resideo S8910U User manual

INSTALLATION INSTRUCTIONS
69-0845-03
S8910U Universal Hot Surface
Ignition Module
Installation Instructions for the Trained Service
Technician.
APPLICATION
The S8910U Universal Hot Surface Ignition Module is
designed to provide easy field replacement for a wide
range of hot surface ignition modules manufactured by
Resideo, Robertshaw and White-Rodgers. The S8910U
Module provides operating control of a direct ignition
system using a 120 Vac hot surface igniter. The S8910U
replaces existing flame rectification type hot surface
ignition modules with the following characteristics:
• 120 Vac (up to 5A) timed warmup hot surface ignition
elements.
• Single rod (local sense) or dual rod (remote sense)
hot surface ignition.
• One or three ignition trials per call for heat.
• Four-second or seven-second ignition trials.
• Prepurge of 32 seconds or less.
• Up to 96 seconds between trial purge times (three-
trial mode only).
• Natural or LP gas.
The S8910U is not designed to replace:
• Intermittent pilot ignition controls.
• Direct spark ignition controls.
• Proven 120 Vac hot surface ignition controls.
• 24 Vac element hot surface ignition controls.
• 240 Vac input/120 Vac element hot surface ignition
controls.
• 120 Vac timed warmup hot surface ignition controls
with:
— Ignition trial time shorter than four seconds.
— Ignition trial time longer than twelve seconds.
— Edge connectors rather than male quick-con-
nects.
The S8910U package contains the S8910U control, and
easy-to-use instructions, and the accessories required
to adapt the existing hot surface ignition module. The
accessory bag assembly includes the White-Rodgers
adapter, Robertshaw ground lead, four 1/4 in. female
.032 quick-connects, one 3/16 in. female .032 quick-
connect, four selection tabs and seven wire labels. The
wiring labels are included to assure proper marking of
the wires attached to the existing module.
A complete list of the specific Resideo and other
modules that the S8910U is designed to replace is
provided in Table 1 through 3.
NOTE: The S8910U is intended to replace only defec-
tive ignition controls. The service technician
should make sure that the other parts of the
appliance and control system operate safely
and reliably before replacing the ignition con-
trol.
WARNING
EXPLOSION HAZARD. CAN CAUSE INJURY OR
EQUIPMENT DAMAGE.
The S8910U can only be used for direct replace-
ment. Check Table 1 through 3 before replacing
an existing hot surface module with the S8910U.
If the existing module is not listed, do not use the
S8910U to replace it. Always use the selection
tab specified in Table 1 through 3 for the existing
module being replaced. Replacing with an
unlisted module or using a selection tab not
specified can result in appliance malfunction.
Electrical Ratings:
Control Voltage: 24V, 60 Hz.
Maximum Valve Contact Rating: 2A. Current Draw:
.4A plus valve load.
Hot Surface Igniter Voltage: 120 Vac, 60 Hz. Contact
Rating At 120 Vac: 5A.
IMPORTANT
Use the S8910U only in a 60 Hz system. Be
sure the system is not 50 Hz.
Hot Surface Igniter or Igniter-Sensor:
Norton Model 201 or 271 or equivalent.
NOTE: If an igniter other than a Norton Model 201 or
271is used, the igniter must meet the following
minimum specifications required over the life
of the igniter:
— Igniter must reach 1832 °F (1000 °C) within
34 seconds with 102 Vac applied.
— Igniter must maintain at least 500M ohms
insulation resistance between the igniter
leadwires and the igniter mounting bracket.
— Igniter must not develop an insulating layer
on its surface (over time) that would prevent
flame sensing.
— Igniter surface area immersed in flame must
not exceed one-fourth of the grounded area
immersed in flame. This would prevent
flame sensing.

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
69-0845—03 2
— Igniter current draw at 132 Vac must not
exceed 5A.
Sensor:
A separate sensor is required for remote sensing appli-
cations.
Wiring:
Use the existing appliance wiring. If repair or replace-
ment of leadwires is required, follow the instructions
on the appliance label. Use the included quick-con-
nect terminals according to the instructions.
Prepurge:
32 seconds.
Igniter Warmup:
34 seconds.
Between Trial Purge:
96 seconds (three trial mode only).
Flame Failure Response Time:
1.5 seconds maximum.
Ignition Sequence:
The number of trials for ignition and trial time are deter-
mined by the selection tab. See Table 1. If a selection
tab is not installed, the module will operate at four
seconds trial time and one ignition trial.
Ambient Operating Temperature:
-40 °F to +175 °F (-40 °C to +79 °C).
Accessory Bag Assembly:
• White-Rodgers adapter.
• Robertshaw ground lead.
• Four 1/4 in. female .032 quick-connects.
• One 3/16 in. female .032 quick-connect.
• Four selection tabs.
• Seven wire labels.
Approval Bodies:
IAS Design Certified: Certification Report No. C2027002.
Table 1. White-Rodgers Control to Resideo S8910U Cross Reference.
NOTE: This list is for reference only. Resideo reserves the right to add or delete models at any time, based on new or
updated information.
White-Rodgers product information was obtained from the 1991 White-Rodgers Product Catalog (R3700).
Model Numbers
S8910U Local (L)
or Remote
(R)
Sensing
Lockout
Time
(sec)
Ignition
Trials
PrePurge
(sec)
Igniter
Warmup
(sec)
Between
Trial Purge
(sec)
Selection
Tab
Remove
Black
Jumper
S8910U
Specifications
A
—
Local or
Remote
4
1
32 34
NA
B396
C
7
1NA
D396
50E47-1thru9AYesR41017NA
50E47-10thru19AYesR41045NA
50E47-20 thru 29 A Yes R 4 1 30 17 NA
50E47-30 thru 39 A Yes R 4 1 30 45 NA
50E47-40 thru 49 B Yes R 4 3 30 17 90
50E47-50 thru 59 B Yes R 4 3 30 45 90
50E47-60thru69BYesR4301760
50E47-70thru79BYesR4304560
50E47-101 thru 109 C Yes R 71017NA
50E47-110 thru 119 C Yes R 71045NA
50E47-120 thru 129 C Yes R 7 1 30 17 NA
50E47-130 thru 139 C Yes R 7 1 30 45 NA
50E47-140 thru 149 D Yes R 7 3 30 17 90
50E47-150 thru 159 D Yes R 7 3 30 45 90
50E47-160 thru 169 D Yes R 7301760
50E47-170 thru 179 D Yes R 7304560
50E47-201 thru 209 A Yes R 41017NA
50E47-210 thru 219 A Yes R 41045NA
50E47-220 thru 229 A Yes R 4 1 30 17 NA
50E47-230 thru 239 A Yes R 4 1 30 45 NA
50E47-240 thru 249 B Yes R 4 3 30 17 90
50E47-250 thru 259 B Yes R 4 3 30 45 90
50E47-260 thru 269 B Yes R 4301760
50E47-270 thru 279 B Yes R 4304560
50E47-301 thru 309 C Yes R 71017NA

