Honeywell Cooktop S8701 User Manual

S8701/S8702 Direct Spark  
Ignition Controls  
INSTALLATION INSTRUCTIONS  
The S8701 is a single spark, single flame sense, direct  
ignition control that is compatible with dual rod systems.  
APPLICATION  
S8701 and S8702 Direct Spark Ignition Controls are  
designed for use in commercial cooking and other gas  
heating applications which require direct ignition and flame  
safety control of gas burners. S8701/S8702 controls are  
used to ignite the main burner(s), sense the flame and  
control the gas valve in these applications, see Table 1.  
The S8702 is a dual spark, dual flame sense, direct  
ignition control capable of igniting and sensing flame on  
two separate gas burners that are fed by a single gas  
valve. The S8702 is compatible with dual rod systems  
only.  
Table 1. S8701/S8702 Models.  
Model  
S8701D  
S8702D  
S8702F  
S8702K  
S8702M  
Flame Sense  
remote  
Trials for Ignition  
Spark/Sense  
Prepurge  
No  
1
1
1
2
2
2
2
remote  
No  
a
remote  
3
No  
remote  
1
Yes  
a
remote  
3
Yes  
a
S8702 F and M models include an auto-reset from lockout after 1 hour.  
High Humidity or Dripping Water  
Planning the Installation  
Dripping water can cause the control to fail. Never install  
an appliance where water can drip on the control. In  
addition, high ambient humidity can cause the control to  
corrode and fail. If the appliance is in a humid atmosphere,  
make sure air circulation around the control is adequate to  
prevent condensation. Also, regularly check out the  
system.  
WARNING  
Fire or Explosion Hazard.  
Can cause property damage, severe injury,  
or death.  
Follow these warnings exactly:  
1. Plan the installation as outlined below.  
2. Plan for frequent maintenance as described in  
the Maintenance section.  
IMPORTANT  
Always install a splash cover to protect the  
control from water damage.  
Review the following conditions that can apply to your  
specific installation and take the precautionary steps  
suggested.  
Corrosive Chemicals  
Corrosive chemicals can attack the control, eventually  
causing a failure. If chemicals are used for routine  
cleaning, avoid contact with the control. Where chemicals  
are suspended in air, as in some industrial or agricultural  
applications, protect the control with an enclosure.  
Frequent Cycling  
This control is designed for use on commercial cooking  
appliances that typically cycle 400 times a day, year round.  
Perform a monthly checkout.  
Dust or Grease Accumulation  
Water or Steam Cleaning  
Heavy accumulations of dust or grease can cause the  
control to malfunction. Where dust or grease can be a  
problem, provide covers for the control to limit contamina-  
tion.  
If a control gets wet, replace it. If the appliance is likely to  
be cleaned with water or steam, protect (cover) the control  
and wiring from water or steam flow. Mount the control  
high enough above the floor so it does not get wet during  
normal cleaning procedures.  
®U.S. Registered Trademark  
69-1174  
Copyright © 1999 Honeywell Inc. • All Rights Reserved  
 
S8701/S8702 DIRECT SPARK IGNITION CONTROLS  
Table 4. Transformer Ratings for S8701/S8702 and  
Dual Valve Combination Gas Controls.  
Wiring the S8701/S8702 Control  
1. Connect system components to the S8701/S8702  
terminals as shown in the wiring diagrams, Figs. 2  
and 3. Refer to the appliance manufacturer’s  
instructions for wiring any other auxiliary controls.  
Minimum VA  
Rating (24V  
transformer)  
Total Valve  
Current  
(in amperes)  
S8701/S8702  
(in amperes)  
20  
30  
40  
55  
up to 0.6  
0.6 to 1.0  
1.0 to 1.4  
1.4 to 2.0  
0.15  
0.15  
0.15  
0.15  
2. Adjust temperature control heat anticipator to match  
system current draw. The current draw equals the  
total current required for the S8701 or S8702  
(0.15A) plus the gas valve and all other 24 V control  
loads (vent dampers, prepurge relays, etc.). Gas  
valve must be designed for the DSI application.  
Wiring  
NOTE: Use only recommended ignition cable (see  
Table 5) to connect the S8701/S8702 with the  
spark igniter. Cable must not run in continuous  
contact with a metal surface or spark voltage  
will be greatly reduced; use ceramic standoff  
brackets if necessary. Cable length must not  
exceed 6 ft (1.8m).  
