RTH2520
69-1867EF—04 03-11 2/8
2.3.1 2-wire Heating
2.3.2 2-wire Cooling
2.3.3 3-wire Heating
2.3.4 3-wire Cooling
2.3.5 4-wire Heating and Cooling
2.3.6 5-wire Heating and Cooling
Note
: Remove the red jumper wire between terminals Rc and Rh.
2.4 Setting JP2 Jumper
The jumper specifies how the fan will operate
when it is placed in automatic mode (see sec-
tion 3.2).
2.5 Installing the Batteries
Gently pull out the battery cover.
Install the batteries as shown. Observe the polarity.
Reinstall the battery cover. You will hear a clicking sound.
After the batteries are installed, the thermostat performs a
sequence of tests for approximately 5 seconds.
Afterwards, the screen displays the actual
temperature. It is normal that the displayed
temperature be higher than the ambient
temperature if you are holding the thermo-
stat. Once installed on the wall, the thermostat will display the ambi-
ent temperature. By default, the setpoint is 70°F (21°C).
The time and day settings flash to indicate that they must be set
(see section 5.1).
2.6 Completing the Installation
Once the baseplate and the batteries are installed, mount the
thermostat on the baseplate.
Secure the thermostat using the locking screw and install the
faceplate.
Apply power back to the system.
3.1 System Operating Mode
Use this selector switch to place the system in Heat-
ing mode (HEAT) or Cooling mode (COOL), or to set
both modes to Off.
Note
: When you place the thermostat in Cooling mode, you might
need to wait up to five minutes before cooling can start. This is a
safety feature for the compressor. will flash on the screen during
the delay.
Heat relay
Jumper
Cool relay
Jumper
Fan relay
Heat relay
Jumper
Cool relay
Fan relay
Jumper
Heat relay
Cool relay
Fan relay
Jumper
Fan relay
Cool relay
Heat relay
HG
Leave the jumper in this position if you
have a gas or oil heating system.
HE
Move the jumper to this position if you
have an electric heating system.
3. Basic Functions
JP2 jumper