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
369-0845—03
50E47-310 thru 319 C Yes R 71045NA
50E47-320 thru 329 C Yes R 7 1 30 17 NA
50E47-330 thru 339 C Yes R 7 1 30 45 NA
50E47-340 thru 349 D Yes R 7 3 30 17 90
50E47-350 thru 359 D Yes R 7 3 30 45 90
50E47-360 thru 369 D Yes R 7301760
50E47-370 thru 379 D Yes R 7304560
50F47-1thru9AYesR41017NA
50F47-10thru19AYesR41045NA
50F47-20 thru 29 A Yes R 4 1 17 17 NA
50F47-30 thru 39 A Yes R 4 1 17 45 NA
50F47-40 thru 49 B Yes R 4 3 17 17 77
50F47-50 thru 59 B Yes R 4 3 17 45 77
50F47-60thru69BYesR4301760
50F47-70thru79BYesR4304560
50F47-101 thru 109 C Yes R 71017NA
50F47-110 thru 119 C Yes R 71045NA
50F47-120 thru 129 C Yes R 7 1 17 17 NA
50F47-130 thru 139 C Yes R 7 1 17 45 NA
50F47-140 thru 149 D Yes R 7 3 17 17 77
50F47-150 thru 159 D Yes R 7 3 17 45 77
50F47-160 thru 169 D Yes R 7301760
50F47-170 thru 179 D Yes R 7304560
50F47-201 thru 209 A Yes R 41017NA
50F47-210 thru 219 A Yes R 41045NA
50F47-220 thru 229 A Yes R 4 1 17 17 NA
50F47-230 thru 239 A Yes R 4 1 17 45 NA
50F47-240 thru 249 B Yes R 4 3 17 17 77
50F47-250 thru 259 B Yes R 4 3 17 45 77
50F47-260 thru 269 B Yes R 4301760
50F47-270 thru 279 B Yes R 4304560
50F47-301 thru 309 C Yes R 71017NA
50F47-310 thru 319 C Yes R 71045NA
50F47-320 thru 329 C Yes R 7 1 17 17 NA
50F47-330 thru 339 C Yes R 7 1 17 45 NA
50F47-340 thru 349 D Yes R 7 3 17 17 77
50F47-350 thru 359 D Yes R 7 3 17 45 77
50F47-360 thru 369 D Yes R 7301760
50F47-370 thru 379 D Yes R 7304560
Table 1. White-Rodgers Control to Resideo S8910U Cross Reference.
NOTE: This list is for reference only. Resideo reserves the right to add or delete models at any time, based on new or
updated information.
White-Rodgers product information was obtained from the 1991 White-Rodgers Product Catalog (R3700).
Model Numbers
S8910U Local (L)
or Remote
(R)
Sensing
Lockout
Time
(sec)
Ignition
Trials
PrePurge
(sec)
Igniter
Warmup
(sec)
Between
Trial Purge
(sec)
Selection
Tab
Remove
Black
Jumper
S8910U
Specifications
A
—
Local or
Remote
4
1
32 34
NA
B396
C
7
1NA
D396

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
69-0845—03 4
aThe S8910U and the original control lockout times are different. The S8910U lockout time is within the design toler-
ance lockout time of the original control.
bThe lockout time of the S8910U is shorter than the original control. Be sure to observe the appliance operation under
a variety of input conditions to assure reliable operation.
Table 2. Robertshaw Control to Resideo S8910U Cross Reference.
NOTE: Robertshaw product information was obtained from the 1993-1994 Robertshaw Uni-Line Catalog (2–064).
Model Numbers
S8910U Local (L)
or Remote
(R)
Sensing
Lockout
Time
(sec)
Ignition
Trials
PrePurge
(sec)
Igniter
Warmup
(sec)
Between
Trial Purge
(sec)
Selection
Tab
Remove
Black
Jumper
S8910U
Specifications
A
—
Local or
Remote
4
1
32 34
NA
B396
C
7
1NA
D396
HS780-17NL-104A A No L 41017NA
HS780-17NL-108A C No L 8a1017NA
HS780-17NL-304A B No L 4301717
HS780-17NL-308A D No L 8a301717
HS780-17NR-104A A Yes R 41017NA
HS780-17NR-306A D Yes R 6a301717
HS780-17NR-308A D Yes R 8a301717
HS780-34NL-108A C No L 8a1034NA
HS780-34NL-304A B No L 4303434
HS780-34NL-306A D No L 6a303434
HS780-34NL-308A D No L 8a303434
HS780-34NL-312A D No L 12b303434
HS780-34NR-104A A Yes R 41034NA
HS780-34NR-306A D Yes R 6a303434
HS780-34NR-308A D Yes R 8a303434
HS780-34NR-312A D Yes R 12b303434
HS780-34PL-308A D No L 8a3 343434
Table 3. Resideo Control to Resideo S8910U Cross Reference.
Model Numbers
S8910U Local (L)
or Remote
(R)
Sensing
Lockout
Time
(sec)
Ignition
Trials
PrePurge
(sec)
Igniter
Warmup
(sec)
Between
Trial Purge
(sec)
Selection
Tab
Remove
Black
Jumper
S8910U
Specifications
A
—
Local or
Remote
4
1
32 34
NA
B396
C
7
1NA
D396
S89C1004 C No L 6a1034NA
S89C1012 C No L 6a1034NA
S89C1046 ANoL41034NA
S89C1087 C No L 6a1034NA
S89C1103 ANoL41034NA
S89D1002 C Yes R 6a1034NA
S89G1005 BNoL4303430
S89G1013 D No L 6a303430
S89G1021 D No L 11b303430
S89G1047 D No L 6a 3 0 34 30