General Precautions  
1. Check the wiring diagram furnished by the  
heating appliance manufacturer, if available, for  
circuits different from the ones shown. Carefully  
follow any special instructions affecting the general  
procedures outlined below.  
2. All wiring must comply with applicable electrical  
codes and ordinances.  
3. Disconnect the power supply before wiring to  
prevent electrical shock or equipment damage.  
4. If installing a separate Q345A flame sensor, the  
sensor leadwire should be kept as short as possible  
and should not be allowed to rest against grounded  
metal surfaces.  
5. A common ground is required for the S8701/S8702,  
the spark igniter and the main burner. The 24V  
(GND) terminal does not internally ground the  
transformer. The 24 V (GND) terminal must be  
grounded to the equipment chassis separately. Any  
auxiliary controls or limits must not be in the  
grounded leg.  
LIMIT CONTROLLER  
2
L1  
(HOT)  
1
L2  
TRANSFORMER  
S8701D CONTROL MODULE  
FLAME  
SENSE  
ALARM, IF USED  
GND  
VALVE (GND)  
24 Vac (GND)  
24 Vac  
ALARM  
VALVE  
ANY COMBINATION  
GAS CONTROL  
2.0A MAX.  
6. Ignition cable should not touch any metal surface or  
current carrying wires. It must not be more than 6 ft  
(1.8m) long.  
7. Do not short valve terminals as this may damage the  
temperature controller, the transformer or the  
S8701/S8702.  
BURNER  
(GND)  
SPARK  
Q347  
SPARK  
IGNITER  
Q354 FLAME  
SENSOR  
Table 5. Recommended Ignition Cable.  
3
Temperature  
Rating  
TEMPERATURE  
CONTOLLER  
RMS  
BURNER  
Voltage Rating  
Cable Type  
°F  
482  
°C  
250  
IGNITER AND  
BURNER GROUND  
UL Style 3257  
10,000  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
2
3
ALTERNATE LIMIT CONTROLLER LOCATION.  
MAXIMUM IGNITER-SENSOR CABLE LENGTH: 6 FT. (1.8 M) OR LESS.  
M16232A  
Fig. 2. S8701 Wiring Diagram.  
 
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S8701/S8702 DIRECT SPARK IGNITION CONTROLS  
LIMIT CONTROLLER  
2
3. Fit one end of another ground wire with a female 1/4  
in. quick connect terminal and connect it to the male  
quick connect 24V (GND) terminal on the S8701/  
S8702 control.  
L1  
(HOT)  
L2  
1
TRANSFORMER  
4. Strip the other end of the 24V (GND) wire and fasten  
it to the burner ground.  
S8702D CONTROL MODULE  
5. If used with a separate flame sensor, make sure the  
bracket is connected to the burner ground.  
SENSE 2  
SENSE 1  
NOTE: It is not necessary that the burner is earth  
grounded.  
ALARM, IF USED  
GND  
VALVE (GND)  
24 Vac (GND)  
24 Vac  
ALARM  
VALVE  
ANY COMBINATION  
GAS CONTROL  
2.0A MAX.  
STARTUP AND CHECKOUT  
BURNER  
(GND)  
SPARK 2  
The following start-up and checkout procedures are basic  
to all S8701 and S8702 control modules. If this is a  
replacement application, refer to the specific instructions  
provided by the heating appliance manufacturer (if  
available). Also, since the auxiliary controls used on any  
DSI system may differ, refer to the manufacturer’s  
instructions for start-up and checkout procedures for other  
system components.  
SPARK 1  
Q347  
SPARK  
IGNITER  
Q354 FLAME  
SENSOR  
3
TEMPERATURE  
CONTOLLER  
BURNER  
NOTE: If one of the system components fail, the S8701/  
S8702 will either not operate or it will go into  
safety lockout (depending on the type of failure).  
If the system does not perform as outlined in  
Start System and Check Trial for Ignition steps  
below, refer to the SERVICE section to deter-  
mine the cause.  
IGNITER AND  
BURNER GROUND  
Q354 FLAME  
SENSOR  
Q347 SPARK  
IGNITER  
3
BURNER  
IGNITER AND  
BURNER GROUND  
Gas Leak Test  
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD  
PROTECTION AS REQUIRED.  
If the gas control has been replaced as a part of the S8701  
or S8702 installation, perform the following test for gas  
leaks.  
2
3
ALTERNATE LIMIT CONTROLLER LOCATION.  
MAXIMUM IGNITER-SENSOR CABLE LENGTH: 6 FT. (1.8 M) OR LESS.  
