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Additional Information
Burner Program Sequence of Operation
Flame safeguard program sequence of operation
Call for heat
Flame signal
Ignition
Combination
gas valve
Actual fan
speed
Fan required
Pre-purge
signal
Modulation
range
max.
Time (sec)
-
51 sec
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.
70
Pre-ignition timing
(factory-set)
Safety timing
Ignition load
factory set
max. 51
0.3
factory set to
sec
max. 4.9 sec
sec
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.
Stabilization period
max. 30 sec
-
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.
if flame exists after gas
valve closure
Post-purge
time
Post-purge
max. 51
factory set
sec
-
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