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
569-0845—03
aThe S8910U and the original control lockout times are different. The S8910U lockout time is within the design toler-
ance lockout time of the original control.
bThe lockout time of the S8910U is shorter than the original control. Be sure to observe the appliance operation under
a variety of input conditions to assure reliable operation.
REVIEW THE INSTALLATION
WARNING
FIRE OR EXPLOSION HAZARD. CAN CAUSE
PROPERTY DAMAGE, SEVERE INJURY, OR
DEATH.
Follow these warnings exactly:
1. Review the installation as outlined in this
section.
2. Plan for frequent maintenance as described in
the Maintenance section.
When hot surface ignition systems are used on central
heating equipment in barns, greenhouses, and
commercial properties and on heating appliances such
as commercial cookers, agricultural equipment,
industrial heating equipment and pool heaters, heavy
demands are made on the controls. Special steps can be
required to prevent nuisance shutdowns and control
failure due to frequent cycling, severe environmental
conditions related to moisture, corrosive chemicals, dust
or excessive heat. These applications require Resideo
Home and Building Control Engineering review; contact
your Resideo Sales Representative for assistance.
Review the following conditions that can apply to your
specific installation and take the precautionary steps
suggested.
Frequent Cycling
These controls are designed for use on appliances that
typically cycle only three to four times an hour during the
heating season. In year-round applications with greater
cycling rates, the control can wear out more quickly.
Perform a monthly checkout.
Water or Steam Cleaning
If a module or gas control gets wet, replace it. If the
appliance is likely to be cleaned with water or steam,
cover the controls and wiring to protect from water or
steam flow.
Mount the controls high enough above the bottom of the
cabinet to avoid getting wet during normal cleaning
procedures. NEMA 4 enclosure is recommended for the
ignition module; see the Electronic Ignition Service
Manual, form 70-6604.
High Humidity or Dripping Water
Dripping water can cause the module to fail. Never install
an appliance where water can drip on the controls.
In addition, high ambient humidity can cause the gas
control to corrode and fail.
If the appliance is in a humid atmosphere, make sure air
circulation around the controls is adequate to prevent
condensation. Also, regularly check out the system.
NEMA 4 enclosure is recommended for the ignition
module; see the Electronic Ignition Service Manual, form
70-6604.
S89H1003 BYesR4303430
S89H1011 D Yes R 6a303430
S89H1029 D Yes R 11b303430
S89J1008 C No L 6a1034NA
S890C1007 C No L 6a1 3034NA
S890D1006 C Yes R 6a1 3034NA
S890G1003 B No L 4 3 30 34 30
S890G1011 D No L 6a3 303430
S890G1029 D No L 11b3 303430
S890G1037 D No L 6a3 303430
S890H1002 B Yes R 4 3 30 34 30
S890H1010 D Yes R 6a3 303430
S890H1028 D Yes R 11b3 303430
Table 3. Resideo Control to Resideo S8910U Cross Reference.
Model Numbers
S8910U Local (L)
or Remote
(R)
Sensing
Lockout
Time
(sec)
Ignition
Trials
PrePurge
(sec)
Igniter
Warmup
(sec)
Between
Trial Purge
(sec)
Selection
Tab
Remove
Black
Jumper
S8910U
Specifications
A
—
Local or
Remote
4
1
32 34
NA
B396
C
7
1NA
D396

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
69-0845—03 6
Corrosive Chemicals
Corrosive chemicals can attack the module and gas
control, eventually causing a failure. If chemicals are
used for routine cleaning, avoid contact with the controls.
Where chemicals are suspended in air, for some
industrial or agricultural applications, a NEMA 4
enclosure is recom-mended for the ignition module; see
the Electronic Ignition Service Manual, form 70-6604.
Dust or Grease Accumulation
Heavy accumulations of dust or grease can cause
controls to malfunction. Where dust or grease can be a
problem, provide covers for the module and the gas
control to limit contamination. A NEMA 4 enclosure is
recommended for the ignition module; see the Electronic
Ignition Service Man-ual, form 70-6604.
Heat
Excessively high temperatures can damage controls.
Make sure the maximum ambient temperature at the
control does not exceed the rating of the control. If the
appliance operates at very high temperatures, use
insulation, shielding, and air circulation as necessary to
protect the controls. Proper insulation or shielding
should be provided by the appliance manufacturer; verify
proper air circulation is maintained when the appliance is
in-stalled.
INSTALLATION
When Installing this Ignition
System...
1. Read these instructions carefully. Failure to follow
them could damage the components or cause a
hazardous condition.
2. Check Table 1 through 3 to confirm that the
S8910U is a direct replacement for the existing
module.
3. Installer must be a trained, experienced service
technician.
4. After installation is complete, check out compo-
nent and appliance operation as provided in these
instructions.
WARNING
FIRE OR EXPLOSION HAZARD CAN CAUSE
PROPERTY DAMAGE, SEVERE INJURY, OR
DEATH.
1. If the ignition module gets wet, it can
malfunction, leading to accumulation of
explosive gas.
• Never install where water can flood, drip or
condense on the module.
• Never use a module that has been wet.
Replace it.
2. Liquefied petroleum (LP) gas is heavier than air
and will not vent upward naturally.
• Do not light the pilot or operate electric
switches, lights or appliances until you are
sure the appliance area is free of gas.
3. Do not attempt to disassemble or clean the
module. Improper reassembly and cleaning
can cause unreliable operation.
CAUTION
1. Disconnect the power supply before beginning
wiring to prevent electrical shock or equipment
damage.
2. If a new gas control is to be installed, turn off
the gas supply before starting the installation.
After the gas control is installed, conduct a Gas
Leak Test according to the gas control
manufacturer instructions.
3. If a module must be mounted where it can be
exposed to moisture or water, provide a
suitable waterproof enclosure.
4. Using the wire labels provided, label all the
wires before disconnecting. Wiring errors can
cause improper appliance operation and
dangerous conditions such as bypassing
safety features.
Perform Preinstallation Safety
Inspection
A preinstallation safety check of the appliance and
venting system must be done before the replacement
module is installed. If a condition is detected that could
result in unsafe operation, shut off the appliance and
advise the owner of the unsafe condition. Correct any
potentially unsafe condition before proceeding with the
installation.
Remove Old Module
Disconnect the power supply before doing any work on
the unit. Disconnect and tag the wires from the old
module using the wire labels provided. Remove the old
module from its mounting location.
Mount New Ignition Module
Mount the S8910U Module in the same location as the
old module. Protect the module from exposure to water,
moisture, corrosive chemicals and excessive dust and
grease. Assure that ambient temperature at the module
is within the range listed in the Application section.
Mount the module with the terminals down to protect
from dripping water and dust. The module can also be
mounted with terminals on either side. Do not mount
with the terminals pointing up. Refer to Fig. 1 for
mounting recom-mendations. When it is necessary to
drill new mounting holes, use the S8910U as a template
to mark the mounting hole pattern. Drill new holes as
required. Fasten securely with four No. 6-32 machine or
No. 8 sheet metal screws.
Install Selection Tab
Four selection tabs are included with the S8910U. See
Table 1 through 3. Select the correct tab for the system
and separate the tab from the other three tabs. Install the
tab on the module. Be sure the selection tab is properly
positioned and firmly inserted. See Fig. 2. Discard all
unused selection tabs at a remote location so an
incorrect tab cannot be used in the future. Without a
selection tab, the module operates at four-second trial
time and one ignition trial.