M16267A  
Fig. 3. S8702 Wiring Diagram.  
WARNING  
Fire or Explosion Hazard.  
Can cause property damage, severe injury  
or death.  
Grounding the S8701/S8702 Spark Igniter and  
Main Burner  
To avoid possible explosion or fire, perform Gas  
Leak Test.  
For the system to operate properly, spark igniter, flame  
sensor bracket, the burner (GND) terminal on the 24V  
(GND) terminal, and the S8701/S8702 control must share  
a common ground with the main burner. Use thermoplastic  
insulated wire with a minimum rating of 105°C (221°F) for  
the ground wire; asbestos insulation is not acceptable. If  
necessary, use a shield to protect the wire from radiant  
heat generated by the burner.  
With the main burner in operation, paint the pipe joints and  
valve gasket with a rich soap and water solution. Bubbles  
indicate a gas leak. To stop leak, tighten joints and screws or  
replace the gasket. Never use a flame to check for gas leaks.  
START SYSTEM  
IMPORTANT  
Use moisture resistant 18 AWG wire rated for  
continuous duty up to 105°C (221°F). Connec-  
tions must be clean and tight.  
1. Turn on the power and the gas supply.  
Set the temperature control to request heat and  
watch for a spark at the igniter (S8701D, S8702D  
models have no delay on start-up. S8702K and M  
models have a predetermined delay on start-up for  
prepurge.). Time the length of the spark operation; it  
must be within the Trial for Ignition (TFI) timing  
period (see Table 6).  
Connect the ground wire as follows:  
1. Fit one end of the ground wire with a female 1/4 in.  
quick-connect terminal and connect it to the male  
quick connect GND (Burner) terminal on the S8701/  
S8702 control.  
2. Check that the system starts as follows: Spark turns  
on, gas valve opens at once, and burner ignites after  
gas reaches main burner. Once burner flame is  
established, spark igniter cuts off. For S8702  
models; flame must be established on both burners  
for spark igniters to turn off.  
2. Strip the other end of the GND (Burner) wire and  
fasten it under the igniter bracket mounting screw. If  
necessary, use a shield to protect the wire from  
radiant heat. The burner serves as the common  
grounding area.  
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S8701/S8702 DIRECT SPARK IGNITION CONTROLS  
NOTE: If the gas control has been replaced or serviced,  
lightoff may not be satisfactory until air has been  
purged from the gas line or the gas input and  
combustion air have been adjusted (see  
manufacturer’s instructions).  
Sequence of Operation  
The S8701/S8702 controls perform the following basic  
functions:  
Supplies power to the electronic pulse-generator  
circuit for the spark igniter (14,000 volts, open circuit).  
Allows up to 23.75 seconds (maximum) for ignition  
and 1 or 3 trials before system safety lockout occurs  
(see Table 4).  
Table 6. Trial for Ignition Periods for the S8701/S8702.  
Specified Trial for  
Trial for  
Ignition (TFI) (stamped Ignition Should  
Senses burner flame for safe lighting (2 burners for  
S8702).  
Shuts off spark after burner is lit.  
Model  
on control)  
4.6 sec  
Not Exceed  
5.05 sec  
S8701;  
S8702  
6.6 sec  
7.25 sec  
The S8701 and S8702 are powered by a 24 Vac trans-  
former and activated when the temperature control  
requests heat.  
11.6 sec  
21.6 sec  
12.75 sec  
23.75 sec  
Operation is as follows:  
When the S8701/S8702 control is activated by the  
temperature control’s request for heat, S8701/S8702  
controls perform a safe-start check that determines proper  
operation of the control before beginning the normal  
sequence of operation. Once the Safe Start Check  
operation passes, the control turns on the spark circuit and  
at the same time, the S8701/S8702 opens the gas  
control’s main valves, which allows gas to flow to the main  
burner.  
Check Trial for Ignition  
1. Check device label on control to determine correct  
Trial for Ignition time.  
2. With the system power off and the thermostat or  
temperature control set to call for heat, manually  
shut off the gas supply.  
3. Turn power on to energize the S8701/S8702,  
immediately start timing when the gas valve turns  
on.  
4. Determine the number of seconds to drop-out of the  
gas valve. It should not exceed the trial for ignition  
time shown in Table 6.  
5. After spark cutoff, manually reopen gas supply cock.  
No gas should flow to the main burner.  
