10. Set the air dampers approximately
1
/
4
" open, and with
both pilot and leak test gas cocks closed, open the
main gas cock (to allow the low gas pressure switch,
if supplied, to make its circuit). With the control switch
in the Off position, apply power to the burner through
the main burner disconnect switch. Switch the burner
panel On/Off switch to the On position momentarily
to determine that the blower rotation is correct.
11. Restart the burner. With the pilot gas cock closed,
the burner will go through a blower prepurge period,
after which the gas pilot ignition transformer will be
energized, although no pilot will be established. (At
no time should there be any flame signal reading, nor
should the main gas valve attempt to open.) At the end
of the pilot trial for ignition and blower purge period, the
flame safeguard control should shut the system down
in a safety lock-out mode, requiring manual reset of
the flame safeguard control to restart the burner.
12. Wait three minutes, reset the flame safeguard control
safety switch (restarting the burner) and open the
pilot gas cock. When the blower prepurge period
ends and the burner is energized--if the flame
safeguard control has a time stop/run switch--stop
the timer while the pilot is on and make adjustments
as required. See page 39 for pilot ignition adjust-
ments. If the burner has automatic air damper
operation (dampers moved by the automatic gas
valve or modulating motor) and the Flame Safeguard
control does not have a timer stop/run switch, it will
be necessary to keep the air dampers in the pilot
light off (low air flow) position by temporarily
electrically disconnecting the motorized gas valve
or modulating motor to complete pilot adjustments.
Recycle the burner several times to make certain
pilot operation is reliable.
13. Perform an initial Spark Pickup Test. With the pilot
gas cock closed, the burner will go through a blower
prepurge period, after which the gas pilot ignition
transformer will be energized, although no pilot will
be established. (At no time should there be any flame
signal reading, nor should the main gas valve
attempt to open.) At the end of the pilot trial for
ignition and blower purge period the flame safeguard
control should shut the system down in a safety
lock-out mode, requiring manual reset of the flame
safeguard control to restart the burner. If a flame
signal is detected, verify the flame retention tab and
ignition electrode are properly positioned, per
Figures 33-37 on pages 36 and 37.
14. With pilot adjustments completed, reset the timer switch
to the Run position, which will allow the sequence to
proceed to the automatic gas valve energizing position.
If the motorized gas valve or modulating motor wires
have been disconnected, shut the burner off and
reconnect electrically to allow normal automatic air
damper operation.
15. When the main automatic gas valve begins to open,
slowly open the checking gas cock to light off the main
flame. The main flame should light immediately. If not, it
may be necessary to eliminate air from the main gas line
and/or adjust main gas pressure regulator flow rates.
16. Adjust the burner as necessary to provide smooth
ignition of the main flame. If the flame signal drops
significantly when the main automatic gas valve opens,
slightly increase the pilot gas pressure to attain a stable
flame signal value.
17. For On/Off burners - adjust the main gas pressure
regulator to achieve the proper main flame gas input.
Set and lock the air dampers to provide 8
1
/
2
to 10% CO
2
(Carbon Dioxide) and little or no* CO (Carbon Monoxide).
Make certain the gas pilot operates reliably at the final
fuel/air settings.
18. For Low/High/Off burners - adjust the main gas pressure
regulator in combination with the air damper linkage
operation to achieve 8
1
/
2
to 10% CO
2
(Carbon Dioxide)
and little or no* CO (Carbon Monoxide) at the full high
fire input rate position. Make certain the linkage operates
smoothly and without binding or overtravel of the air
damper stops.
19. For Low/High/Low burners - adjust the main gas pressure
regulator in combination with the air damper linkage
operation to achieve 8
1
/
2
to 10% CO
2
(Carbon Dioxide)
and little or no* CO (Carbon Monoxide) at the full high
fire input rate position. Make certain the linkage operates
smoothly and without binding or overtravel of the air
damper stops. Run burner to the low fire position and
lock motorized gas valve internal low fire adjustment to
a setting that will attain 7 to 9% CO
2
at the desired low
fire input rate.
20. Intermittently operate the burner until the water is warm in
the boiler, or follow specific initial firing recommendations
provided by the heat exchanger manufacturer.
21. See items 32 through 36 in this section for recommended
limit control and other control devices operational
checkout.
*
See note on Page 25.
Burners Designed for Full Modulation Operation
After completing pilot adjustments and other proce-
dures as appropriate in items 1 through 16 above,
proceed with modulating adjustments as follows:
22. Initial adjustments should be made at the low
fire position. All Power Flame burners are factory
tested and adjusted. However, to determine that
the metering butterfly valve is, in fact, in the low
fire position, observe the end of the metering
valve shaft. The slot in the end of the shaft
indicates the position of the valve. When the slot
is in the horizontal position (parallel with the gas
flow direction), the valve is fully open. Refer to
page 22, Figure 27 for linkage adjustment
information and page 22, Figure 28 for adjust-
ment information on the Varicam
TM
characterized
fuel metering system.
23. Turn the burner on and let it advance to the main flame
light off position. Take action as necessary to hold the
linkage at the low fire position by using a manual
potentiometer or electrically disconnecting the modulating
motor. Power Flame burners are tested at the factory and
linkage adjustments for modulation are made at that
time. Note that the factory settings relate to good
operation while firing into open test pits, and therefore
will normally not relate directly to absolute fuel/air ratios
while firing under specific field conditions. It is suggested
that the factory settings be noted and marked on the
linkage prior to proceeding with final adjustment. In this
manner those settings can be restored as initial reference
points, if need be.
24. With the burner in the factory set low fire position, adjust
air and fuel linkage to good fuel/air ratio low fire settings
Rev.304
C26
To Next Page
Loading...
