Ignition Menu - Bradford White OmniTech BONH1250 Installation And Operation Instructions Manual

Page 102
9.D.2

Ignition Menu

The settings in the ignition tab allow the ignition characteristics of the boiler to be customized to fit the boiler
application if needed. In most cases customization will not be necessary. The ignition graph shown is a
representation of how the gas valve will react during the trial for ignition process. In the graph position 3 is the
normal operating combustion level for the boiler at the ignition fan speed. Valve positions below position 3 indicate
that the boiler combustion will be lean during ignition. Valve positions higher than position 3 indicate combustion
will be rich during ignition.
Ramp offset – defines the starting position of the valve during the ignition period. Sets the amount of valve steps
below the learned position the valve starts from during the ignition process. This can be used to start from a lean
starting point if needed.
Ramp period – the amount of time it takes the valve to open through the ramp offset. This can be used to fast or
slow open the valve to tune the ignition if pulsing occurs at ignition.
Hold on period – during the hold on period the gas valve will not make adjustments based on feedback from the
system. This allows the system to stabilize after ignition before the valve starts to make adjustments.
Ignition period – The ignition period must be set to 4 seconds to match the actual ignition period of the boiler
control. If this is changed to something other than 4 seconds the valve may not make the proper adjustments to
the learned position for proper ignition.
Ignition setpoint – defines the learned position 2 identified on the graph. When set to 100% the boiler will try to
ignite with combustion settings the same as position 3. With values less than 100% the boiler will ignite in a lean
condition. With values greater than 100% the boiler will ignite in a rich condition.
Record Ign. Air Level – is an air proving setting at ignition that determines if the boiler has the correct amount
of air flow. If the air flow is low due to blockage or other condition the valve will lockout. When first installing the
boiler and getting the boiler setup the record ign. air level button should be selected, so that the proper air level
can be recorded for the application.
Learned Position 2 – the learned position defines the A/F ratio during ignition. The learned position is defined
by the settings made in the ignition menu and the installation characteristics such as gas supply pressure. The
learned position will adjust automatically within a range from the default position to maintain the proper A/F ratio
at ignition. During this process it is likely that the first few ignitions will be more noticeable than later ignitions. This
is a normal part of the boiler adjusting to the installation.
CAUTION: If the boiler runs through several ignitions with the gas off the Learned position will be adjusted to
richen up the A/F ratio. When the gas is then turned on the ignition might be more noticeable than after the boiler
has gone through several ignitions and the learned position is adjusted correctly.