Manual 2100-738C
Page
65 of 73
FIGURE 41
LED Fault Illumination
HP = Green Fault
Illumination
LP = Orange Fault
Illumination
FS (Evap) =
Red Fault
Illumination
CO = Yellow Fault
Illumination
Green Status Light
Troubleshooting Water Modulating
Actuator Diagnostics
The Bard QW*S3D Series is equipped with a water
modulating actuator. The water modulation is achieved
through the operation of a TACO iSeries Smart
Actuator, attached to a TACO 3-way valve.
The iSeries Smart Actuator is a microprocessor-based
valve designed to provide a setpoint (fixed) temperature
to a HVAC system by modulating the position of a
mixing valve. The iSeries Smart Actuator is shown in
Figure 42.
FIGURE 42
iSeries Smart Actuator
Troubleshooting the iSeries Smart Actuator
As in any troubleshooting procedure, it is important
to isolate a problem as much as possible before
proceeding. The error message greatly simplifies
troubleshooting of the iSeries-S. When the control
flashes an error message, identify the fault by observing
the LED status light code and follow standard testing
procedures to confirm the problem. The LED status
code and error can be diagnosed by following the light
sequences in the multi-status LED table (Table 14).
If a wiring fault is suspected, return to the wiring
diagram located on the unit door and carefully inspect
all external wiring and wiring connections.
Testing the Sensors
A good quality test meter capable of measuring up to
5,000 kΩ (1 kΩ= 1000 Ω) is required to measure
the sensor resistance. In addition to this, the actual
temperature must be measured with a good quality
digital thermometer.
First measure the temperature using the thermometer
and then measure the resistance of the sensor at the
iSeries Smart Actuator. The wires from the sensor
must not be connected to the iSeries Smart Actuator
while this test is performed. The wiring terminals are
easily removed by pulling them from the iSeries Smart
MIS-4135
SENSOR
BOILER
SUPPLY
C
COMMON
24 VAC
OUTDOOR
POWER INPUT
R
= RED
SENSOR
ERROR
STATUS LIGHT
POWER = GREEN
MIS-4135
TABLE 14
Multi-Status LED
LED
LED Status
ISeries Smart Actuator Status
Green
Solid
Power On
Flash
Reduced Output
(System Protection Activated)
Red
Flash, Pause,
Flash, Pause,
Flash, ...
System Supply Sensor Fault
The iSeries-S operates at a
fixed output