21
Air Proving blocked vent safety Assembly
The air proving blocked vent safety assembly incorporates
two pressure switches that are designed to discontinue op-
eration of the appliance if there is a problem with the blower
or venting system. The normally open switch closes upon
the initiation of the blower and functions as an air proving
switch. The normally closed switch opens if there is a block-
age in the combustion air intake or exhaust vent pipes.
Drain valve
The manual drain valve provides a means of draining the
water in the heating system, including the boiler and hot
water supply and return piping systems installed above
the drain valve. This drain valve is installed in the return
piping at the bottom front of the boiler section. Any piping
installed below the elevation of this drain valve will require
additional drain valves to be installed at low points in the
piping systems in order to drain the entire system.
AsmE Rated Pressure Relief valve
Each boiler must have a properly sized and installed
American Society of Mechanical Engineers (ASME) rat-
ed pressure relief valve. Water expands as it is heated
by the burner/boiler sections. If there is no place for the
water to expand its volume, (i.e., a properly sized and
properly functioning expansion tank) pressure on the in-
side of the boiler and heating system will increase. The
furnished relief valve will automatically open at 30 psig
pressure to relieve the strain on the boiler and heating
system from the increasing pressure. The pressure relief
valve discharge must be piped with the same size pipe as
the valve discharge opening to an open drain, tub or sink,
or other suitable drainage point not subject to freezing, in
accordance with ASME specifications. Failure to provide
the pressure relief valve with piping as herein described
may cause water damage and/or serious bodily injury.
The boiler manufacturer is not responsible for any water
damage or personal injury. Check local codes for maxi-
mum discharge height from floor.
External Condensate Pump (optional)
For installations where there is no floor drain or other ap-
propriate drainage receptacle available to receive conden-
sate from the boiler, an external float activated conden-
sate pump with integral sump is required. The condensate
pump can be piped to a remote tie in point to a sani-
tary sewer system. For this application, the boiler must
be installed so that proper pitch of piping to the external
condensate reservoir (sump) can be accomplished. Use
wood frame or concrete blocks to raise boiler as required
for proper installation.
Concentric vent/Air Intake Termination (Optional)
The optional concentric vent/air intake termination utilizes
a single opening per each appliance through the wall or
roof of a structure.
XI - CONTROLs AND ACCEssORIEs
on Cam Vent at the heat exchanger) before reset-
ting this switch.
Never run cold water into a hot, empty boiler.
WARNING
!
Circulator Pump
Every forced hot water system requires at least one circu-
lating pump. The circulating pump imparts the necessary
energy to move water through the closed loop supply and
return piping systems, terminal heating equipment (finned
tube radiators, etc.) and back through the boiler for reheat-
ing. To provide the required hot water flow rates, the circu-
lator pump must be properly sized to overcome frictional
losses (usually measured in feet of water, also referred
to as “pump head loss”) of the supply and return piping
systems and boiler. The circulator pump is furnished in a
carton within the boiler cabinet. The circulator(s) should
always be located on the downstream (“pumping away”)
side of the expansion tank.