6. Reset system as described below.  
Power is supplied to the generator until:  
The main burner(s) lights and the flame sensor  
current reaches 1.0 µA, or  
The ignition activation period ends  
If the main burner lights, a flame sensing circuit is com-  
pleted through the flame to the burner head to ground.  
This current flow sets the Trial for Ignition timer to the reset  
(normal) condition and interrupts the spark ignition circuit  
(flame sense must occur on both burners on a S8702).  
Should the current flow be interrupted, i.e., flame out  
condition, the trial for ignition period begins again.  
Resetting S8701 and S8702 After Safety  
Lockout  
If the control goes into safety lockout, it will remain locked  
out for D and K models, until the system is reset.  
To reset the system:  
The S8701/S8702 will keep the gas control main valve  
open as long as there is a request for heat and flame  
current through the flame sensing circuit. If, however, the  
trial for ignition timing period ends before the main burner  
lights or the flame sensor establishes enough current, the  
system will go into safety lockout or interpurge if the  
control is an F or M model.  
Adjust the temperature control setting to below room  
temperature, wait 5 seconds, and move the temperature  
control setting up to request heat or remove 24V power  
and reapply. Normal ignition should occur as described in  
Start System section.  
NOTE: F and M models have the 3 retry feature for Trial  
for Ignition with 30 second interpurge between  
TFI periods. Safety lockout on the F and M  
models occurs after the 3rd TFI period if flame is  
not sensed. F and M models also automatically  
reset after one (1) hour in lockout.  
When the system goes into safety lockout, power to the  
spark generator is interrupted, the power to the gas valve  
is interrupted and the alarm circuit is completed and the  
LED is steady on. The system will stay locked out until it is  
reset by moving the temperature control setpoint to below  
room temperature, no request for heat, for 5 seconds.  
Then, re-energize the system by moving the temperature  
control setpoint 5°F (3°C) above room temperature. Or,  
remove 24 Vac power to the control then reapply.  
CHECKOUT  
Start the system and observe operation through at least  
one complete cycle to make certain all controls are  
operating safely.  
NOTE: F and M models will automatically reset from  
lockout after one (1) hour.  
 
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S8701/S8702 DIRECT SPARK IGNITION CONTROLS  
START  
THERMOSTAT CALLS FOR HEAT  
SAFE START CHECK. LED BLINKS RAPIDLY.  
SAFE START CHECK  
PREPURGE  
(J AND K MODELS ONLY)  
PREPURGE - J & K MODELS ONLY  
IF NO SPARK, B, D, J, AND K MODELS GO INTO LOCKOUT  
AFTER ONE (1) TRIAL FOR IGNITION PERIOD.  
ALARM CIRCUIT IS ACTIVATED.  
SPARK GENERATOR POWERED  
MAIN VALVE OPERATORS OPEN.  
TRIAL FOR IGNITION  
LED IS ON STEADY. SYSTEM MUST BE RESET.  
IF FLAME CURRENT SENSED:  
(MUST BE SENSED AT BOTH  
BURNERS ON S8702)  
SPARK GENERATOR IS SHUT OFF.  
LOCKOUT TIMER IS RESET.  
IF FLAME CURRENT IS NOT SENSED:  
B, D, J, AND K MODELS GO INTO LOCKOUT  
AFTER ONE (1)TRIAL FOR IGNITION PERIOD.  
LED IN ON. SYSTEM MUST BE RESET.  
LOSS OF FLAME  
MAIN BURNER  
OPERATION  
MAIN BURNER OPERATION  
UNIT MONITORS BURNER  
FLAME CURRENT.  
SPARK GENERATOR IS POWERED.  
B, D, J, AND K MODELS GO INTO LOCKOUT AFTER  
ONE (1) TRIAL FOR IGNITION PERIOD. LED IS ON STEADY.  
SYSTEM MUST BE RESET.  
TEMPERATURE CONTROLLER  
IS SATISFIED.  
POWER TO UNIT IS INTERRUPTED.  
VALVES CLOSE.  
MAIN BURNER(S) ARE OFF.  
DURING NORMAL OPERATION LED BLINKS ONCE PER SECOND.  
END  
NOTES: B, D, J, AND K MODELS GO THROUGH ONE (1) TRIAL FOR IGNITION PERIOD BEFORE LOCKOUT.  
LOCKOUT = VALVE CLOSED PLUS SPARK OFF PLUS ALARM ACTIVATED PLUS LED ON STEADY.  
M18058  
Fig. 4. S8701/S8702 Sequence of Operation for 1 Trial Models (B, D, J, and K Models).  
