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S8700B,D-F,J-M DIRECT SPARK IGNITION CONTROLS

69-1299

4

Fig. 3. Typical wiring diagram for 

S8700E,J,L single rod models.

NOTE:

NOTE: Proper system operation requires that 
the S8700 GND (Burner) terminal is wired to 
be electrically common with the spark 
electrode bracket, flame sensor bracket (if a 
separate flame sensor is used) and the main 
burner. In many applications, this is 
accomplished through connecting the S8700 
GND (Burner) terminal to the appliance 
chassis, as the other noted components are 
presumed to be electrically common with the 
appliance chassis. If flame sensing problems 
are noted, it may be due to corroded or loose 
electrical connections between the noted 
components and the appliance chassis.  

STARTUP 

The following start-up procedures are basic to all S8700 
controls. 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 can differ, refer to the 
manufacturer’s instructions for start-up and checkout 
procedures for other system components.

NOTE:

If the S8700 does not perform as outlined in 
the following Start System and Check Trial for 
Ignition steps, refer to the Service section to 
determine the cause.

Gas Leak Test

If the gas control has been replaced as a part of the S8700 
installation, perform the following test for gas leaks.

WARNING

Explosion or Fire Hazard. 
Gas Leaks can cause property damage, 
severe injury or death.
To avoid possible explosion or fire, perform the 
Gas Leak Test.

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 a leak, tighten the 
joints and screws. Never use a flame to check for gas 
leaks.

Start System

1.

Turn on the power and the gas supply.

2.

Set the temperature control to call for heat and 
watch for a spark at the igniter (S8700B,D,E,F 
models have no delay on start-up; S8700J,K,L,M 
models have a predetermined delay on start-up 
for prepurge).Check that the system starts as 
follows: Prepurge delay (if provided), spark turns 
on, gas valve opens at once and burner ignites 
after gas reaches the main burner. Once the 
burner flame is established, spark igniter cuts off.

NOTE:

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).

Table 3. S8700 Trial for Ignition Periods.

Check Trial for Ignition

1.

Check device label on the control to determine 
the 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 S8700 and 
immediately start timing when the gas valve is 
energized.

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 5.

5.

After spark cutoff, manually reopen the gas sup-
ply cock. No gas should flow to the main burner.

6.

Reset the system as described in Resetting 
S8700 After Safety Lockout section.

Q347
SPARK
IGNITER

BURNER

IGNITER AND
BURNER GROUND

L1 
(HOT)
L2

1

2

3

1

2

3

POWER SUPPLY. PROVIDE DISCONNECT MEANS 
AND OVERLOAD PROTECTION AS REQUIRED.

ALTERNATE LIMIT CONTROLLER LOCATION.

MAXIMUM IGNITER-SENSOR CABLE LENGTH: 6 FT (1.8 M).

S8700E,J,L CONTROL

ANY COMBINATION
GAS CONTROL
2.0A MAX.

TEMPERATURE
CONTOL

LIMIT CONTROLLER

TRANSFORMER

M16528

FLAME
SENSE

ALARM

VALVE

GND

VALVE (GND)
24 Vac (GND)
24 Vac

BURNER

(GND)

SPARK

ALARM, IF USED

Specified Trial for 

Ignition (TFI) (stamped 

on control)

Trial for Ignition Should 

Not Exceed

4.6 sec

5.0 sec

6.6 sec

7.0 sec

11.1 sec

11.5 sec

21.1 sec

21.5 sec

Summary of Contents for S8700 Series

Page 1: ...tput is positive phase one half wave rectified 24 Vac Spark Output 14 KV minimum into 25 picofarad capacitive load Environmental Ambient Operating Temperature 40 F to 175 F 40 C to 79 C Relative Humidity 5 to 95 at 95 F 35 C noncondensing Ignition Sequence Flame Sense Prepurge See Table 1 Ignition Trials to Lockout See Table 1 Trial for Ignition Times 4 6 6 6 11 1 or 21 1 second nominal available ...

