28
13 - NORMAL SEQUENCE OF OPERATION
1.
Thermostat actuates on call for heat, completing circuit
to control.
A. Completed circuit to control will energize the vent
damper. The circulator will be energized if the boiler
water temperature is above 125°F
B. When the vent damper is fully open the damper
end switch completes the circuit to ignition system,
ignition takes place.
2.
In event boiler water temperature exceeds high limit
setting on boiler mounted high limit control, power
is interrupted between control system and ignition
system.
13.1 General
Figure 13-1 Blocked Vent Safety Switch, Roll-out
Safety Switch
WARNING
Fire and Asphyxiation hazard. Do not attempt to
place boiler in operation if safety switches shut the
main burner gas off. Contact a qualified service
agency. Failure to follow these instructions could
result in death or serious injury.
A.
Power remains off until boiler water temperature
drops below high limit setting.
B. Circulator continues to operate under this condition
until thermostat is satisfied.
3.
In event the flow of combustion products through boiler
venting system becomes blocked:
A. Blocked vent safety switch shuts main burner gas
off.
B.
If boiler flue-way becomes blocked: flame rollout
safety switch shuts main burner gas off.
See Figure
13-1.
If either of these conditions A or B exist:
Do not attempt to place boiler back into operation.
Contact certified service agency. Do not jumper saftey
switch(s).
For detailed sequence of control, see Appendix A
WARNING
Burn Hazard. View port on burner door may be hot.
Wear personal protection when servicing this boiler.
!
Blocked Vent
Safety Switch
Rollout Switch
Base
Burner
Door
Burners
Gas Valve
Burner
View Port
Igniter
Honeywell
Control
Transformer
Low Water
Cutoff
Flue
Instpection
Cover
PN 240012809, Rev. C [11/15/2020]
