Honeywell A4021 Series - Page 7

Heat demand
Line voltage
Lock--out
(Ignition controller)
Reset ign. control.
power--up start
heat--demand
end
heat--demand
lock--outstart
heat--demand
reset
burner controller
Leak test
GPS
Valve V1
Vent valve
(normally open)
Valve V2
Leak test
GPS
Valve V1
Vent valve
(normally open)
Valve V2
PRE
POST
CONFIG
CONFIG
start whithout valve proving !
Fig. 6. System sequence of A4021A in post and pre--configuration.
6 EN2R--9023 9705R0--N
E