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
769-0845—03
Fig. 1. Module mounting recommendations.
WARNING
EXPLOSION HAZARD. CAN CAUSE INJURY OR
EQUIPMENT DAMAGE.
Only trained professional gas appliance service
technicians should install and check out the
S8910U and selection tabs. Use only the
selection tab specified in Table 1 through 3 for
the existing module being replaced. Always
remove all unused selection tabs from the job site
and discard them at a remote location. Improper
use of the selection tabs can result in appliance
malfunction.
Fig. 2. Separating and installing selection tab.
Wire the Module
CAUTION
1. Check the wiring diagram furnished by the
appliance manufacturer, if available, and
compare with Table 4. Carefully follow any
special instructions affecting the general
procedures outlined in this section.
2. Disconnect the power supply before making
wiring connections to prevent electrical shock
or equipment damage.
IMPORTANT
1. All wiring must comply with applicable electrical
codes and ordinances.
2. Hot surface igniter leadwires should not be
allowed to rest against grounded metal sur-
faces.
3. A common ground is required for the S8910U
and the main burner. The 24V (GND) terminal
internally grounds one side of the transformer.
Any auxiliary controls or limits must not be in
the grounded leg. In addition, the appliance
should be earth-grounded.
4. Make sure the transformer has adequate VA.
The ignition module requires 0.4A at 24 Vac.
Add the current draws of all other devices in the
control circuit, including the pilot and main
valves in the gas control, and multiply by 24 to
determine the total VA requirement of these
components. Add this total to 9.6 VA (for the
ignition module). The result is the minimum
transformer VA rating. Use a Class II trans-
former when replacement is required.
5. Check that L1 (hot) and L2 (neutral) are wired to
the proper terminals.
1. Connect the wires to the S8910U Ignition Module
as shown in Table 4. Make sure that adequate sys-
tem ground is provided as indicated in the wiring
table. See Fig. 3 through 5. Where a change in
quick-connect is required, cut off the original
quick-connect, strip the leadwire and firmly crimp
in place the proper quick-connect supplied.
2. Verify the thermostat anticipator setting as
explained in the preceding IMPORTANT, item 4.
TERMINALS FACING DOWN
TERMINALS FACING LEFT TERMINALS FACING RIGHT
MOUNT IN ONE OF THESE POSITIONS
DO NOT MOUNT
WITH TERMINALS FACING UP
M2647
M8434
S8910U
HOT SURFACE
IGNITION CONTROL
SELECTION TAB
(A)(B) (C)(D)

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
69-0845—03 8
aRemove quick-connect and replace with the included 1/4 in. quick-connect.
bUse green adapter cable (provided) to connect S8910U GND (BURNER) terminal to chassis ground.
cDo not use the S8910U VALVE (GND) terminal. VALVE (GND) and 24V (GND) are interconnected in the appliance wir-
ing.
dRemove quick-connect and replace with the included 3/16 in. quick-connect.
eDo not use this terminal if model being replaced does not have 120V neutral power supply connection.
fUse the black wire on the included adapter cable.
gUse the orange wire on the included adapter cable.
hOn remote sense models, remove jumper quick-connect from S8910U sense terminal, cut jumper wire at circuit
board and discard. On local sense models, leave black jumper connected.
iRemove jumper from S8910U sense terminal, cut jumper wire at circuit board and discard.
Table 4. Replacement Wiring Terminals.
Terminal Function
Replacement Control Original Control
S8910U Terminal
Resideo
S89/S890 Terminal
White Rodgers
50E/F47 Terminal
Robertshaw
HS780 Terminal
Burner Ground Connection GND (BURNER) GND (BURNER)aGND TR (GND CLIP)b
Tranformer Secondary
(unswitched leg)
24V (GND) 24V (GND)aTR GND
Main Valve Common VALVE (GND) VALVE (GND)aMVa(next to TR terminal) —c
Transformer Secondary
(switched leg)
24V 24VaTH TH
Main Valve Operator VALVE VALVE MVdVALVEd
120 Vac Neutral Leg Power
Supply L2 120V NEUTRALeL2 120V NEUTRAL — L2
120 Vac Hot Leg Power
Supply
L1 120V HOT L1 120V HOT LfL1
Hot Surface Igniter Element HSI 120V NEUTRALeHSI 120V — IGN
Hot Surface Igniter Element HSI 120V HOT HSI 120V IGNgIGN
Flame Sensor SENSEhSENhFPiRSh

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
969-0845—03
Fig. 3. Typical hookup when S8910U replaces White-Rodgers 50E/F47.
MV
MV
L1
(HOT)
L2
1
2
1
2
3
4
4
5
4
6
3
COMBINATION
GAS CONTROL
S8910U HOT SURFACE IGNITER CONTROL
HOT
SURFACE
IGNITER
FLAME
SENSOR
LIMIT
CONTROLLER
THERMOSTAT OR
CONTROLLER
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
MAKE SURE L1 AND L2 ARE NOT REVERSED.
ALTERNATE LIMIT CONTROLLER LOCATION.
REMOVE JUMPER QUICK-CONNECT FROM S8910U. CUT WIRE AT CIRCUIT BOARD AND DISCARD.
USE ADAPTER PLUG WITH BLACK AND ORANGE WIRES (SUPPLIED).
CUT 3/16 IN. QUICK-CONNECT OFF WIRE AND REPLACE WITH 1/4 IN. QUICK-CONNECT (SUPPLIED).
CUT 3/16 IN. QUICK-CONNECT OFF WIRE AND REPLACE WITH 3/16 IN. QUICK-CONNECT (SUPPLIED).
BURNER
GROUND
M8528C
AUTOIGN ITION
SYSTEMS
ANSI Z21.20
STATUS LED:
1.Flash-Ignition Lockout
2Flash-Weak Flame Signal
3Flash-Internal Error-Replace Control
Pulsing "Heartbeat"-Normal Operation
S8910U HO T SURFACE IGNITIO N
INPUT VOLTAGES = 120 & 24 VAC, 60HZ
HSI = 120V, 6.5A MAX
VALVE = 24V, 1A MAX TOTAL 24V LOAD = 0.2 + VALVE LOAD
120VAC
HOT
6
5
0
0
A
0
7
5
WARNING
!
Explosion hazard. Can cause
serious injuryor death.
This device can malfunction if
it gets wet. Never try to use a
device that has been wet -- replace it.
DNG
)RENRUB(
V42
)
D
N
G
(
EVL
A
V
)
D
N
G(
V42
DE
L
2
L
ISH
1
L
ISH
E
SNES
EVLAV
SEE
INSTRUCTIONS
FOR REMOTE
SENSE/DUAL
ROD
APPLICATION S
TRIAL TIME,
NUM. OF TRIALS
CONFIGURATION
PLUG
120VAC
NEUTRAL
Prepurge Time = 30 Sec
Igniter Warmup Time = 34 sec
ADAPTER
ORANGE
BLACK
6
TERMINAL CROSS
REFERENCE
S8910U
GND(BURNER)
24V (GND)
VALVE (GND)
24V
VALVE
L2
L1
HSI
HSI
SENSE
50E/F47
GND
TR
MV
(NEXT TO TR)
TH
MV
—
L
—
IGN
FP
5
4
4

