Gas Pilot Ignition Adjustment; Pilot Spark Ignition Electrode Adjustment - Power Flame C Series Installation & Operation Manual

Gas Pilot Ignition Adjustment

Excessive gas pressure and insufficient air may be
the most common causes of pilot ignition failure.
Burners with automatic air dampers linked to the gas
valve or damper motor should have pilot gas pressures
as follows:
C1-0 (Gas Pilot) C1-GO-10, C1-GO-12
With Std. #36 Orifice
With 7" Fan & #30 Pilot Orifice
C2-OA (Gas Pilot) C2-G(O))-15
C2-OB (Gas Pilot) C2-G(O)-20A(B)
C3-O (Gas Pilot) C3-G(O)-20, C3-G(O)-25
C4-O (Gas Pilot) C4-G(O)-25,C4-G(O)-30
C5-O(B) (Gas Pilot) C5-G(O)-30, C5-G(O)-30B
C6-O (Gas Pilot) C6-G(O)-30
C7-O(B) (Gas Pilot) C7-G(O)-30, C7-G(O)-30B
C8-O (Gas Pilot) C8-G(O)-30
Fixed fire (on-off) burners with manually adjustable
dampers may need slightly higher pressures, but in any
event do not increase pressure beyond that required for
a stable flame signal. Gas pressure should be read at
the test tee on the pilot gas supply pipe with a
manometer or 0-10" W.C. gauge. Look for stability of gas
pressure at all times. For burners equipped with auto-
matic air dampers (linked to the gas valve or damper
motor), there is a tendency to set the air dampers in a
closed, barely open position. This action may produce
insufficient air for dependable pilot ignition. Air damper
openings should be at least
on one, with the other nearly closed. Some job conditions
or heat exchangers may require larger air damper
openings or different gas pressures than those shown
above. For dependable pilot ignition, always use air
damper setting to provide MOST air and LOWEST pilot
gas pressure setting allowable for good pilot signal at all
times. On fixed fire (on-off) burners the manually adjust-
able air damper setting will need to match air for
Figure 39
Pilot Case to Gas Manifold Adjustment
Inner Tube
Baffle
Orifice Ring
Pilot Body
Scanner Pipe
Intermediate Tube

Pilot Spark Ignition Electrode Adjustment

The arc from the electrode tip should jump from the tip to
the body of pilot housing and should be lined up with the
hole in the backside of pilot housing, so that the blower
air passing through this hole will cause the arc
to flag or move around. Normal spark gap should be
2 1 / " - 3 1 / " W.C.
2 2
1 1
1 / " - 2 / " W.C.
2 2
2" - 4" W.C.
1
1 / "-3" W.C.
2
1 1 / "-2" W.C.
2
1 1 / "-2" W.C.
2
1 1 / "-2" W.C.
2
1 1 / "-3" W.C.
2
2-4" W.C.
2-4" W.C.
1 / " on each damper or 1 / "
4 2
No Air Gap
proper CO setting. The following steps should be taken:
2
1. Remove pilot assembly and check for proper orifice
size (the orifice size is stamped into the hex brass
fitting connected to the pilot head nozzle assembly)
and spark gap. The spark gap between the electrode
and the outside radius of the gas pilot assembly
1 3
should be / " - / ". Do not set spark to arc against
16 32
the pilot head nozzle. See page 40, Figures 40 and 41.
2. Close checking cock (test cock). Start up burner and
stop flame safeguard control timer with check
switch during pilot ignition. Access to check
switch on Fireye D Series is best obtained by using
a small right angle tool, such as an Allen Wrench.
If there is no check switch, disconnect wire which
energizes main automatic gas valve, so that air
damper is not actuated.
3. Observe pilot signal with DC voltmeter or micro-
ammeter and reduce pilot gas pressure to a point
where the signal is erratic or reduced substantially
from initial reading.
4. Raise the pilot gas pressure to the point where the
signal is again stable. Remove scanner and use a
mirror to view the pilot flame through the scanner
pipe (a live flame from cigarette lighter or butane
torch may be needed to keep scanner actuated).
Be sure to get full coverage of scanner pipe by pilot
flame.
Release check switch or reconnect main automatic
gas valve (see step #2) and observe meter as main
gas valve opens and moves air damper. If there is a
drop in signal as this happens, increase pilot pressure
slightly until signal is steady at all times.
Refer to page 40, Gas Pilot Flood Test as another
means of determining proper pilot fuel/air mixture.
Refer to item 13, page 26 for Spark Pickup Test.
Pilot case to gas manifold adjustment is very
important. As depicted, the inside radius of the pilot
body must be tight against the outside radius of the
gas manifold.
The bottom of the pilot body must also be tight
against the notched portion of the baffle ring, just
slightly above the scanner pipe. If there is an air
gap between the pilot body and the gas manifold
and/or the baffle ring, the resulting air flow may
prevent the pilot flame from being swept downward
across the scanner pipe.
1 3
/ " - / ". Electrode should not be moved so far
16 32
forward that the pilot flame will impinge on the
porcelain insulator. This condition will cause the
porcelain to crack and break off at the point of flame
impingement.
C39
Rev.304