Circulator Pump - Dunkirk 90-50 Installation, Operation & Maintenance Manual

draft inducer
The draft inducer (blower) provides a means for pulling combustion
air into and through the mixer, the burner, the flue ways of the
cast aluminum boiler sections and the flue adapter before being
discharged through the vent piping to the outdoors. See applicable
sections for proper sizing and installation of combustion air and vent
piping in this manual.

Circulator pump

Every forced hot water system requires at least one circulating pump.
The circulating pump imparts the necessary energy to move the
water through the closed loop supply and return piping systems,
terminal heating equipment (i.e. finned tube radiators, etc.) and back
through the boiler for reheating. To provide the required hot water
flow rates, the circulator 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 for a single zone or zone valve controlled heating system and
should be correctly located on the downstream (i.e., pumping away)
side of the expansion tank. For a pump controlled system (where
there is a circulator for each zone) the circulator provided with
the boiler can work for one zone. For more details on piping and
circulators, see Near Boiler Piping section (page 12 of this manual).
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 ¾" tapping at the bottom of the front 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.
a.s.m.e. rated pressure relief Valve
Each boiler must have a properly sized and installed American
Society of Mechanical Engineers rated 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 inside 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 piping same size
as the valve discharge opening to an open drain, tub or sink, or other
suitable drainage point not subject to freezing, in accordance with
A.S.M.E. 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.
ConTrols and aCCessories
blocked Vent safety shutoff
This boiler is equipped with a blocked vent safety shutoff means,
which shuts off main burner gas in the event that the flow of
combustion products through the flueways is reduced. In the event
of blocked flueways, enough air will not be available to support
combustion, and the S9301 Integrated Boiler Control (IBC) will
lockout due to loss of adequate air flow (after 3 trials for ignition).
The "PURGE" diagnostic indicator lamp (lamp "B" on the IBC,
see Figure 16) will blink indicating the failure mode as a lack of
adequate air flow. The IBC is manually reset from lockout by either
removing and re-establishing the thermostat's call for heat, or by
turning the service switch OFF, then back ON. If the boiler cannot
be restored to normal operating condition by resetting the control,
contact a qualified service agency to check heat exchanger flueways
for blockage.
external Condensate pump (optional)
For installations where there is no floor drain or other appropriate
drainage receptacle available to receive condensate from the boiler,
an external float activated condensate pump with integral sump is
required. This unit can be installed to pump the condensate to a
remote tie in point to a sanitary 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 blocks to raise boiler as required for proper
installation.
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