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
69-0845—03 10
Fig. 4. Typical hookup when S8910U replaces Robertshaw HS780.
MV
MV
L1
(HOT)
L2
1
3
2
1
2
3
4
4
5
6
COMBINATION
GAS CONTROL
S8910U HOT SURFACE IGNITER CONTROL
HOT
SURFACE
IGNITER
FLAME
SENSOR
LIMIT
CONTROLLER
THERMOSTAT OR
CONTROLLER
1POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
MAKE SURE L1 AND L2 ARE NOT REVERSED.
ALTERNATE LIMIT CONTROLLER LOCATION.
SENSE ROD WILL BE PRESENT IF REMOTE SENSE HS780 MODEL. SEE TABLE 3.
WHEN HS780 IS A REMOTE SENSE MODEL, REMOVE JUMPER QUICK-CONNECT FROM S8910U. CUT WIRE AT CIRCUIT
BOARD AND DISCARD. CONNECT FLAME ROD LEAD WIRE TO SENSE. SEE TABLE 2.
CUT 1/4 IN. QUICK-CONNECT OFF WIRE AND REPLACE WITH 3/16 IN. QUICK-CONNECT (SUPPLIED).
USE GREEN GROUND ADAPTER (SUPPLIED) TO CONNECT S8910U GND (BURNER) TO APPLIANCE CHASSIS.
BURNER
GROUND
M8529C
AUTOIGN ITION
SYSTEMS
ANSI Z21.20
STATUS LED:
1. Flash-Ignition Lockout
2 Flash-Weak FlameSignal
3 Flash-Internal Error-Replace Control
Pulsing "Heartbeat"-Normal Operation
S8910U HOT SURFACE IGNITIO N
INPUT VOLTAGES = 120 & 24 VAC, 60HZ
HSI = 120V, 6.5A MAX
VALVE = 24V, 1A MAX TOTAL 24V LOAD = 0.2 + VALVE LOAD
120VAC
HOT
6
5
0
0
A
0
7
5
WARNING
!
Explosion hazard. Can cause
serious injury or death.
This device can malfunction if
it gets wet. Never try to use a
device that has been wet -- replace it.
D
N
G
)RENR
UB(
V42
)
D
N
G
(
EV
L
A
V
)
D
N
G
(
V42
DEL
2L
ISH
1L
ISH
ESNES
EVL
AV
SEE
INSTRUCTIONS
FOR REMOTE
SENSE/DUAL
ROD
APPLICA TIONS
TRIA LTIME,
NUM. OF TRIALS
CONFIGURA TION
PLUG
120VAC
NEUTRAL
Prepurge Time = 30 Sec
Igniter Warmup Time = 34 sec
5
6
4
HS780
TR (GND CLIP)
GND
—
TH
VALVE
L2
L1
IGN
IGN
RS
4
4
TERMINAL CROSS
REFERENCE
S8910U
GND(BURNER)
24V (GND)
VALVE (GND)
24V
VALVE
L2
L1
HSI
HSI
SENSE
6

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
11 69-0845—03
Fig. 5. Typical hookup when S8910U replaces Resideo S89/S890.
STARTUP AND CHECKOUT
Check out the gas control system:
• At initial installation of the appliance.
• As part of regular maintenance procedures.
• At maintenance intervals determined by the
application.
• As the first step in troubleshooting.
• Any time work is done on the system.
Maintenance frequency must be determined individually
for each application; see Maintenance section.
WARNING
FIRE OR EXPLOSION HAZARD
CAN CAUSE PROPERTY DAMAGE, SEVERE
INJURY, OR DEATH.
1. If you smell gas or suspect a gas leak, turn off
gas at the manual service valve and evacuate
the building. Do not try to light any appliance;
do not touch any electrical switch or telephone
in the building until you are sure no spilled gas
remains.
2. Gas leak test must be done as described in
following steps 1 and 6 for initial installation
and any time work is done involving the gas
piping.
STEP 1: PERFORM VISUAL INSPECTION.
a. With power off, make sure all wiring connec-
tions are clean and tight.
b. Turn on the power to the appliance and the
S8910U.
c. Open the manual shutoff valves in the gas line
to the appliance.
d. Test for a gas leak upstream of the gas control
if piping has been disturbed.
GAS LEAK TEST: Paint the gas control gasket edges and
all the pipe connections upstream of the gas control with
a rich soap and water solution. Bubbles indicate gas
leaks. Tighten the joints and screws or replace the
component to stop a gas leak. Recheck with soap and
water solution.
STEP 2: VERIFY CONTROL SYSTEM GROUND.
The ignition module must share a common ground with
the main burner. The burner serves as the common
grounding area to assure reliable flame detection. If there
is not good metal-to-metal contact between the burner
and ground, run a lead from the burner to ground.
STEP 3: REVIEW NORMAL OPERATING SEQUENCE AND
MODULE SPECIFICATIONS. SEE “OPERATION” ON
PAGE 12 AND “APPLICATION” ON PAGE 1.
STEP 4: RESET THE IGNITION MODULE.
a. Turn the thermostat or controller to the lowest
setting.
b. Turn on the system power.
c. Wait one minute.
MV
MV
L1
(HOT)
L2
1
3
2
1
2
3
4
4
5
COMBINATION
GAS CONTROL
S8910U HOT SURFACE IGNITER CONTROL
HOT
SURFACE
IGNITER
FLAME
SENSOR
LIMIT
CONTROLLER
THERMOSTAT OR
CONTROLLER
1POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
MAKE SURE L1 AND L2 ARE NOT REVERSED.
ALTERNATE LIMIT CONTROLLER LOCATION.
SENSE ROD WILL BE PRESENT IF REMOTE SENSE S89/S890 MODEL. SEE TABLE 3.
WHEN S89/S890 IS A REMOTE SENSE MODEL, REMOVE JUMPER QUICK-CONNECT FROM S8910U. CUT WIRE AT CIRCUIT
BOARD AND DISCARD. CONNECT FLAME ROD LEAD WIRE TO SENSE. SEE TABLE 3.
CUT QUICK-CONNECTS OFF WIRES AND REPLACE WITH 1/4 IN. QUICK-CONNECTS (PROVIDED).
BURNER
GROUND
M8530C
AUTOIGNITION
SYSTEM S
ANSI Z21.20
STATUS LED:
1. Flash-Ignition Lockout
2 Flash-Weak Flame Signal
3 Flash-Internal Error-Replace Control
Pulsing "Heartbeat"-Normal Operation
S8910U HO T SURFACE IG NITION
INPUT VOLTAGES = 120 & 24 VAC, 60HZ
HSI = 120V, 6.5A MAX
VALVE = 24V, 1A MAX TOTAL 24V LOAD= 0.2 + VALVE LOAD
120VAC
HOT
6
5
0
0
A
0
7
5
WARNING
!
Explosion hazard. Can cause
serious injury or death.
This device can malfunction if
it getswet. Nevertry to use a
device that has been wet-- replace it.
DNG
)
R
E
N
R
U
B(
V42
)
D
N
G
(
EV
LAV
)
D
N
G(
V42
DE
L
2L
IS
H
1L
I
S
H
ESN
ES
EVL
AV
SEE
INSTRUCTIONS
FOR REMOTE
SENSE/DUAL
ROD
APPLICATIONS
TRIAL TIME,
NUM. OF TRIA LS
CONFIGU RATION
PLUG
120VAC
NEUTRAL
Prepurge Time= 30 Sec
Igniter Warmup Time = 34 sec
5 5 5 5
4
S89/S890
GND (BURNER)
24V (GND)
VALVE (GND)
24V
VALVE
L2
L1
HSI
HSI
SEN
TERMINAL CROSS
REFERENCE
S8910U
GND(BURNER)
24V (GND)
VALVE (GND)
24V
VALVE
L2
L1
HSI
HSI
SENSE

