Form #: SIDOM.4 Page | 16 Revised: 03/19
For RA Cooling or DA Heating (See Table 2 on pg. 12): Adjust HI STAT ∆P to the desired
minimum airflow by turning knob CLOCKWISE with 20 psig (or a pressure greater than the
reset stop point) at port “T”. The HI STAT ∆P must be set last. The HI STAT ∆P setting will
be affected by the LO STAT ∆P setting.
NOTE:
If the LO STAT ΔP Limit must be set at “0” (zero minimum), do not turn the LO STAT
ΔP knob completely clockwise. The knob will adjust one and one-half turns after a zero
minimum is reached. Turning the LO STAT ΔP knob completely clockwise will result in
a negative reset condition. This means that when the controller begins to reset at the
reset start point, it must first overcome the negative adjustment and will not begin to
reset from “0” until a higher thermostat reset pressure is reached. This negative reset
will also reduce the effective range of the controller by reducing the low end reset,
narrowing the reset span. If a zero minimum is required, adjust the LO STAT ΔP knob
until the controller just starts to open the damper, then back-off one-quarter turn and
verify zero airflow. (This is typically 2-1/2 knob rotations counter clockwise from the fully
clockwise position.)
After the “LO STAT ∆P” and “HI STAT ∆P” initial adjustments are made, cycle the
thermostat pressure a few times to settle the internal reset mechanisms and verify
settings. Fine-tune the settings if necessary. The thermostat pressure may be left at a
high pressure and the “G” port cap may be removed and replaced to cycle the reset
mechanism.
RESET START Setting is factory set at 8.0 psig. This is the lowest thermostat pressure that the LO
STAT ∆P airflow will begin to reset towards the HI STAT ∆P airflow. To change the RESET START
setting; regulate thermostat pressure to the “T” port to the desired reset start point pressure, adjust
RESET START adjustment until pressure at the “G” port is slightly higher than 0 psig, i.e., 0.1 psig.
NOTE:
For Dual Duct Units the reset start must be adjusted to 3.0 psig. ON THE HEATING
SIDE ONLY
The “G” port taps into the controller’s internal reset chamber, which always starts at 0
psig. The RESET START adjustment is a positive bias adjustment that sets the desired
thermostat start point to the controller’s internal reset start point of 0 psig.
RESET SPAN Setting is factory set at 5.0 psig. This is the required change in thermostat pressure
that the controller will reset between the LO STAT ∆P setting and the HI STAT ∆P setting. To change
the RESET SPAN setting; adjust RESET SPAN adjustment until pressure at the “G” port equals the
desired reset span pressure. (Do Not Adjust)
NOTE:
The “G” port taps into the controller’s internal reset chamber, which will always be
at a pressure between 0 psig and the RESET SPAN pressure.
To Next Page
Loading...
