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This section provides a brief description of the key
controls and accessories found in this boiler.
See Section XVII, "Troubleshooting," in this installa-
tion manual for detailed sequences of operation and
troubleshooting procedures. See the separately pro-
vided "Repair Parts Manual" for locations of all control
components and accessories described.
IntEgRatEd BoIlER contRol (IBc)
The Integrated Boiler Control (IBC) is a microproces-
sor based controller for high efficiency gas boilers that
monitors all safety controls and which controls the op-
eration of the combustion air blower, circulator pump,
burner, and a combination hot surface igniter/flame
sensor. This controller is not intended for use with a
vent damper. This controller is mounted on the control
panel inside the boiler and contains five diagnostic in-
dicator lights.
gas contRol ValVE
The electronic 24 volt gas control valve contains a 1:1
gas/air pressure regulator to control gas flow to the main
burner of the appliance, is suited for both natural and LP
gas, and is rated in accordance with ANSI Z21.21 - lat-
est revision and CGA-6.5-M95.
gas ValVE
Hot suRFacE IgnItER
The 120 volt hot surface igniter heats up to 1800°F to
initiate combustion of the gas in the burner. The igniter
is mounted next to the burner through the gas/air mix-
er. The igniter also serves as a means for proving the
main burner flame by flame rectification. In the event of
Xi. coNtrols aND accessories
Figure #15
a lack of flame signal on three consecutive trials for ig-
nition, the IBC will lock out. The "Valve" and "Flame" di-
agnostic indicator lamps (see Figure #16) will blink in-
dicating the failure mode as a lack of flame signal. The
IBC is manually reset from lockout by either removing
and reestablishing the thermostat's call for heat, or by
turning the service switch off, then back on.
IndIcatoR lIgHts
HIgH lIMIt aQuastat contRol
The high limit aquastat control determines the maximum
boiler water temperature and also provides a means for
protecting the boiler and heating system from unsafe op-
erating conditions which could damage the boiler. The
aquastat is mounted in the ½" NPT control well and ¾"
x ½" bushing on the top of the front boiler section at the
hot water outlet. The aquastat is tied in with the IBC and
is factory set at 180°F water temperature. The high limit
setpoint is field adjustable and may be set anywhere
between 100°F and 200°F. The field setpoint adjust-
ment for each installation depends on heating system
requirements. The aquastat automatically resets when
the boiler water temperature drops 20°F below the set-
point value. This reset value can be field adjusted within
a range of 5-30°F.
notE: The maximum setpoint of the aquastat
must not exceed 200°F.
20
Figure #16
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