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
69-0845—03 12
As you do Steps 5 and 6, watch for points where
operation deviates from normal. Refer to
“Troubleshooting” on page 14 to correct problem.
STEP 5: CHECK SAFETY LOCKOUT OPERATION.
a. Turn off the gas supply.
b. Set the thermostat or controller above the room
temperature to call for heat.
c. Watch for igniter warmup following prepurge.
Igniter starts to glow several seconds after it is
powered.
d. Time the length of time the gas control is ener-
gized; measure the time by connecting a volt-
meter across the gas valve terminals:
Selection tabs A and B: 4 seconds.
Selection tabs C and D: 7 seconds.
e. When using a three-trial ignition selection tab
(tabs B or D), watch for the start of 96-second
between-trial purge, followed by 34-second
igniter warmup and second try for ignition.
After a third purge, warmup and trial for ignition
sequence, the S8910U should lock out. LED
goes into one flash mode after lockout.
f. Open the manual gas control knob and make
sure no gas is flowing to the burner.
g. Set the thermostat below the room temperature
and wait one minute before continuing.
STEP 6: CHECK NORMAL OPERATION.
a. Set the thermostat or controller above the room
temperature to call for heat.
b. Observe the lightoff sequence and make sure
the main burner lights smoothly without flash-
back.
c. Make sure the burner operates smoothly with-
out floating, lifting, or flame rollout to the fur-
nace vestibule or heat buildup in the vestibule.
d. Test for a gas leak downstream of the gas con-
trol if piping has been disturbed.
GAS LEAK TEST: Paint the gas control gasket edges and
all pipe connections downstream of the gas control with
a rich soap and water solution. Bubbles indicate a gas
leak. Tighten the joints and screws or replace component
to stop a gas leak. Recheck with soap and water solution.
e. Check the burner flame condition. The igniter-
sensor or sensor must be constantly immersed
in flame. Check the burner flame condition as
shown in Fig. 6. Do not relocate the hot surface
igniter or flame rod.
f. Turn the thermostat or controller below the
room temperature. Make sure the main burner
and pilot flames go out.
WARNING
FIRE OR EXPLOSION HAZARD
CAN CAUSE PROPERTY DAMAGE, SEVERE
INJURY, OR DEATH.
Improper location of the 120 Vac hot surface
igniter or any flame sensing rod can result in
appliance malfunction.
1. Never attempt to relocate the 120 Vac hot
surface igniter or the flame sensing rod from
the original position established by the
appliance manufacturer.
2. Be sure the 120 Vac hot surface igniter or the
flame sensing rod is replaced in exactly the
original position after removal for inspection,
service or replacement.
Fig. 6. Check burner flame condition.
OPERATION
The S8910U is a direct ignition control used with a 120
Vac timed warmup hot surface igniter. The control
provides operating control and shuts off all gas flow on
ignition failure or loss of main burner flame in central
heat furnaces and other heating appliances.
Module operation is in three phases—prepurge/igniter
warmup, trial for ignition and burner operation. The
S8910U provides one or three trials for ignition,
depending on which selection tab is installed. Fig. 7
shows the normal operating sequence.
Purge/Prepurge
When the S8910U is used in a fan-assisted combustion
system, the combustion air blower starts on a call for
heat from the thermostat. On proof of airflow, the air
proving switch closes and energizes the S8910U. When
the S8910U is used in an atmospheric system, the call for
heat energizes the module. In either case, the S8910U
first initiates a 32-second delay to allow system
prepurge.
Igniter Warmup
After prepurge, the S8910U energizes the igniter to start
the igniter warmup. The module energizes the hot
surface igniter for a 34-second warmup period, during
which the gas control is closed.
CHECK BURNER FLAME CONDITION
NOISY
LIFTING
FLAME
BURNER
WAVING
FLAME
SMALL
BLUE
FLAME
LAZY
YELLOW
FLAME
GOOD
RECTIFYING
FLAME
3/4 TO 1 IN. (19 TO 25 MM)
1/4 TO 1/2 IN. (6 TO 13 MM) M8446
CHECK FOR:
• HIGH GAS PRESSURE
• EXCESS PRIMARY AIR
OR DRAFT
CHECK FOR:
• POOR DRAFT
• EXCESS DRAFT
• HIGH VELOCITY OR
SECONDARY AIR
INSTALL SHIELD IF NECESSARY
CHECK FOR:
• CLOGGED PORTS OR
ORIFICE FILTER
• WRONG SIZE ORIFICE
CHECK FOR LACK OF
AIR FROM:
• DIRTY PRIMARY
AIR OPENING
• LARGE PORTS
OR ORIFICES

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
13 69-0845—03
Fig. 7. S8910U normal operating sequence.
Trial for Ignition
At the end of the warmup period, the gas control opens
for the ignition trial time determined by the selection tab.
The hot surface igniter stays powered for an ignition
activation period of one second if the four-second trial
time is used or four seconds if the seven-second trial
time is used. The igniter turns off after the ignition
activation period. Near the end of the ignition trial time,
the flame rectification sensing circuit determines if the
main burner flame is present. If so, the gas control
remains open and the burner operation phase begins.
Burner Operation
When the main burner is lit, a flame rectification circuit is
completed between the flame sensor (igniter on local
sense systems or flame rod on remote sense systems)
and the main burner (burner ground). The S8910U flame
sensing circuit detects the flame current and holds open
the gas control. The main flame is monitored
continuously during the call for heat.
START
PREPURGE/
IGNITER
WARMUP
CALL FOR HEAT (24V
TERMINAL POWERED)
INTERNAL SAFE START
CHECK BEGINS.
FLAME
SIMULATING
FAILURE
SYSTEM WILL
NOT START
PREPURGE
IGNITER WARMS UP
BETWEEN
TRIAL
PURGE
TRIAL FOR
IGNITION
GAS CONTROL OPENS
FOR TIMED TRIAL
FOR IGNITION.
.LOCKOUT OCCURS;
SYSTEM MUST BE
RESET.
GAS
CONTROL
CLOSES
NO
FLAME
IGNITER OFF;
FLAME SENSING BEGINS.
ONE TRIAL
(TABS A
AND C)
LESS
THAN
THREE
ONE TRIAL
(TABS A AND C)
THREE TRIALS
(TABS B AND D)
HOW MANY IGNITION
TRIALS COMPLETED THIS
CALL FOR HEAT?
THREE
LOCKOUT OCCURS;
SYSTEM MUST BE
RESET.
GAS CONTROL CLOSES
(MAIN BURNER OFF).
GAS
CONTROL
CLOSES
THREE TRIALS
(TABS B AND D)
FLAME
FAILURE
GAS CONTROL STAYS
OPEN (MAIN BURNER
RUNS).
MAIN BURNER
OPERATION
END
NO FLAME
SIMULATING
FAILURE
FLAME
PRESENT
M8527A
CALL FOR HEAT
IS SATISFIED.

