but always in compli-
ance with the local requirements.
Note: Pipe unions and isolating valves must be
installed in both water connections for ease of
service.
The bottom connection to the boiler is the INLET
and must be used for the return from the system.
The top connection to the boiler is the OUTLET and
must be connected as the supply to the system.
Piping must be installed such that no piping stresses
are transmitted to the boiler. The boiler should not
be used as a pipe anchor.
3.8.3 Boiler Water Piping by Installer
Strainer
To avoid possible contamination of the boiler with
dirt, rust or sediment from the system, a strainer
near the boiler inlet is strongly recommended. Even
new systems may contain sufficient foreign material
to eventually reduce the performance of the heat
exchanger. Adequate circulation of good clean wa-
ter is essential to maximum efficiency and long life
of the boiler.
Relief Valve and Piping
Each boiler is supplied with a pressure-relief valve
sized in accordance with ASME requirements. The
relief valve should be piped to a suitable floor drain.
Reducing couplings or other restrictions are not
permitted in the discharge line.
Low Water Cut-off
The boiler is furnished with a flow-switch-type low
water cut-off as required by Section IV ASME
Code; no field piping is required. If the flow switch
does not sense water flow, the boiler will shut down
and a red indicator will be illuminated on the control
panel. This flow switch only proves that flow is
present. It does not prove adequate flow as required
by this boiler.
Installation of an external low water cutoff or man-
ual reset low-water switch may be required by cer-
tain codes or in certain installations. Consult your
local code for details.
Boiler
Drain
Isolating
Valve
Relief Valve
Drain
Union
Isolating
Valve
Outlet (to
system)
Inlet (from
system)
Strainer
Isolating
Valve