Burner Program Sequence Of Operation - Viessmann VITODENS 200-W Service Instructions Manual

Additional Information

Burner Program Sequence of Operation

Phase 0: Stand-by
Complete shutdown until the next call for heat. In this
phase both the combination gas valve and the blower
are not energized.
Phase 1: Stand-still status test (blower)
A call for heat initiates internal blower sensory
communications to confirm that the blower is truly in
stand-still position. Blower speed measured must be
< 300 rpm within a 51 second period.
Phase 2: Pre-purge speed test
Controller sends and receives signal to / from fan speed
controller to verify maximum rpm of the blower.
Phase 3: Pre-purge
Pre-purge cycle starts within the pre-programmed timing.
Pre-purge timing is in addition to previous phase (2).
The fan speed must be greater than and within the range
of rpm requested by the controller.
Phase 4: Pre-ignition
The ignition spark is initiated and controlled.
Phase 5: Ignition / safety timing / flame stabilization
The gas valve opens during the safety timing period
(4.5 seconds). If a flame is detected, this phase ends
immediately in < 1.5 seconds. If the flame is not
established after 3 trials, the burner will lock out and will
require a manual reset. Controller required time for flame
stabilization.
92
Vitodens 200-W B2HA 112, 150 Service
Phase 6: Burner modulation operation or calibration
At the end of the flame stabilization period (4.5 seconds.),
a release for modulation occurs and the burner temperature
controller will take over from the flame safeguard. Forced
shutdown after 24 hours continuous operation. Automatic
calibration may be initiated by the controller.
Phase 7: Combination gas valve proof of closure test
If during the normal operation of the burner a controlled
(or uncontrolled) shut-down occurs, a complete mechanical
and electrical gas valve proof of closure test will be
performed by the flame safeguard. After a successful
mechanical and electrical proof of closure test, the flame
safeguard will expect that the flame is not present. If,
however, the flame existed for a period of >15 seconds,
the flame safeguard will go into permanent lock-out.
Phase 8: Post-purge speed test
Both gas valves are closed during this phase. End call
for heat.
Post-purge occurs during the programmed period.
Phase 9: Additional post-purge
If the fixed high limit trips during normal operation,
the blower will purge for 15 minutes to cool the heat
exchanger.