Honeywell S8701 - Manual (Page 7)

69-1174 7
S8701/S8702 DIRECT SPARK IGNITION CONTROLS
Fig. 5. S8701/S8702 Sequence of Operation for Retry Models (E, F, L and M Models).
SERVICE
IMPORTANT
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
manufacturer’s service instructions.
Preliminary Check
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.
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.
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.
START
PREPURGE
(L AND M MODELS ONLY)
SAFE START CHECK
TRIAL FOR IGNITION
MAIN BURNER
OPERATION
END
THERMOSTAT CALLS FOR HEAT
SAFE START CHECK. LED BLINKS RAPIDLY.
PREPURGE - L & M MODELS ONLY
INTERPURGE
SPARK GENERATOR POWERED
MAIN VALVE OPERATORS OPEN.
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.
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:
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.
MAIN BURNER OPERATION
UNIT MONITORS BURNER
FLAME CURRENT.
LOSS OF FLAME
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.
M18057
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
DURING NORMAL OPERATION LED BLINKS ONCE PER SECOND.