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S8701/S8702 DIRECT SPARK IGNITION CONTROLS  
START  
THERMOSTAT CALLS FOR HEAT  
SAFE START CHECK  
SAFE START CHECK. LED BLINKS RAPIDLY.  
PREPURGE  
(L AND M MODELS ONLY)  
PREPURGE - L & M MODELS ONLY  
INTERPURGE  
IF NO SPARK, E, F, L, AND M MODELS GO INTO LOCKOUT  
AFTER THREE (3) TRIAL FOR IGNITION PERIODS.  
ALARM CIRCUIT IS ACTIVATED. LED  
IS ON STEADY. SYSTEM WILL AUTOMATICALLY  
RETRY AFTER ONE (1) HOUR.  
TRIAL FOR IGNITION  
SPARK GENERATOR POWERED  
MAIN VALVE OPERATORS OPEN.  
IF FLAME CURRENT IS NOT SENSED:  
SPARK GENERATOR AND MAIN VALVE OFF. GO TO  
INTERPURGE. E, F, L AND M MODELS GO INTO LOCKOUT  
AFTER THREE (3) TRIAL FOR IGNITION PERIODS. SYSTEM  
WILL AUTOMATICALLY RETRY AFTER ONE (1) HOUR.  
LED IS ON STEADY.  
IF FLAME CURRENT SENSED:  
(MUST BE SENSED AT BOTH  
BURNERS ON S8702)  
SPARK GENERATOR IS SHUT OFF.  
LOCKOUT TIMER IS RESET.  
MAIN BURNER  
OPERATION  
LOSS OF FLAME  
MAIN BURNER OPERATION  
UNIT MONITORS BURNER  
FLAME CURRENT.  
SPARK GENERATOR IS POWERED.  
E, F, L, AND M MODELS GO INTO LOCKOUT AFTER THREE (3)  
TRIAL FOR IGNITION PERIODS. LED IS ON STEADY.  
SYSTEM WILL AUTOMATICALLY RETRY AFTER ONE (1) HOUR.  
TEMPERATURE CONTROLLER  
IS SATISFIED.  
POWER TO UNIT IS INTERRUPTED.  
VALVES CLOSE.  
MAIN BURNER(S) ARE OFF.  
DURING NORMAL OPERATION LED BLINKS ONCE PER SECOND.  
END  
NOTES: E, F, L, AND M MODELS GO THROUGH THREE (3) TRIAL FOR IGNITION PERIODS WITH A 30 SECOND INTERPURGE  
PERIOD BETWEEN TRIAL FOR IGNITION PERIODS BEFORE LOCKOUT AND THEN RETRY AUTOMATICALLY  
AFTER ONE (1) HOUR.  
LOCKOUT = VALVE CLOSED PLUS SPARK OFF PLUS ALARM ACTIVATED PLUS LED ON STEADY PLUS  
ONE (1) HOUR AUTO RESET TIMER ACTIVATED  
M18057  
Fig. 5. S8701/S8702 Sequence of Operation for Retry Models (E, F, L and M Models).  
Preliminary Check  
SERVICE  
IMPORTANT  
The following checks should be made before troubleshoot-  
ing the system.  
1. Check for power to the heating appliance and the  
S8701 or S8702. Voltage to the control should be  
between 20.5 and 28.5 Vac when in run mode.  
2. Make certain that the manual shut-off valve in the  
supply line and the gas cock knob on the combina-  
tion gas control valve are open.  
1. Only persons trained and experienced in DSI  
systems should service this equipment.  
2. If a condition exists that causes the S8701 or  
S8702 control to go into safety lockout, meter  
readings must be taken quickly after restart—  
within the Trial-for-Ignition period.  
3. Always de-energize the system for at least 5  
seconds before recycling for further tests.  
4. Always turn off gas supply before performing  
ignition checks.  
5. S8701 and S8702 control cannot be repaired. If  
the troubleshooting procedure indicates a  
malfunction in the S8701 or S8702, it must be  
replaced.  
6. The following service procedures are for the  
S8701/S8702 and basic DSI systems. On all  
installations, refer to the appliance  
3. Make certain that all wiring connections are clean  
and tight.  
4. Make certain that the S8701 or S8702 is not in  
safety lockout. De-energize the system by moving  
the temperature control setpoint below room  
temperature or by removing the 24 Vac power to the  
S8701/S8702 control. Wait at least 5 seconds and  
reenergize the system by moving the thermostat or  
temperature control setpoint 5°F (3°C) above room  
temperature. Return setpoint to normal temperature  
setting or by re-applying 24 Vac power to the S8701/  
S8702 control.  
manufacturer’s service instructions.  
