Floor Sensor
1. Test the Thermostat Floor Sensor included to make sure it has not been
damaged in handling. Use a digital multimeter set to the 20k
Ω
range. The
resistance varies according to the temperature sensed. These are approximate
values for reference:
Table 1 – Sensor resistances
Temperature
Typical Values
55°F (13°C)
17 k
Ω
65°F (18°C)
13 k
Ω
75°F (24°C)
10 k
Ω
85°F (29°C)
8 k
Ω
2. Pull the floor sensor wire up the wall (or conduit) to the control location.
Consider the following:
• Leave about 6 to 8 inches (15 to 20 cm) of wire for connections later.
• The sensor wire may be cut shorter if desired, but do not cut it shorter until
the sensor is fully installed (see below). Re-strip the sensor wire ends 1/8” to
3/16” (3 mm to 4.5 mm) long. If the ends are stripped longer than this they
may short-circuit resulting in an Err2 code.
• If the sensor wire is not long enough to reach the control location, it may be
extended an additional 15 feet (4.5 m) using minimum 20 AWG 2-conductor
unshielded wire, or an additional 50 feet (15 m) using shielded wire. When
using shielded wire, the “shield” must be connected to the lower sensor
terminal, nearest to Bus A. A junction box may be required by local code for
the connection to this extension wire.
3. After the floor heating system is completely installed according to its
instructions, secure the thick sensor tip to the floor. Consider the following:
• It must be located halfway between heating wires and at least 1 foot into
the heating area.
• Use hot-glue to secure the sensor tip and wire in place.
• Do not cross over a heating wire.
• Avoid placing it in an area where heating wires are spaced further apart than
the rest of the floor, like a large gap between mats or cables.
• Avoid placing it in an area where a heat duct or recessed light will cause
improper measurements.
• Try to avoid locating it where future items such as a clothes hamper or similar
could trap heat and cause improper measurement.
Power Leads from Heating Mat or Cable
Pull the power lead wires from the floor heating system into the control location.
Excess power lead wire may be cut off, but leave about 6 to 8 inches (15 to 20
cm) of wire for connections.
Removing the Thermostat Front Module
1. Remove the Screw Cover at the bottom and loosen the screw.
2. Lift the Front Module away from the Power Module.
Wiring Connections
(see Figure 1 and 2)
Connect the wires as shown in the diagram. Consider the following:
• Gently tug on the wires to make sure they are secure. For added security,
overwrap the Wire Nut connections with electrical tape.
• If the electrical box is metal, a short length of wire must be secured to the
electrical box from the ground connection.
• When connecting the Floor Sensor to the Sensor terminals, it does not matter
which wire goes into which terminal.
• The Bus A and B terminals are used to communicate with a SunStat Relay
II. Please read and follow the instructions provided with the SunStat Relay
II for further details.
Mounting the Thermostat
1. Make sure the power supply to the circuit is turned off at the circuit breaker.
2. Carefully press the wires back into the electrical box.
• DO NOT use the control to push wires in, as this may cause connections to
loosen and possible failure.
3. Use the Mounting Screws provided to secure to the electrical box and tighten
by hand.
• DO NOT over-tighten the screws causing the plastic to distort, as this may
cause improper function of the thermostat.
4. Press the Front Module onto the Power Module. Make sure both tabs at the
top are completely engaged.
• DO NOT install the Front Module with power applied on the Power Module,
as this may cause improper function of the thermostat.
5. Secure the screw at the bottom and replace the Screw Cover.
• DO NOT over-tighten the screw causing it to strip. Turn it until snug.
Figure 1
Figure 2
Power Module
Floor Sensor
Connection
Front
Module
Load 1
Load 2
Cover Screw
Screw
Cover
Line 1
Line 2
