14
A06090
Fig. 17
---
Ladder Wiring Diagram
STEP 8
—
Controls and Accessories
This section provides a brief description of the key controls and
accessories found in this boiler.
See
Troubleshooting
in the Service Hints section of this
installation manual for detailed sequences of operation and
troubleshooting procedures. See the
Repair Parts
section of this
manual for locations of all control components and accessories
described.
INTEGRATED BOILER CONTROL (IBC)
The Integrated Boiler Control (IBC) is a microprocessor based
controller for a high efficiency gas boiler that monitors all safety
controls and controls the operation 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 of the boiler and contains five diagnostic indicator lights.
(See Fig. 18 and Table 4.)
GAS CONTROL VALVE
The electronic 24 volt gas control valve contains a 1:1 gas/air
pressure regulator to control the gas flow to the main burner of
the appliance and is suited for natural and propane gases. The
valve is rated in accordance with ANSI Z21.21--latest revision
and CGA--6.5--M95. (See Fig. 19.)
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 mixer. The igniter also serves as
a means for proving the main burner flame by flame rectification.
In the event of a lack of flame signal on three (3) consecutive
trials for ignition, the IBC will lockout. The “VALVE” and
“FLAME” diagnostic indicator lamps (lamp “D” and “E” on the
IBC, see Fig. 18) will blink indicating 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.
L4006A 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 operating conditions
which could damage the boiler. The aquastat is mounted in the
1/2” NPT control well and 3/4” x 1/2” 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 depends on heating system requirements. The
aquastat automatically resets when the boiler water temperature
decreases 20
_
below the setpoint value. The reset value can be
field adjusted within a range of 5 to 30
_
F.
NOTE
: The maximum setpoint of the Aquastat must not exceed
200
_
F.
CASTING TEMPERATURE SAFETY SWITCH
In the event of lack of or loss of water in the boiler, the Casting
Temperature Safety Switch (230
_
F setpoint) installed on the top
of the aluminum boiler section behind the supply piping shuts off
the boiler by shutting off power to the Integrated Boiler Control
(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.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit damage.
Never run cold water into a hot, empty boiler.
CAUTION
!