5. Check ceramic insulator on flame sensor, spark  
igniter or igniter/sensor. A cracked insulator will  
allow current to leak to ground. Replace device if  
insulator is cracked.  
 
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7
S8701/S8702 DIRECT SPARK IGNITION CONTROLS  
6. Check the flame sensor and its mounting bracket.  
Correct the position if bent out of shape.  
7. Review the S8701/S8702 normal sequence of  
operation. See START SYSTEM section.  
Flame Sensor Circuit  
The S8701 and S8702 provide ac power to the flame  
sensor which the burner flame rectifies to direct current. If  
the flame signal is less than 1.0 µA dc, the system will  
lockout.  
S8701/S8702 COMPONENT CHECKS  
Spark Ignition Circuit  
Check the flame sensing current from the sensor to the  
S8701/S8702 control as follows:  
The step-up transformer in the S8701/S8702 provides  
spark ignition at 14,000 volts (open circuit). To check the  
spark ignition circuit, proceed as follows:  
1. Shut off gas supply to the gas control.  
2. Disconnect the ignition cable at the S8701 or both  
S8702 spark terminals to isolate the circuit from the  
spark igniter or igniter sensor. Prepare a short  
jumper lead, using heavily insulated wire such as  
ignition cable.  
1. Connect a meter (dc microammeter scale) in series  
with the flame signal wire as shown in figures 4 and  
5. Use the Honeywell W136A test meter or equiva-  
lent. Disconnect the flame sense wire from the  
sense terminal on the control. Connect the red  
(positive) meter lead to the flame sense terminal on  
the control. Connect the black (negative) meter lead  
to the flame sense wire that goes to the flame rod.  
2. Restart the system and read the meter. The flame  
sensor current must be at least 1.0 µA and steady.  
If the reading is less than 1.0 µA or unsteady , see  
LOW OR UNSTEADY FLAME CURRENT section,  
below. If flame is present at sensor and a reading of  
0 µA is obtained, check for a secondary ground  
connection to the 24 V (GND) terminal.  
WARNING  
High Voltage.  
Can cause personal injury or death.  
To prevent electric shock, do not allow fingers to  
touch either the stripped end of the jumper or the  
stud terminal.  
FLAME  
SENSOR  
3. Perform this test immediately upon energizing the  
system, before the S8701 or S8702 goes into  
lockout and interrupts the spark circuit. Touch one  
end jumper firmly to the S8701/S8702 GND  
terminal. Do not remove the existing ground lead.  
Slowly move the other end of the jumper wire toward  
the spark terminal on the control to establish a  
spark. Pull the wire away from the spark terminal  
and note the length of the gap at which spark  
discontinues.  
SENSE  
BURNER  
1.2 µA dc MINIMUM (AND STEADY)  
ALARM  
VALVE  
MULTIPURPOSE  
METER  
(GND)  
4. A spark length of 1/8 inch (3 mm) or more indicates  
satisfactory voltage output. If no arc can be estab-  
lished or the maximum spark is less than 1/8 inch  
(3 mm), and power to the S8701 or S8702 input  
terminals was proved, replace the S8701/S8702.  
SPARK  
BLACK (–)  
RED (+)  
M16236A  
Ignition Cable  
Fig. 6. S8701 Flame Current Measurement.  
Check the electrical continuity of the ignition cable and  
make certain the cable is not in contact with metal  
surfaces. The total cable length should not exceed 6 ft  
(1.8 m). Check connection to the spark terminal on the  
S8701/S8702 and the boot connection to the igniter/  
sensor. Make certain they are clean and tight.  
FLAME  
SENSOR  
SENSE 2  
BURNER  
GND  
Grounding Connections  
1.2 µA dc MINIMUM  
VALVE (GND)  
24 Vac (GND)  
24 Vac  
(AND STEADY)  
A common ground is required for the burner, spark igniter  
or igniter sensor mounting bracket, the 24 Vac (GND)  
terminal and the GND (burner) terminal of the S8701/  
S8702. If ground is poor or erratic, safety shutdown may  
occur occasionally even though operation is normal at time  
of checkout. Therefore, if nuisance shutdowns have been  
reported, be sure to check ground connections.  
