Additional Information
Call for heat
Flame signal
Ignition
Combination
gas valve
Actual fan
speed
Fan required
signal
Modulation
range
Time (sec)
Pre-ignition timing
(factory-set)
Pre-purge
Safety timing
Post-purge
time
Ignition load
if flame exists after gas
valve closure
Post-purge
Stabilization period
max.
51 sec
max. 51
sec
factory set
0.3
sec
factory set to
max. 4.9 sec
max. 30 sec
factory set
max. 51
sec
-
-
-
70
Burner Program Sequence of Operation
Flame safeguard program sequence of operation
Phase
Explanation
0
Stand by
1
Stand-still status
test
2
Pre-purge speed
test
3
Pre-purge
4
Pre-ignition
5
Ignition
6
Burner in operation:
controller active
7
Proof of closure
test / gas valve
8
Post-purge speed
test
9
Post-purge
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
The air proving switch is tested first
using the programmed ignition blower
speed. After the air proving switch
test, the pre-purge speed (or the forced
pre-purge speed) will be controlled
within a
¦
300 rpm tolerance in a 51
second period.
Phase 3: Pre-purge
Pre-purge cycle starts within the
pre-programmed timing. If air proving
switch opens during this period, the
burner will revert back to Phase 1.
Also, if at the end of the pre-purge
period expected blower speed is not
reached, the burner will revert back to
Phase 1.
Phase 4: Pre-ignition
The ignition spark is initiated and
controlled.
Phase 5: Ignition
The gas valve opens during the safety
timing period (4.8 secs.). If a flame is
detected, this phase ends immediately
in < 4.8 secs. If the flame is not
established after 3 trials, the burner
will lock out and will require a manual
reset.
Phase 6: Burner operation
At the end of the flame stabilization
period (10 sec.), a release for
modulation occurs and the burner
temperature controller will take over
from the flame safeguard.
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 >30 seconds,
the flame safeguard will go into
permanent lock-out.
Phase 8: Post-purge speed test
Both gas valves are closed during this
phase.
Phase 9: Post-purge
Post-purge occurs during the
programmed period. If the fixed high
limit trips during normal operation, the
blower will purge for 10 min. to cool
the heat exchanger.
5
5
8
1
7
7
5
1
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