Indicator Lights; Gas Valve - Dunkirk Q90 150 Installation Manual And Operating Instructions

This section provides a brief description of the key
controls and accessories found in this boiler.
See Section XVII, "Troubleshooting," in this instal-
lation manual for detailed sequences of operation
and troubleshooting procedures. See the separate-
ly provided "Repair Parts Manual" for locations of all
control components and accessories described.
The Integrated Boiler Control (IBC) is a micro-
processor based controller for high efficiency gas
boilers that monitors all safety controls and which
controls the operation of the combustion air blow-
er, 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 indicator lights.
The electronic 24 volt gas control valve contains a
1:1 gas/air pressure regulator to control gas flow to
the main burner d the appliance, is suited for both
natural and LP gas, and is rated in accordance with
ANSI Z21.21 - latest revision and and CGA-6.5-M95.
GAS VALVE
VENTURI VALVE
THROTTLE
/ J-
INLET _ I/_
PRESSURE_ I __
TAP _ I
__AIR PRESSURE
_] _-x_, _ CONNECTION
INLET -- L_ _- OUTLET
,o?xj -T 52 A2E,OVE
HEADER
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 ser-
vice switch off, then back on.
iNDICATOR LIGHTS
f -\
.................. INTEGRATED BOILER CONTROL
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CONTROL PANEL
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The high limit aquastat control determines the maxi-
mum boiler water temperature and also provides a
means for protecting the boiler and heating system
from unsafe operating conditions which could dam-
age the boiler. The aquastat is mounted in the ½" NPT
control well and 3A"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 adjustment for each installation de-
pends on heating system requirements. The aquastat
automatically resets when the boiler water tempera-
ture drops 20°F below the setpoint value. This reset
value can be field adjusted within a range of 5-30°F.
NOTE: The maximum setpoint of the aquastat must not_
xceed 2G0°F.
J
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 mixer. The igniter also serves as a means
for proving the main burner flame by flame rectifica-
tion. In the event of a lack of flame signal on three
consecutive trials for ignition, the IBC will lock out.
The "Valve" and "Flame" diagnostic indicator lamps
(see Figure 16) will blink indicating the failure mode
In the event of lack of or loss of water in the boiler,
the casting temperature safety switch (230°F set-
point) installed on the top of the aluminum boiler
section behind the supply piping shuts off the boiler
by shutting off power to the IBC and causes the
power indicator light to go out. This fault requires
manual reset of the casting temperature safety
switch to restart the boiler. Verify that the boiler
is properly filled with water before resetting this
switch.