The modulating valve actuator has settings for min fire. The min fire rate needs to be set to put a minimum amount of air and fuel to make the burner burn at min fire. We define min fire as a 75 degree temperature gain over ambient inlet (the air temp in the laundry or outside, not the inlet temp after the flame)
You can see the damper position on the bottom of the damper shaft. The cut in the shaft indicates the damper position.
Here are a few pictures of the modulating valve that help you know what to adjust.
1. The spindle needs to be adjusted properly so that when the damper is closed the spindle knows that the valve is closed.
2. The min fire is adjusted by programming a drycode at min plus 1 air for 20 minutes. The 20 minutes should give you time to make adjustments at the valve.
3. Set the switch on the modulator at min fire. (See the picture for the switch positions). This switch setting overrides any signal we give it from our controller and the modulator goes to the min fire position.
We set the 3rd red adjustment band from the bottom at about 30 as a start point for the min fire position.
For reference, the lowest band is set for 90. The second ring from the bottom is set at "0".
Monitor the OUTLET temp and see if you gain 75 degrees over ambient air temp. If too high, lower the min fire red band, if too low, raise it.
3. The spindle can be disconnected from the drive motor so you can make adjustments. The small black button uncouples the spindle and then you can spin the spindle free of the valve moving. The spindle must be set to zero when the valve is closed.
5. The indicator on the top of the spindle is movable. So, when the stem if shut, set the indicator to 0.
