Terminal 4 –Ignition wiring
The output terminal normally powers a high voltage transformer. Route the high voltage
ignition wiring a sufficient distance from all sensors and other low voltage wiring to avoid
electrical interference, which may cause erratic operation of the SBSeries system. Keep the
high voltage wire as short as possible. The best condition is to mount the ignition transformer
close to the burner and keep a low impedance path from the burner ground to the ground of
the transformer. Make sure the high voltage lead and ground return paths do not create a loop
antenna around the SBSeries and sensor wiring.
Low Fire Start Switch, (Terminal 3 –resistance through valve coil)
For modulation sequence models: It is possible to wire the system for checking low fire start
position prior to pilot ignition. To use this feature, the low fire start switch must be connected
between terminal 3 and the pilot valve. On direct spark burners, a by-pass contact must be
wired around the low fire switch.
Terminal V or D - Main Valve Closed Switch Input
The system can be wired to check for the main valve closed switch on the main gas valve prior
to start-up and after the end of the burner cycle.
For purge and no purge models: The main valve closed switch must be connected to
Terminal V and the jumper in the base must be cut.
For modulation models: The main valve closed switch must be wired in series between the
airflow switch and the high purge damper switch. To use this feature, the jumper in the base
must be cut.
Terminal D - High Purge Switch Input
For modulation models: the system can be wired to check high purge position for the high fire
purge portion of the sequence. To use this feature, the red jumper in the base must be cut and
the high purge position switch must be connected from terminal If this feature is not used, the
jumper in the base remains intact a jumper must be installed between terminals 1 and D. (The
yellow jumper on the base has no effect whether cut or intact.)
Terminal 1 - Remote Reset
This feature permits remote mounting of a switch to reset the SBSeries. To use this feature, a
normally closed remote reset switch must be wired so that power is interrupted to terminal 1.
When it is pressed or actuated, the connection to terminal 1 is momentarily interrupted and resets
the SBSeries.
Remote Display
The SB20896 remote display is wired according to Figure 10. Mount through a DIN cutout
using the two supplied brackets in either the top and bottom or the side slots. Locate the display
and wiring to minimize electrical interference. Applying and disconnecting the display power
supply should coincide with power to terminal 1 of the SBSeries. Use the appropriate cable
(P/N SB20318) to connect to the test jack and to the S2 terminal of the SBSeries wiring base.
Do not attempt to parallel the test jack signal to other devices when using a remote display.
The LCD display contrast can be adjusted on the back with a small blade screwdriver.
Note:
1. Control circuit wires must meet 90°C (194°F) specification minimum and must be 1.5mm
(No. 16 AWG) or larger and in accordance with all applicable codes.
2. Flame sensor wires must be individually run in their own separate conduit; multiple
unshielded flame sensor wires CANNOT be run together in a common conduit or wire
way (See Sensor Installation Section).
3. The neutral wire to terminal 2 must be at ground potential (bonded at the supply source).