Page 2: ... to protect the control Proper insulation or shielding should be provided by the appliance manufacturer verify proper air circulation is maintained when the appliance is installed System Requirements S8700 system requirements Q347A Spark Igniter and Q354A Flame Sensor or a Q366 with separate spark igniter and flame sensor mounted on a common bracket Equivalent ignition hardware may be used Honeywe...

Page 3: ...ontrol 1 Connect the system components to the S8700 terminals as shown in the wiring diagrams Fig 2 and 3 Refer to the heating appliance manufac turer s instructions for wiring any other auxiliary controls 2 Adjust the temperature control heat anticipator if provided to match the system current draw The current draw equals the total current required for the S8700 0 15A plus the gas valve and all o...

Page 4: ...t System 1 Turn on the power and the gas supply 2 Set the temperature control to call for heat and watch for a spark at the igniter S8700B D E F models have no delay on start up S8700J K L M models have a predetermined delay on start up for prepurge Check that the system starts as follows Prepurge delay if provided spark turns on gas valve opens at once and burner ignites after gas reaches the mai...

Page 5: ...the reset normal condition and interrupts the spark ignition circuit Should the current flow be interrupted i e flame out condition the spark will be re initiated immediately and a normal trial for ignition will occur If the main burner lights and proves a normal run will occur If the main burner does not light and prove the S8700 goes into lockout The S8700 keeps the gas control main valve open a...

Page 6: ...gnition circuit do the following 1 Shut off the gas supply to the gas control 2 Be sure system power supply delivers proper volt age to the S8700 during the ignition cycle 3 Disconnect the ignition cable at the S8700 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 Fig 4 S8700B D J K one ...

Page 7: ...y even though operation is normal at time of checkout Therefore if nuisance shutdowns have been reported be sure to check ground connections Electrical ground connections at the spark igniter or igniter sensor and the S8700 must be clean and tight If leadwire is damaged or deteriorated use only a No 14 or No 18 gauge moisture resistant thermoplastic insulated wire with 221 F 105 C minimum rating a...

Page 8: ...ions as described in the following sections Fig 6 S8700D F K M dual rod flame current measurement Fig 7 S7800B E J L single rod flame current measurement Burner Flame The flame sensor must be constantly immersed in flame Check the burner flame conditions as shown in Fig 7 NOTE Note If the main burner flame is fluctuating or lifting off the main burner intermittent flame signals can be generated Ad...

Page 9: ...ce or repair the troubleshooting sequence should be repeated until normal system operation is obtained NOTE When the appliance is in the lightoff mode ignition spark and the gas control are energized only during the trial for ignition which can last from four to 21 seconds depending on the S8700 model It will be necessary to recycle the call for heat to the control while performing this troublesho...

Page 10: ...SPARK GAP IS NOT TOO SMALL OR TOO LARGE ALL OK REPAIR REPLACE AS NECESSARY REPAIR REPLACE AS NECESSARY IF S8700 GOES INTO LOCKOUT RESET SYSTEM CHECK FOR 24 VAC BETWEEN S8700 VALVE AND VALVE GND TERMINALS DURING TRIAL FOR IGNITION CHECK GAS SUPPLY GAS CONTROL AND GAS CONTROL WIRING REPAIR REPLACE AS NECESSARY IF S8700 GOES INTO LOCKOUT RESET SYSTEM CHECK ALL IGNITION CABLE BURNER GROUND WIRING AND ...

Page 11: ...11 69 1299 ...

Page 12: ...Home and Building Control Honeywell Inc Honeywell Limited Honeywell Limitée Honeywell Plaza 155 Gordon Baker Road P O Box 524 North York Ontario Minneapolis MN 55408 0524 M2H 3N7 Printed in U S A on recycled paper containing at least 10 post consumer paper fibers ...

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