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Page 45
Explanation of Thermostat Dip Switches
Dip switches are located on the back of the thermostat
This dip switch configures the thermostat to control a
conventional gas/electric system or a heat pump. If
your system is anything other than a heat pump,
leave this switch set for GAS/EL.*
When the GAS/EL or HP dip switch is configured for HP,
this dip switch (O or B) must be set to control the
appropriate reversing valve. If O is chosen, the W1/O/B
terminal will energize in cooling. If B is chosen, the
W1/O/B terminal will energize in heating.
*When GAS/EL or HP is set for GAS/EL:
This switch (GAS or ELEC) controls how the thermostat
will control the Fan (G) terminal in heating mode. When
GAS is chosen, the thermostat will not energize the
Fan (G) terminal in heating. When ELEC is chosen
the thermostat will energize the fan in heating.
*For some commercial heat pumps, this switch may need to
be set for GAS/EL. Consult the commercial heat pump
literature.
*When GAS/EL or HP is set for HP:
This switch (GAS or ELEC) defines the Aux Heat type.
When GAS is chosen, the auxiliary heat will not be
allowed to run during heat pump operation. When
using a Dual Fuel system, set this switch for GAS.
When ELEC is chosen, up to two stages of auxiliary
strip heat will be allowed to run.
Installation Instructions
GAS/EL
1
2
3
ON
HP
O
GAS
B
ELEC
1
2
3
ON
1
2
3
ON
GAS/EL
HP
HP
GAS/EL
OR
1
2
3
ON
1
2
3
ON
O
B
O
B
OR
GAS
ELEC
GAS
ELEC
OR
1
2
3
ON
1
2
3
ON
OUT+
OUT
C
R
G
Y1
Y2
W1-O-B
W2
W3
GAS/EL
1
2
3
ON
HP
O
GAS
B
ELEC
Summary of Contents for TSTATG4271GT
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