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To wire the SPT sensor to the controller:
1. Partially cut , then bend and pull off the outer jacket of
the Rnet cable(s), being careful not to nick the inner
insulation.
2. Strip about
1
/
4
in. of the inner insulation from each wire.
See Fig. 26.
3. Wire each terminal on the sensor to the same terminal on
the controller. See Fig. 15-24. Table 8 shows the recom-
mended Rnet wiring scheme.
Table 8 — Rnet Wiring
NOTE: The wire should be connected to the terminal shown.
Wiring a Supply Air Temperature (SAT) Sensor — The
SAT sensor is required for reheat applications.
If the cable used to wire the SAT sensor to the controller
will be less than 100 ft, an unshielded 22 AWG (American
Wire Gage) cable should be used. If the cable will be greater
than 100 ft, a shield 22 AWG cable should be used. The cable
should have a maximum length of 500 ft.
To wire the SAT sensor to the controller:
1. Wire the sensor to the controller. See Fig. 15-24.
2. Verify that the Enable SAT jumper is on.
3. Verify that the Enable SAT and Remote jumper is in the
left position.
Wiring an Indoor Air Quality (IAQ) Sensor
— An IAQ
sensor monitors CO
2
levels. The WSHP Open controller uses
this information to adjust the outside-air dampers to provide
proper ventilation. An IAQ sensor can be wall-mounted or
mounted in a return air duct. (Duct installation requires an aspi-
rator box assembly.)
The sensor has a range of 0 to 2000 ppm and a linear 4 to
20 mA output. This is converted to 1 to 5 vdc by a 250-ohm,
1
/
4
watt, 2% tolerance resistor connected across the zone con-
troller’s IAQ input terminals.
NOTE: Do not use a relative humidity sensor and CO
2
sensor
on the same zone controller if both sensors are powered off the
board. If sensors are externally powered, both sensors may be
used on the same zone controller.
If the cable used to wire the IAQ sensor to the controller
will be less than 100 ft, an unshielded 22 AWG (American
Wire Gage) cable should be used. If the cable will be greater
than 100 ft, a shield 22 AWG cable should be used. The cable
should have a maximum length of 500 ft.
To wire the IAQ sensor to the controller:
1. Wire the sensor to the controller. See Fig. 15-24.
2. Install a field-supplied 250-ohm,
1
/
4
watt, 2% tolerance
resistor across the controller’s RH/IAQ and Gnd
terminals.
3. Verify the the RH/IAQ jumper is set to 0 to 5 vdc.
Wiring a Relative Humidity (RH) Sensor
— The RH sensor
is used for zone humidity control (dehumidification) if the
WSHP unit has a dehumidification device. If not, the sensor
only monitors humidity.
NOTE: Do not use a relative humidity sensor and CO
2
sensor
on the same zone controller if both sensors are powered off the
board. If sensors are externally powered, both sensors may be
used on the same zone controller.
If the cable used to wire the RH sensor to the controller will
be less than 100 ft, an unshielded 22 AWG (American Wire
Gage) cable should be used. If the cable will be greater than
100 ft, a shield 22 AWG cable should be used. The cable
should have a maximum length of 500 ft.
To wire the RH sensor to the controller:
1. Strip the outer jacket from the cable for at least 4 inches.
2. Strip
1
/
4
in. of insulation from each wire.
3. Wire the sensor to the controller.
Step 9 — Wire Field Controls
THERMOSTAT CONNECTIONS — The thermostat
should be wired directly to the ECM control board. See
Fig. 27.
WATER FREEZE PROTECTION — The Aquazone™ con-
trol allows the field selection of source fluid freeze protection
points through jumpers. The factory setting of jumper JW3
(FP1) is set for water at 30 F. In earth loop applications, jumper
JW3 should be clipped to change the setting to 10 F when
using antifreeze in colder earth loop applications. See Fig. 28.
NOTE: The extended range option should be selected
with water temperatures below 60 F to prevent internal
condensation.
AIR COIL FREEZE PROTECTION — The air coil freeze
protection jumper JW2 (FP2) is factory set for 30 F and should
not need adjusting.
ACCESSORY CONNECTIONS — Terminal A on the control
is provided to control accessory devices such as water valves,
electronic air cleaners, humidifiers, etc. This signal operates
with the compressor terminal. See Fig. 29. Refer to the specific
unit wiring schematic for details.
NOTE: The A terminal should only be used with 24-volt
signals — not line voltage signals.
WATER SOLENOID VALVES — An external solenoid
valve(s) should be used on ground water installations to shut
off flow to the unit when the compressor is not operating. A
slow closing valve may be required to help reduce water
hammer. Figure 29 shows typical wiring for a 24-vac external
solenoid valve. Figures 30 and 31 illustrate typical slow closing
water control valve wiring for Taco 500 Series and Taco ESP
Series valves. Slow closing valves take approximately 60 sec.
to open (very little water will flow before 45 sec.). Once fully
open, an end switch allows the compressor to be energized (on-
ly on valves with end switches). Only relay or triac based elec-
tronic thermostats should be used with slow closing valves.
When wired as shown, the slow closing valve will operate
properly with the following notations:
1. The valve will remain open during a unit lockout.
2. The valve will draw approximately 25 to 35 VA through
the “Y” signal of the thermostat.
WIRE TERMINAL
Red +12-v
Black .Rnet
White Rnet+
Green Gnd
Fig. 26 — Rnet Cable Wire
OUTER JACKET
INNER INSULATION
.25 IN.
a50-8443
–
IMPORTANT: Connecting a water solenoid valve can
overheat the anticipators of electromechanical thermo-
stats. Only use relay based electronic thermostats.