+
-
HIGH TEMP
MATERIAL
CSA rated at 2500°F
Steel Cu Flashed
Nickel Plated Steel
Nickel Plated Steel
Alumina
Alumina
Spring Steel
Kanthal APM
Kanthal APM
Kanthal APM
ACCESSORIES
Proper Electrode Location
Proper location of the electrode assembly is important for
optimum system performance. It is recommended that the
electrode assembly be mounted temporarily using clamps or other
suitable means to check the system before permanently mounting
the assembly. The electrode assembly should be located so that
the tips are inside the flame envelope and about 1/2 inch (10 mm)
above the base of the flame. See Figures 3a and 3b.
CAUTIONS:
1.
Ceramic insulators should not be in or close to the flame.
2.
Electrodes should have a gap spacing of 0.125± 0.031 inch
(3.12 ± 0.81 mm). If this spacing is not correct, the assembly
must be replaced or adjusted (see troubleshooting)
3.
Exceeding the temperature limits can cause
nuisance lockouts and premature electrode failure.
4.
Electrodes must be placed where they are not exposed
to the appliance user in normal operation.
Flame Sensing
Flame sensing is achieved using the principal of flame
rectification. Flame rectification relies on the current passing
from ground through the flame to the sense rod. The minimum
flame current necessary to keep the system operating is
1.0 microamperes.
SINGLE SPARK AND SENSE
Figure 3a
REMOTE FLAME SENSE
Figure 3b
ITEM
#
1
2
3
4
5
6
7
8
9
DESCRIPTION
Mounting Bracket
1/4” Q.C. High Voltage Terminal
3/16” Q.C. Flame Sense Terminal
Spark, H.V. Ceramic Tube
Sense Electrode Ceramic Tube
Press Ring
Flame Sense Electrode
Ground Rod
Spark Electrode, High Voltage
STANDARD
MATERIAL
CSA rated at 1800°F
Steel Cu Flashed
Nickel Plated Steel
Nickel Plated Steel
L-3 Steatite
L-3 Steatite
Spring Steel
Kanthal D
Kanthal D
Kanthal D
#
!
1
2
3
4
6
7
5
8
9
TYPICAL SPARK ELECTRODE
WITH INTEGRAL REMOTE FLAME SENSE
Page 4
Series 35-71, 20 VAC Direct Spark Ignition Control
Figure 4
FLAME CURRENT CHECK: SINGLE SPARK & SENSE AND
REMOTE SENSE
To measure flame current, disconnect the input voltage, and attach
the leads from a DC current meter with a microampere range to
FC+ and FC- terminals to the 35-70 flame sense test pins per
Figure 4. Reconnect the input voltage and initiate a
call for heat. After sparking is complete and the flame is
established the meter should read 1.0 microamperes DC or
higher. If meter reads below "0" on the scale, meter leads are
reversed. Disconnect power and reconnect meter leads
for proper polarity.
www.fenwalcontrols.com
1-800-FENWAL-1
