Honeywell 1000 Series Instruction Sheet page 25

SYSTEM OPERATION
General
The S4575A, B, P, Q ignition controls can provide hot surface
ignition.
The Hot Surface Igniter (HSI is connected to a floating
winding of a transformer (see fig 41., 42.).
Lock- out reset
The S4575 can be is reset by either depressing the
internal/external reset button (suffix A and B) or by interrupting
the permanent life (suffix P and Q).
NOTE 14.: If during normal use the reset button is pressed,
the gas valves close and the S4575 ignition
control starts a new sequence after releasing the
reset button.
NOTE 15.: If permanent alarm output: neon indicator with
integral resistor >150 kτ Εmax 1 mA)
T
g
T
g
Suffix A and P (see fig. 43.)
When there is a call for heat the HSI starts glowing during
glowing time (T
After the glowing time (T
The igniter ignites gas and resulting flame is detected by the
flame rod.
After flame establishment a predetermined, extended ignition
time can be included.
If flame is not established within the safety time (T
S4575 ignition control locks out.
If the flame is lost during normal run, the S4575 ignition
control repeats start sequence.
Suffix B and Q (see fig. 44.)
As suffix A and suffix P except flame relay contact is closed
after flame detection.
T T
FR g
Fig. 43. Functional diagram S4575A, P
T T
FR g
Fig. 44. Functional diagram S4575B, Q
25
).
g
) the gas valve is switched on.
g
Legend
T
s
Legend
T
s
), the
s
Thermostat
Ignition
Gas valve
Flame rod
Alarm
Thermostat
Ignition
Gas valve
Flame rod
Flame relay contact
Alarm
EN1R- -9161 0006R10- -NE