Appliance Operation - Baxi 100/2 HE Plus Installation & Servicing Instructions Manual

Mains On.
Flow
temperature less
than set point ?
YES
10 second
Pump On.
NO
Flow switch made ?
YES
5 second
Fan Pre-Purge.
5 second
Ignition Period.
Flame Detected ?
YES
Burner On.
All TRVs
shut or Flow temperature
greater than set point ?
YES
5 second
Fan Post Purge.
YES
All TRVs
shut down ?
NO
1 minute
Pump Overrun.
3 minute
Anti-cycle.
NO
Ignition done
YES
and less than 5
attempts made ?
Ignition done and
5 attempts made ?
YES
Ignition
Lockout.

3.0 Appliance Operation

3.1
1. Switched Live On: When the switched live switches
on if the flow temperature is less than the set point
then pump overrun occurs. When the switched live
switches on if the flow temperature is greater than the
set point then pump overrun occurs.
2. Pump On: The pump is on while the fan, spark
generator and gas valve are off. After 10 seconds if the
flow switch has made then fan pre-purge occurs. After
10 seconds if the flow switch has not made then anti-
cycle occurs.
3. Fan Pre-Purge: The pump and fan are on while the
spark generator and gas valve are off. After 5 seconds
ignition occurs.
4. Ignition: The pump, fan, spark generator and gas
valve are on. If a flame is detected then burner on
occurs. If a flame is not detected within 5 seconds and
less than 5 ignition attempts have been made then fan
purge occurs. If a flame is not detected within 5 seconds
and 5 ignition attempts have been made then ignition
lockout occurs.
5. Burner On: The pump, fan and gas valve are on while
the spark generator is off. Flow temperature is
controlled by varying the fan speed (and thereby the
gas rate) to achieve optimum operation. If the flow
temperature is greater than the set point or the TRVs
all shut down then fan post purge occurs.
6. Fan Post Purge: The pump and fan are on while the
spark generator and gas valve are off. After 5 seconds if
the TRVs are not shut down then pump overrun
occurs. After 5 seconds if the TRVs are shut down then
anti-cycle occurs.
7. Pump Overrun: The pump is on while the fan, spark
generator and gas valve are off. After 1 minute anti-
cycle occurs.
8. Anti-cycle: The pump, fan, spark generator and gas
valve are off. After 3 minutes if the flow temperature is
less than the set point then pump on occurs. After 3
minutes if the flow temperature is greater than the set
point then pump overrun occurs.
9. Ignition Lockout: The pump, fan, spark generator and
gas valve are off. The boiler can only be reset by
manually using the reset button.
7