Daikin Rebel Applied DPSA - Maxitrol EXA Star Controller; Primary Manifold Pressure Adjustment; Modulating Valve Setting Adjustment


www.DaikinApplied.com 155 IM 1287-6 • REBEL APPLIED ROOFTOP
Maxitrol EXA Star Controller
NOTICE
These instructions are intended for the adjustment and troubleshooting of
the Maxitrol EXA (E40H and E50H) modulating gas valves used with the
Beckett VB1285 modulating control. Always set manifold pressures to the
value on the appliance’s rating plate.
WARNING
All adjustments should be made by a qualied service agency in
accordance with the manufacturer’s instructions and all applicable codes
and requirements of the authority having jurisdiction. If the information in
these instructions is not followed exactly, a re, explosion or production of
carbon monoxide may result causing property damage, personal injury, or
loss of life. The qualied service agency performing this work assumes the
responsibility for the proper adjustment of the appliance.
WARNING
Adjusting the Modulating valve beyond its physical limits may result in
permanent damage to the valve and production of Carbon Monoxide during
modulation. Serious injury and death can result if not adjusted correctly.
Pre-Adjustment Verication
Prior to adjusting gas pressure, ensure the following items are
checked and veried:
1. Check VB1285 ignition control for any error codes.
a. If error codes are present, unit performance may
be a󰀨ected. Clear error codes from the control by
powerering o󰀨 for 10 seconds.
2. Verify inlet pressure to the safety valve is within the
correct range per the appliance rating plate and adjust if
necessary.
3. Verify gas pressure at the outlet of the safety valve is
between:
— 4.5 and 5.0” W.C. if NG
— 11.0 11.5” W.C. if LP
— If gas pressure is outside of the designated ranges,
correct and check manifold pressure.
— Refer to Figure 207 on page 153 for location.
4. Remove modulating valve cover and verify that the
modulating valve is wired correctly according to the
following wire colors and description:
— 24VAC (+) (Blue)
— 24VAC (-) (Yellow)
— 10VDC (+) (Red)
— 10VDC (-) (White)
— Ensure purple com wire is connected correctly, as
shown in Figure 61 on page 56
— Correct any wiring that is incorrect per the wiring
diagram.
5. Verify that dip switches on the modulating valve are set
correctly.
— Switch 1 (OFF)
— Switch 2 (ON)
— Switch 3 (OFF)
Primary Manifold Pressure Adjustment
1. Using the MicroTech unit controller’s “Manual Control”
menu, set the heating output to 100%.
NOTE: Ensure all required dampers are opened and
adequate airow is provided across the heating
section in manual control prior to sending heat
demand to the heating section.
2. If modulating manifold pressure is between 3.0 and 3.5”
W.C., adjust by increasing safety valve pressure.
a. Remove the brass regulator screw on the safety
valve.
b. Increase safety valve pressure by turning the
plastic screw clockwise until the desired manifold
pressure is achieved.
c. Replace the brass screw cover.
Modulating Valve Setting Adjustment
WARNING
Adjusting the modulating valve beyond its physical limits may result in
permanent damage to the valve and production of carbon monoxide (CO)
during modulation. Serious injury and death can result if not adjusted
correctly.
Use calibration procedure dened in “Maxitrol EXA Star Valve Over-Traveled
State Calibration” on page 82 if modulating valve is believed to be in a
mechanically over-traveled state.
If safety valve outlet pressure is between 4.5 and 5.0” W.C.
and modulating manifold pressure is below 3.0” W.C. (refer
to Figure 207 on page 153 for location). Modulating valve
settings may need to be adjusted. Perform the following
procedure to adjust the modulating valve:
1. Remove the blue cover on the modulating valve.
2. For high input adjustment, press and hold button #1 until
the red LED light comes on. Refer to Figure 213 on page
156.
3. Once the red light is on, toggle between buttons #1 and
#2 to adjust the manifold pressure.
— Button #1 increases gas ow
— Button #2 decreases gas ow
— Each press of a button will move the set point of the
valve up or down by one step. It is best to adjust with
discrete clicks of the button so as not to drive the
valve beyond its physical limits.
4. Press and hold both buttons simultaneously to set valve.
Red light will turn o󰀨.
5. For low input adjustment, use the MicroTech unit
controller’s “Manual Control” menu to set the heating
output to 25% or when the MicroTech unit controller
outputs 2 VDC from the analog output.
6. Press and hold button #2 until the red LED starts
ashing. Refer to Figure 213 on page 156.