MULTIPURPOSE METER  
BURNER  
(GND)  
Electrical ground connections at the spark igniter or igniter  
sensor and the S8701/S8702 must be clean and tight. If  
leadwire is damaged or deteriorated, use only a no. 14 to  
18 gauge, moisture resistant, thermoplastic insulated wire  
with the 105°C (221°F) minimum rating as a replacement.  
BLACK (–)  
RED (+)  
M16268A  
Fig. 7. S8702 Flame Current Measurement.  
(See also S8701 Fig. 4).  
69-1174  
 
8
S8701/S8702 DIRECT SPARK IGNITION CONTROLS  
Low or Unsteady Flame Current  
Checkout After Service  
If the current to the S8701/S8702 is less than 1.0 µA or is  
unsteady, check the burner flame, flame sensor location  
and electrical connections as follows:  
Perform the following steps before leaving the job (de-  
scribed in the CHECKOUT section).  
START SYSTEM  
TRIAL FOR IGNITION PERIOD CHECK  
SAFETY LOCKOUT RESET  
Burner Flame  
Also perform any other checks recommended by the  
heating appliance manufacturer if system components  
other than the S8701 or S8702 were serviced.  
The flame sensor must be constantly immersed in flame.  
Check burner flame conditions as shown in Fig. 8.  
Flame Sensor  
The flame signal is best when about 1 inch. (25 mm) of  
flame rod is immersed in the burner flame. A bent flame  
rod, bent mounting bracket or cracked ceramic insulator  
can affect flame signal. Replace flame sensor if necessary.  
TROUBLESHOOTING GUIDE  
Start the system by setting the thermostat or temperature  
control to call for heat. Observe the system response and  
establish the type of malfunction or deviation from normal  
operation by using the troubleshooting guide. After any  
maintenance or repair, the troubleshooting sequence  
should be repeated until normal system operation is  
obtained.  
Electrical Connections and Shorts  
Connections at the flame sensor must be clean and tight. If  
wiring needs replacement, use moisture resistant no. 18  
AWG wire rated for continuous duty up to 105°C (221°F).  
CHECK BURNER FLAME CONDITION  
NOISY LIFTING FLAME  
CHECK FOR:  
HIGH GAS PRESSURE  
EXCESS PRIMARY AIR  
OR DRAFT  
BURNER  
WAVING FLAME  
CHECK FOR:  
POOR DRAFT  
EXCESS DRAFT  
HIGH VELOCITY OR  
SECONDARY AIR  
INSTALL SHIELD IF NECESSARY.  
SMALL BLUE FLAME  
CHECK FOR:  
CLOGGED PORTS OR  
ORIFICE FILTER  
WRONG SIZE ORIFICE  
LAZY YELLOW FLAME  
CHECK FOR  
LACK OF AIR FROM:  
DIRTY PRIMARY  
AIR OPENING  
LARGE PORTS  
OR ORIFICES  
GOOD RECTIFYING FLAME  
1 IN. (25.4 MM)  
1/4 TO 1/2 IN. (6.4 TO 12.7 MM)  
M18055  
Fig. 8. Check Burner Flame Conditions.  
 
69-1174  
9
S8701/S8702 DIRECT SPARK IGNITION CONTROLS  
NOTE: BEFORE TROUBLESHOOTING, FAMILIARIZE YOURSELF  
START  
WITH THE START-UP AND CHECKOUT PROCEDURE.  
TURN THERMOSTAT TO  
CALL FOR HEAT  
TURN GAS SUPPLY OFF.  
NO  
NO  
CHECK LINE VOLTAGE POWER, LOW VOLTAGE TRANSFORMER, LIMIT CONTROLLERS,  
THERMOSTATS AND WIRING. ALSO, AIR PROVING SWITCH ON PREPURGE  
SYSTEMS (SEE FIGS. 4 AND 5).  
POWER TO UNIT  
(24 VAC NOMINAL)  
YES  
YES  
UNIT LOCKS OUT ON POWER UP. CHECK FOR FLAME AT EACH BURNER. IF FLAME  
IS PRESENT, SHUT OFF GAS SUPPLY AND REPLACE GAS CONTROL. IF NOT, REPLACE  
IGNITION CONTROL.  
SAFE START CHECK OK.  
YES  
NO  
J, K, L, AND M MODELS  
NO PREPURGE DELAY. REPLACE J, K, L, OR M UNIT.  
PREPURGE DELAY.  
YES  
TURN OFF GAS SUPPLY.  
PULL IGNITION LEAD  
AND CHECK SPARK AT  
SPARK TERMINALS.  
