Dunkirk XEB-2 Installation Instructions Manual page 19

All electrical work must conform to local codes as
well as the National Electrical Code, ANSI/NFPA-70,
latest revision. In Canada, electrical wiring shall comply
with the Canadian Electrical Code, CSA-C22.1.
ELECTRIC POWER SUPPLY
Run a separate 120 volt circuit from a separate
overcurrent protective device in the electrical service
entrance panel. This should be a 15 ampere circuit.
Locate a shut-off switch at the boiler. It must be turned
off during any maintenance. Connect 120 volt power
supply to aquastat terminals L1 (HOT) and L2.
The boiler, when installed, must be electrically
grounded in accordance with the requirements of
the authority having jurisdiction or, in the absence of
such requirements, with the National Electrical Code,
ANSI/NFPA No. 70-latest revision. Run a 14 gauge
or heavier copper wire from the boiler to a grounded
connection in the service panel or a properly driven
and electrically grounded ground rod.
WARNING
Tum off electric power at fuse box before making any
line voltage connections. Follow local electrical codes.
INSTALL YOUR THERMOSTAT
The thermostat location has an important effect on the
operationof yourboilersystem BE SURETO FOLLOWTHE
INSTRUCTIONSINCLUDEDWITHYOUR THERMOSTAT
Locatethe thermostat aboutfive feet above the floor on an
inside wall. tt may be mounted directly on the wall or on a
vertically mounted outlet box. Itshould besensing average
roomtemperature,so avoidthe following:
DEAD SPOTS:
Behind doors
Corners and alcoves
HOTSPOTS:
Concealedpipes
Fireplace
TV sets
Radios
Lamps
Directsunlight
Kitchens
COLD SPOTS:
Concealedpipes or ducts
Stairwells- drafts
Doors-drafts
Unheated room on other side of wall
Set heat anticipatorat .2 amps.24 volt thermostatconnects
to aquastatterminals T and T
1. Thermostat calls for heat, powering the 1K relay
coil and closing contacts 1 K1 and 1 K2.
2. Circulator pump is powered through terminals
C1 and C2.3. Induced draft blower and AT140C
transformer primary are powered through
terminals B1 and B2.
4. When blower gets up to speed and blower
suction pressure reaches pressure switch
setpoint, pressure switch contacts close sending
24 volts to $8600 intermittent pilot control from
AT140C transformer secondary.
5. Pilot gas valve opens and spark initiates to light
pilot burner. 6. When pilot flame is proven, spark
drops out.
7. Main gas valve opens and pilot burner ignites
main burners.
8. If boiler water temperature reaches high limit
setpoint, high limit contacts B-R open, cutting power
to blower and $8600 intermittent pilot control.
Burners extinguish and blower stops. Circulator
pump continues to run as long as the thermostat
continues to call for heat. When boiler water
temperature drops past the high limit setpoint
and through the differential, high limit contacts
B-R close, repeating steps 3-7.
9. If venting system becomes blocked, blower
suction pressure will drop below the pressure
switch setpoint, opening the pressure switch
contacts and cutting power to the $8600
intermittent pilot control. Burners will extinguish,
but blower will remain powered as long as the
thermostat continues to call for heat. If venting
system clears, steps 4-7 will repeat.
10. Thermostat is satisfied, ending call for heat.
Relay coil 1 K is de-energized, opening 1K1
and 1K2 contacts. Burners extinguish. Blower
and circulator pump stop.
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