HydroStat User Guide

5
IGNITION SEQUENCING AND FLAME SAFETY
INITIATING BOILER IGNITION
Lights come on in sequence.
Spill
switch,
flame
roll-out
switch,
etc.
Power
sent to
vent
damper
or
inducer
Confir-
mation
from
vent
damper
or
inducer
Pilot
Flame is
estab-
lished
The HydroStat-IC proves the safety limit devices on the boiler be-
fore igniting the pilot. As each limit is checked, the corresponding
light will turn on indicating the limit is satisfied. If any limits are not
satisfied, the corresponding light will blink and the ignition sequence
will stop. After ignition, the HydroStat-IC continues to monitor the
limit devices, vent damper or air pressure switch, and pilot flame. If
any of these are open or the pilot flame is lost, the main valve is im-
mediately de-energized and the corresponding light will blink.
Power the system and set the thermostat to call for heat. The decimal on lower
right of the temperature display will light indicating the HydroStat-IC is receiving
the call for heat. Note: The HydroStat HI-TEMP, LOW WATER, and TARGET
lights must all be off for the startup sequence to continue. If any are on, review
page 8 for more information.
1. Limit Check: The control will check all limits in the burner circuit (ex. spill switch, flame roll out switch)
prior to ignition. If all limits are satisfied, the LIMITS light will turn on and the control will proceed to check
the venting. If any limit device is not satisfied, the LIMITS light will blink and the control will not proceed
with ignition.
2. Venting Check:
• 4200a Control: Once the limits are confirmed, the control sends power to the vent damper and the
green V-PWR light comes on. When the vent damper fully opens and triggers the end switch on the
damper, the V-SW light comes on. Note: If the damper end switch does not make within 30 seconds,
the green V-SW light will blink. The startup sequence will stop until the damper end switch makes and
the green V-SW light comes on.
• 4200i Control: Once the limits are confirmed, the control sends power to the inducer motor and the
green V-PWR light comes on. When the inducer motor triggers the air pressure switch, the green V-
SW light comes on. Note: If the air pressure switch does not make within five seconds, the green V-
SW light will blink. The startup sequence will stop until the air pressure switch makes and the green
V-SW light comes on.
Carbon Monoxide Hazard: If the burner fires when the vent damper is not fully opened (at-
mospheric boilers), the inducer fan is not operating (induced draft boilers) or there is any
other blockage in the flue, dangerous flue products, such as carbon monoxide, will escape
into the living space causing severe personal injury or death. The flue as well as the vent
damper or inducer motor must be checked for proper operation before allowing the system
to operate.
Decimal lights on a call for heat
Initiating Boiler Ignition continued next page