PB Heat Gas Boiler - Manual (Page 28)

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ELECTRICAL
Install all electrical wiring in accordance with the National
Electrical Code, ANSI/NFPA 70, and local requirements.
A. WIRING
1. Refer to Figures 6.1 for connecting the power supply
to the boiler.
2. Connect boiler to a 110 volt, single phase, 60 hertz
electrical supply line with a fused disconnect switch.
The boiler is fused for a load of 6.3 amperes.
3. The boiler electrical connection is located on the left
side of the boiler in the junction box which houses
the service switch.
4. Wire the burner service switch in the hot line to the
boiler as shown in Figure 6.1.
5. Make sure to maintain correct polarity on the
incoming power supply wires. If polarity is reversed,
the boiler control will not sense the main burner
flame.
6. Connect the ground wire from the incoming power
supply to the green ground screw in the junction
box. Also, the boiler ground should be connected to
this screw.
7. Figure 6.1 shows connections to system circulator.
a) The maximum current load for the circulator
circuit is 4.0 amperes.
b) For loads greater than 4.0 amps, isolate the
circulator using a switching relay.
c) An example of this wiring using a Honeywell R845A
relay is shown in Figure 6.2
8. The thermostat connections are shown in Figure 6.1
or 6.2. The setting for the thermostat anticipator is
0.56 amps.
9. The boiler control board and factory wiring are
shown in figure 6.3.
B. SEQUENCE OF OPERATION
1. System Power-Up:
a) When power is first applied to the boiler, the
control will initially run through a self-diagnostic
routine. The interface unit shows the system
supply temperature.
b) Next, it will power the combustion air fan for a 10
second purge cycle.
c) Finally the combustion air shuts down and if there
is no call for heat the control board enters a
standby mode.
2. Heating Cycle:
a) When the thermostat calls for heat (closing the
contact between the two gray [TT] wires) and the
boiler control senses a supply temperature lower
than the set point by more than the differential,
the boiler initiates a heating cycle.
b) The control then powers the combustion air fan
at the speed prescribed for the particular boiler
model and performs a 6 second pre-purge of the
combustion chamber.
c) 0.5 second before the pre-purge is complete
power is applied to the spark igniter.
d) Once the pre-purge cycle is complete, the fan
speed decreases to the programmed ignition
speed.
6. ELECTRICAL
This unit 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 current edition of the
National Electrical Code, ANSI/NFPA 70.
NOTICE
Figure 6.1: Wiring Connections to Boiler
Junction Box
Figure 6.2: Wiring Circulator with R845A
Switching Relay