NO  
SPARK ACROSS IGNITER OR  
IGNITER/SENSOR GAP.  
NO  
REPLACE UNIT  
SPARK OKAY?  
YES  
YES  
CHECK IGNITION CABLE, BURNER GROUND WIRING, CERAMIC INSULATOR AND GAP,  
AND CORRECT.  
CHECK BOOT OF THE IGNITION CABLE FOR SIGNS OF MELTING OR BUCKLING. TAKE  
PROTECTIVE ACTION TO SHIELD CABLE AND BOOT FROM EXCESSIVE TEMPERATURES.  
NO  
NO  
CHECK FOR 24 VAC ACROSS VALVE AND VALVE TERMINALS DURING TRIAL FOR  
IGNITION PERIOD. IF NO VOLTAGE, REPLACE UNIT.  
Q347, Q354 OR Q366 MAY BE OUT OF POSITION.  
CHECK ELECTRICAL CONNECTIONS BETWEEN UNIT AND GAS CONTROL. IF OKAY,  
REPLACE GAS CONTROL.  
MAIN BURNER(S) LIGHTS  
YES  
NOTE: IF UNIT GOES INTO LOCKOUT, RESET SYSTEM.  
SPARK STOPS WHEN  
BURNER IS LIT  
CHECK CONTINUITY OF SENSOR CABLE(S) AND BURNER GROUND WIRES.  
CHECK THAT BURNER FLAME COVERS ALL ELECTRODES (ON BOTH BURNERS IF S8702).  
CHECK 24V GROUND CONNECTION TO BURNER.  
IF CHECKS ARE OKAY, REPLACE UNIT.  
YES  
NOTE: IF UNIT GOES INTO LOCKOUT, RESET SYSTEM.  
NO  
SYSTEM RUNS UNTIL  
CALL FOR HEAT ENDS  
CHECK CONTINUITY OF SENSOR CABLE(S) AND GROUND WIRES.  
NOTE: IF GROUND IS POOR OR ERRATIC, SHUTDOWNS MAY OCCUR OCCASIONALLY  
EVEN THOUGH OPERATION IS NORMAL AT TIME OF CHECKOUT.  
CHECK FOR EXCESSIVE HEAT AT SENSOR INSULATOR(S)  
(TEMPERATURE ABOVE 1000 °F (538 °C) CAUSES SHORT TO GROUND).  
IF CHECKS ARE OKAY, REPLACE UNIT.  
YES  
NO  
CHECK FOR PROPER TEMPERATURE CONTROLLER OPERATION.  
REMOVE VALVE LEAD AR UNIT; IF VALVE CLOSES, RECHECK TEMPERATURE  
CONTROLLER AND WIRING; IF NOT, REPLACE GAS CONTROL.  
CALL FOR HEAT ENDS:  
SYSTEM SHUTS OFF  
YES  
REPEAT PROCEDURE UNTIL TROUBLE FREE OPERATION IS OBTAINED.  
TROUBLESHOOTING ENDS  
NOTES: B, D, J, AND K MODELS GO THROUGH ONE (1) TRIAL FOR IGNITION PERIOD BEFORE LOCKOUT.  
E, F, L, AND M MODELS GO THROUGH THREE (3) TRIAL FOR IGNITION PERIODS WITH A 30 SECOND  
INTERPURGE PERIOD BETWEEN TRIAL FOR IGNITION PERIODS BEFORE LOCKOUT AND THEN RETRY AUTOMATICALLY  
AFTER ONE (1) HOUR.  
LOCKOUT = VALVE CLOSED PLUS SPARK OFF PLUS ALARM ACTIVATED PLUS LED ON STEADY.  
S8702 MODELS SPARK AND SENSE FLAME ON TWO SEPARATE BURNERS.  
FLAME MUST BE SENSED ON BOTH BURNERS DURING TRIAL FOR IGNITION ON THE UNIT WILL LOCKOUT.  
M18059  
Fig. 9. S8701/S8702 Direct Spark Ignition System Troubleshooting Guide  
69-1174  
 
10  
 
69-1174  
11  
Home and Building Control  
Honeywell Inc.  
Honeywell Plaza  
Home and Building Control  
Honeywell Limited-Honeywell Limitée  
155 Gordon Baker Road  
North York, Ontario  
P.O. Box 524  
Minneapolis, MN 55408-0524  
M2H 3N7  
69-1174 L.C. 4-99 Printed in Mexico  
 

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