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Terminal 21 holds the system indefinitely at the end of low fire start. When opened (off) terminal 21
starts pilot trial for ignition. If the countdown method is set, at the end of a low fire start period the
display indicates:
HOLD 00:00
T21 INPUT
During the AUTO or RUN position, terminal 21 is used to force the firing motor to the low fire position.
In this state the display indicates:
HOLD T21 42 top line indicates hold mode with
flame signal LOW FIRE SIGNAL
Terminal 16 holds the system in a pilot proving state following the pilot trial for ignition period. After
pilot trial for ignition, as determined by the PTFI*MTFI TIMING selection, terminal 5 is de-energized
and terminal 6 remains energized. During this state, the system is in a flame proven state. The display
indicates:
PILOT 42 flame signal displayed
T16 INPUT pilot hold period
Once terminal 16 is released (or de-activated), the Burnerlogix proceeds to the MTFI period in
accordance with the PTFI*MTFI TIMINGS selection. If selected, terminal 5 with the ignitor energizes
during MTFI.
Terminal 16 is also used to revert the system back to the pilot proving mode from the AUTO or RUN
mode. During AUTO, an active state on terminal 16 starts the steps to revert back to pilot mode. On
detection of terminal 16, the firing rate motor is commanded to the low fire position and the system waits
for the low fire start switch (M-D) to close. While in this wait mode the display indicates:
HOLD T16 42 while in AUTO, Terminal 16 closes.
M-D LIMIT OPEN wait for low fire interlock to close.
Once the low fire start switch is detected as closed, terminal 6 is energized to open the pilot valve and
terminal 5 is energized to power the ignition transformer. A 20 second time delay is then imposed.
with both the main valve (7) and pilot valve (6) energized. The display indicates:
HOLD T16 42 while in AUTO, M-D detected closed.
M-D LOW LIMIT wait 20 seconds in this state.
At the end of the 20 seconds, the main valve (7) is de-energized, and the ignition terminal (5) remains
energized for the time specified in PTFI*MTFI TIMINGS. Terminal W is energized for 5 seconds. The
display indicates:
PTFI 42 flame signal displayed.
FLAME SIGNAL
Unlike PTFI, this period is a flame proven state and if flame signal is lost for one FFRT, the system
shuts down and locks out. At the end of the selected PTFI time, terminal 5 is de-energized and the
Burnerlogix proceeds to the pilot proving period with terminal 6 energized and flame being proven. The
display indicates:
PILOT 42 flame signal displayed.
T16 INPUT pilot hold period.
Note: When the main fuel valve is de-energized, its proof-of-closure switch (Fuel Valve End Switch) is
expected to close between terminals L1 and 13. If the L1-13 circuit does not close by the time terminal
5 is de-energized, the control will shut down and display: "LOCKOUT PILOT, T13 FVES OPEN"
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