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
69-0845—03 14
Safety Shutdown
One Trial Selection Tabs (A and C)
If flame is not sensed by the end of the timed trial for
ignition, the gas control closes and the module locks out.
It must be manually reset by removing power or setting
the thermostat below the room temperature for at least
30 seconds.
If the burner lights and flame is proved but goes out
during the run cycle, the gas control closes and the
module initiates a warmup period followed by one trial
for ignition. If flame is not established, the gas control
closes and the module locks out, requiring manual reset.
Three Trial Selection Tabs (B and D)
If flame is not sensed by the end of the first timed trial for
ignition, the gas control closes and the module initiates a
second 96 seconds between trial purge cycle, followed by
igniter warmup and a second trial for ignition. If flame is
not established, the between trial purge, warmup, trial for
ignition cycle is repeated a third time. If flame is still not
established following the third trial, the gas control
closes and the module locks out. It must be manually
reset by removing power or setting the thermostat below
the room temperature for at least 30 seconds.
If the burner goes out during the run cycle, the gas
control closes and the module checks for the number of
ignition trials performed during the current call for heat. If
the number is less than three, the module initiates a
between trial purge, warmup and trial for ignition. After
the third trial during a single call for heat, the module
locks out. The module must be manually reset following
the lockout.
MAINTENANCE
WARNING
FIRE OR EXPLOSION HAZARD
CAN CAUSE PROPERTY DAMAGE, SEVERE
INJURY, OR DEATH.
Do not attempt to take apart the module or to
clean it. Improper assembly and cleaning can
cause unreliable operation.
Regular preventive maintenance is important in
applications that place a heavy load on system controls
such as those used in the commercial cooking and
agricultural and industrial industries because:
• In many such applications, particularly commercial
cooking, the equipment operates 100,000 to 200,000
cycles per year. Such heavy cycling can wear out the
gas control in one to two years.
• Exposure to water, dirt, chemicals and heat can
damage the gas control and shut down the control
system. A NEMA 4 enclosure can reduce exposure to
environmental contaminants. See Electronic Ignition
Service manual, form 70-6604.
The maintenance program should include regular check-
out of the system as outlined in the Startup and
Checkout section, and checkout of the control system as
described in the appliance manufacturer literature.
Maintenance frequency must be determined individually
for each application. Some considerations are:
•Cycling frequency. Appliances that may cycle 20,000
times annually should be checked monthly.
•Intermittent use. Appliances that are used seasonally
should be checked before shutdown and again before
the next use.
•Consequence of unexpected shutdown. Where the
cost of an unexpected shutdown would be high, the
system should be checked more often.
•Dusty, wet, or corrosive environment. Because these
environments can cause the gas control to deteriorate
more rapidly, the system should be checked more
often.
Any control should be replaced if it does not perform
properly on checkout or troubleshooting. In addition,
replace any module if it is wet or looks like it has ever
been wet. Protective enclosures, as described in the
Planning the Installation section, are recommended
regardless of checkout frequency.
TROUBLESHOOTING
IMPORTANT
1. The following service procedures are provided
as a general guide. Follow appliance manufac-
turer service instructions if available.
2. Meter readings between gas control and ignition
module must be taken within the trial for igni-
tion period. Once the ignition module shuts off,
wait for retry or reset at the thermostat.
3. If any component does not function properly,
make sure it is correctly installed and wired
before replacing it.
4. The ignition module cannot be repaired. If it
malfunctions, replace it.
5. Only trained, experienced service technicians
should service hot surface ignition systems.
6. After servicing, verify proper system operation.
Perform the checkout steps in the Startup and Checkout
section as the first step in troubleshooting. Then check
the troubleshooting sequence (Fig. 8) to pinpoint the
cause of the problem.
After troubleshooting, perform the checkout procedure
again to be sure the system is operating normally.
Status LED used to Troubleshoot
The LED can be used to check the appliance status. A
description of the LED signals follows.
IMPORTANT
The LED shows system status for the current
call for heat. When the call for heat is inter-
rupted (thermostat satisfied or system power
switched off), the LED goes off and the status
information is lost.
• Pulsing heartbeat is the normal operating mode
during a call for heat (24V terminal is powered). The
system can be in any of the normal operating modes
including prepurge, warmup, ignition trial, between
trial purge, or normal run.
• One flash indicates the S8910U is in an ignition
lockout mode. The most probable cause is the main
burner failing to light or failure to detect the flame.
Run the appliance through a call for heat and if the
burner does not light, check the:
— gas supply
— input voltage
— hot surface igniter
— gas control
— wiring

