AERCO SWDW68 U-Tube Double-Wall Heaters w/ECS - Manual (Page 29)

AC-105 INSTRUCTIONS - ECS & CXT-E
Rev B Mar 2013 4-1
CHAPTER 4 ADJUSTMENT
4.1 INTRODUCTION
This chapter explains the procedures you use to adjust the CXT-E Control Valve (“Valve”), Electronic
CXT-E Actuator (“Actuator”) and Electronic Control System (ECS). The ECS is factory adjusted to the
setpoint temperature specified on the sales order, and the Actuator is factory adjusted (auto-stroked) to
ensure that it correctly operates the Valve from the fully-open to the fully-closed positions.
To the extent necessary, perform all the procedures listed in 4.2 and 4.3 before placing the system into
operation and after replacing the Valve or any ECS components.
CAUTION
BE SURE that all steam shutoff valves are fully closed before performing any of the following
adjustment procedures.
4.2 ADJUSTING THE ELECTRONIC CXT-E ACTUATOR
The Actuator is self-calibrating for all size Valves. The Actuator is powered by 24 VDC and controlled by a
linear 4-to-20 mA control signal, as follows:
• A 4 mA control signal input operates the Valve to the fully-closed position (Valve shaft down)
• A 20 mA signal strokes the Valve to the fully-open position (Valve shaft up).
When properly connected to the ECS, applying power to the Control Box applies +24 VDC power to the
Actuator. The power switch is located on the right side of the Control Box, as illustrated in
Figure 4-2.
TEMP CONTROLLER
HOLD
RUN AUTO
MAN
2408
PT.NO.
OVER TEMP SWITCH
PANEL
DOOR
OVER-TEMP
SWITCH
TEMPERATURE
CONTROLLER
POWER
SWITCH
[
SEE
FIGURE 4-3
Figure 4-1. Control Box – Front View
IMPORTANT
Perform this adjustment after three months of use and annually thereafter. Also, this adjustment is
mandatory each time the Actuator is replaced or when mechanical adjustments are made to the
Valve or its linkage.