Johnson Controls G77 Series Installation Sheets Manual page 5

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Start
Thermostat
call for heat
Prepurge
Trial for
ignition
Pilot
flame
sensed?
No
Maximum
No
number of trials
Interpurge
attempted?
Ignition lockout
(optional LED
flashes)
Recycle delay
period
Figure 2: G77x Sequence of Operation
Flame present when
not expected
Flame
No
Yes
present for
30 seconds?
Yes
Energize
main valve
Yes
Control with
No
ignition
recycle?
Yes
Shutoff
GG77x Intermittent Pilot Ignition Controls Technical Bulletin
Detected fault
Hard Lockout
(optional LED
turns off)
Run
No
Flameout?
Yes
Yes
Sixteenth
flameout?
No
Yes
Thermostat
calling for heat?
No
De-energize
control and valves
End
5