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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.
C. Circulator will activate if temperature is 125°F or
more.
2.
In event the boiler water temperature exceeds high
limit setting on the boiler mounted high limit control,
power is interrupted between control system and
ignition system.
Blocked Vent
Safety Switch
Rollout Switch
Base
Burner
Door
Figure 13-1 Blocked Vent Safety Switch, Roll-out
Safety Switch (Front Panel Removed)
13.1 General
Gas
Valve
Igniter
Burners
Hydrolevel
Control
View Port
WARNING
Burn Hazard. View port on burner door may be hot.
Wear personal protection when servicing this boiler.
!
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.
!
Ignition
Control
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 the
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.
4.
2-Zone Capability: The Hydrostat IC is equipped with
a second zone for use with a 120-volt circulator. This
zone is factory set to function with an indirect water
heater for domestic hot water (DHW). The control
allows the boiler to run up to high limit setting to
satisfy calls from this zone. The control will allow the
Smart DHW Priority feature to prioritize domestic hot
water. The second zone can also be used for a heating
zone – in which case it should not be prioritized. See
Zone 2 settings in the Hydrolevel Manual provided with
your boiler.
If either of these condition A or B exist:
Do not attempt to place boiler back into operation.
Contact certified service agency. Do Not jumper
safety switch(s).
For detailed sequence of control, see Appendix A.
Flue
Inspection
Cover
PN 240012787 Rev. C [11/15/2020]