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
15 69-0845—03
If the main burner lights, but goes out at the end of
ignition trial, check the:
— igniter/sensor
—flamerod
— burner ground connections— wiring
• Two flashes indicates the flame rectification signal is
weak. The most probable causes are:
— contaminated or mislocated igniter/sensor or
flame rod
— poor flame sense leadwire insulation or connec-
tions
— poor gas pressure
If the flame rectification signal is strong when the
appliance lights, but weak while heat is being delivered,
check for overheating of the igniter/sensor, flame rod
ceramic or flame sense leadwires.
• Three flashes indicate an internal error. The most
probable cause is an S8910U logic failure. Start a new
call for heat and if the three-flash signal returns,
replace the S8910U.
Ignition System Checks
STEP 1: CHECK THE IGNITER WIRE HARNESS. MAKE
SURE:
a. Ignition cable does not run in contact with any
metal surfaces.
b. Connections to the ignition module and to the
igniter or igniter-sensor are clean and tight.
c. Ignition cable provides good electrical continu-
ity.
STEP 2: CHECK THE IGNITION SYSTEM GROUNDING.
NUISANCE SHUTDOWNS ARE OFTEN CAUSED BY A POOR
OR ERRATIC GROUND.
a. A common ground is required for the module,
igniter, flame sensor and main burner.
• Check for good metal-to-metal contact
between the igniter bracket and the main
burner.
• Check the ground path from the GND
(BURNER) terminal on the module to the main
burner. Make sure the connections are clean
and tight. If the wire is damaged or
deteriorated, replace it by following the
appliance manufacturer instructions. A
temporary leadwire connection between the
GND (BURNER) terminal and the main burner
can help confirm a ground path problem.
• Check the temperature at the igniter ceramic
or flame sensor insulator. Excessive tempera-
ture permits leakage to ground. Contact the
appliance manufacturer if the temperature
exceeds the rating of the igniter or sensor.
• If the flame sensor or bracket is bent out of
position, restore to the correct position.
• Replace the igniter and sensor or igniter-
sensor with an identical unit if the insulator is
cracked.
STEP 3: CHECK THE FLAME SENSING CIRCUIT.
a. Make sure the burner flame is capable of pro-
viding a good rectification signal. See Fig. 6.
b. Make sure about 3/4 to 1 in. of the flame sen-
sor or igniter-sensor is continuously immersed
in the flame for the best flame signal. See
Fig. 6.
c. Check for excessive (higher than 1000 °F
[538 °C]) temperature at the ceramic insulator
on the flame sensor. Excessive temperature
can cause a short to ground.
d. Check for a cracked igniter-sensor or a sensor
ceramic insulator, which can cause short to
ground, and replace unit if necessary.
• Make sure the electrical connections are clean
and tight. Replace damaged wire with
moisture-resistant No. 18 wire rated for
continuous duty up to 221 °F (105 °C).
e. If the igniter is other than a Norton 201 or 271,
make sure it meets the following specifica-
tions:
• Igniter must reach 1832 °F (1000 °C) within
34-seconds with 102 Vac applied.
• Igniter must maintain at least 500M ohm
insulation resistance between the igniter
leadwires and the igniter mounting bracket.
• Igniter must not develop an insulating layer on
its surface (over time) that would prevent
flame sensing.
• Igniter surface area immersed in flame must
not exceed one-fourth of the grounded area
immersed in flame. This would prevent flame
sensing.
• Igniter current draw at 132 Vac must not
exceed 5A.

S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
© 2020 Resideo Technologies, Inc. All rights reserved.
This product is manufactured by Resideo Technologies, Inc. and its affiliates.
www.resideo.com
Resideo Technologies, Inc.
1985 Douglas Drive North, Golden Valley, MN 55422
1-800-468-1502
69-0845—03 M.S. Rev. 06-20 | Printed in United States
Fig. 8. S8910U troubleshooting sequence.
CONFIRM THAT 120V HOT LEAD
CONNECTS TO L1, AND 120V NEUTRAL
LEAD CONNECTS TO L2.
M8531A
NO
NO
NO
NO
NO
NO
YES
YES
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
START
TURN THERMOSTAT TO
CALL FOR HEAT
DOES S8910U GET POWER
(24 VAC NOMINAL)?
30 SECOND MINIMUM
PURGE
IGNITER WARMS UP AND
GLOWS RED
REPEAT PROCEDURE UNTIL TROUBLE-FREE OPERATION IS OBTAINED.
SYSTEM RUNS UNTIL CALL
FOR HEAT ENDS
CALL FOR HEAT ENDS,
SYSTEM SHUTS OFF
TROUBLESHOOTING ENDS
•
•
CHECK FOR PROPER TEMPERATURE CONTROLLER OPERATION.
REMOVE VALVE LEAD AT S8910U; IF VALVE CLOSES, RECHECK TEMPERATURE CONTROLLER
AND WIRING; IF NOT, REPLACE GAS CONTROL.
NOTE: IF S8910U GOES INTO LOCKOUT, RESET SYSTEM.
CHECK CONTINUITY OF GROUND WIRE.
NOTE: IF GROUND IS POOR OR ERRATIC, SHUTDOWNS CAN OCCUR OCCASIONALLY
EVEN THOUGH OPERATION IS NORMAL AT THE TIME OF CHECKOUT.
CHECK FOR EXCESSIVE HEAT AT IGNITER OR FLAME ROD CERAMIC BASE
(TEMPERATURE ABOVE 1000°F (538°C) CAUSES SHORT TO GROUND).
IF CHECKS ARE OKAY, REPLACE S8910U MODULE.
NOTE: SYSTEM FAILURE DURING A RUN CYCLE HAS A LOW PROBABILITY OF
BEING THE S8910U.
•
•
•
MAIN BURNER REMAINS
POWERED AND LIT
MAIN BURNER LIGHTS
CHECK FOR 120 VAC ACROSS HOT
SURFACE IGNITER TERMINALS.
NOTE: IF S8910U GOES INTO LOCKOUT, RESET SYSTEM.
CHECK CONTINUITY OF GROUND WIRE AND GROUND PATH FROM MAIN BURNER TO
GND (BURNER) TERMINAL OF S8910U.
CONFIRM THAT 120 VAC HOT LEAD IS CONNECTED TO L1 AND 120 VAC NEUTRAL LEAD
IS CONNECTED TO L2.
CHECK THAT BURNER FLAME COVERS IGNITER/SENSOR OR SENSOR.
CHECK INSULATION ON IGNITER/SENSOR LEADS.
CHECK IGNITER/SENSOR OR FLAME ROD FOR CONTAMINATION OR DAMAGE. REPLACE,
IF NECESSARY.
CHECK INSULATION ON SENSOR LEADS AND CHECK SENSOR POSITION.
IF CHECKS ARE OK, REPLACE S8910U MODULE.
NOTE: SYSTEM FAILURE AFTER MAIN FLAME LIGHTS HAS A LOW PROBABILITY
OF BEING THE S8910U.
•
•
•
•
•
•
CHECK FOR 24 VAC ACROSS VALVE TERMINALS ON S8910U DURING TRIAL FOR IGNITION
TIMING. IF NO VOLTAGE, REPLACE S8910U.
CHECK ELECTRICAL CONNECTIONS BETWEEN S8910U AND GAS CONTROL.
IF OK, REPLACE GAS CONTROL.
CHECK IGNITER POSITION.
CHECK GAS PRESSURE TO MAIN BURNER.
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REPLACE S8910U.
CHECK AND CORRECT WIRING FUSE
OR CIRCUIT BREAKER.
CHECK WIRES TO IGNITER.
IF OK, REPLACE IGNITER.
CHECK AIR PROVING SWITCH.
REPLACE S8910U.
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CHECK LINE VOLTAGE POWER.
CHECK LOW VOLTAGE TRANSFORMER.
CHECK LIMIT CONTROLLER.
CHECK AIR PROVING SWITCH (IF USED).
CHECK THERMOSTAT.
CHECK WIRING.
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NOTE: BEFORE TROUBLESHOOTING, BECOME FAMILIAR WITH STARTUP
AND CHECKOUT PROCEDURES.