* To remove a connector from the control module, pry with a screwdriver.
Heat pump
HVAC
Installation Guide
Non-programmable H/C Controller
1. Introduction
1.1
The TH146-N-U electronic controller can be used with any of the following heating/cooling systems:
The following devices can be connected to the controller:
air recirculation fan
humidifier
dehumidifier or air exchanger
dual-register meter (dual energy)
remote control device (for the unoccupied mode)
1.2
• CT280-3H3C control module
• TH146 console with two wall anchors and mounting screws
• AC144-03 outdoor temperature sensor (3 m or 10 ft) with mount-
Configure the control module according to your type of heating/cooling system using DIP switches on the back of the module.
Install the control module near the heating/cooling system, away
from any heat source.
2.2
Control Module (CT280-3H3C)
User Console (TH146)
1.3
• RC845 relay (see section 2.4)
• AC146-410 plenum temperature sensor (see section 2.8)
• CT241 telephone controller (see section 2.10)
TH146-N-U 1/12
Accessories
Install the console in a central location. Avoid locations with air
drafts (e.g., top of staircase or air outlet) or stagnant air (behind a
door). Do not install the console on a wall hiding air ducts nor
expose it to direct sunlight.
NOTE: If this controller replaces an old thermostat, any two of the
wires that were connected to the thermostat can be used to connect
the user console to the control module. The maximum wiring length
is 30 m (100 ft).
Choose a location about 1.5 m (5 ft) above the floor on an
inside wall.
Loosen the captive screw under the console.
Detach the console from its base by pulling the bottom section.
Secure the base using the wall anchors and screws.
Connect the console to controller terminals TH and TH (no
polarity).
Install the sensor on the side of the plenum and
position it such that its aperture faces the air flow.
Connect the sensor to controller terminals PS
and CS (no polarity). For more information, refer
to the instructions provided with the sensor.
NOTE: The maximum wiring length is 30 m (100
ft).
2.3
The terminals used to connect the heating/cooling system depend
on the type of system. See the appropriate wiring table on page 4.
2.4
If you have an add-on installation, you might need an RC845 relay
to connect the furnace (auxiliary heat) and its fan to the controller.
Install the relay near the control module and connect the wires as
follows:
•relay terminals W, G and C to controller terminals W1, G and C.
•relay terminals T and T to the appropriate furnace terminals: T
NOTE: Refer to the relay’s installation instructions for more details.
If you have a 3H1C or 4H2C heat pump, a second RC845 relay
might be required to connect the second auxiliary heat.
2.5
Connect the humidifier in series with the power supply between
controller terminals H and H (dry contact).
2.6
Connect the dehumidifier or air exchanger in series with the power
supply between controller terminals D and D (dry contact).
2.7
The outdoor sensor is required for the following:
When installing the sensor, observe the following guidelines:
Install the sensor using its mounting clip and connect it to controller
terminals OS and CS (no polarity).
NOTE: The maximum wiring length is 30 m (100 ft).
Heating/Cooling System
RC845 Relay
and T (oil); TH and TH (gas); R and W (electric).
Humidifier
Dehumidifier / Air Exchanger
Outdoor Sensor (AC144-03)
• outdoor temperature display
• balance points (heat pumps only, see section 4.2)
• defrost point (heat pumps only, see section 4.3)
• automatic humidity control (see section 5.5)
• Avoid locations where the sensor can be covered with snow
or exposed to direct sunlight.
• Avoid air outlets and concealed chimneys or stove pipes.
2.9
NOTE: The dual-energy input can be used only with a heat pump
equipped with auxiliary heat.
The dual-energy input can be connected to the dual-register meter
equipped with a normally open (NO) dry contact. Connect the controller terminals DE and CC to the meter terminals (yellow and red
wires).
The contact closes when the outdoor temperature drops below the
temperature setting on the meter. When the contact is closed, the
heat pump is disabled and only the auxiliary heat can be used.
2.10
To use the unoccupied mode, the controller requires a remote control device such as Aube’s CT241 telephone controller equipped
with a normally open (NO) dry contact placed between terminals UN
and CC of the controller. The unoccupied mode is activated when
the contact closes. (See section 5.6.)
Dual-energy Input
Unoccupied Mode Input
3. Configuration
3.1
To access the configuration switches, loosen the captive screw
under the console and separate the console from its base by pulling
it from the bottom part.
3.1.1 Backlight (SW1-1)
BL ON: The screen is always backlit.
AUTO: The screen is backlit only when a button is pressed. The
backlight remains on for 12 seconds.
3.1.2Access Mode (SW1-2)
INST: Installer mode. Gives access to all configuration parameters.
USER: User mode. Gives access to configuration parameter 17
(humidity setpoint or humidity offset) only.
3.1.3 Keypad Lock (SW1-3)
I: The keypad is locked. Settings cannot be changed.
O: The keypad is unlocked.
Configuration Switches
NOTE: In installer mode, the short-cycle protection is disabled
and the interstage delay is reduced to 1 minute.
2.8
Plenum Sensor (AC146-410)
3.2
Software Configuration
Place the console in Installer mode (INST) using the SW1-2 switch
The plenum sensor is required for the following:
• low temperature limit inside the plenum (HVAC only)
• high temperature limit inside the plenum (HVAC only)
• fan limit if gas heating is used (HVAC only)
• high pressure protection during defrost cycle (This protection
is generally needed for add-on installations only. It is not
needed if the heat pump is not connected to the controller
terminal WW.)
TH146-N-U 2/12
on the back of the console.
Press the Mode button for 3 seconds to access the configuration
menu (see page 8). The first menu item (parameter) is displayed.
To view another menu item, briefly press the Mode button.
To modify a parameter, press either button.
To exit the configuration menu, press .
Return the console to User mode (USER).
4. Principles of Operation
the controller is configured for a new installation, the heat pump
and the auxiliary heat can operate simultaneously.
4.1
With automatic heating/cooling mode changeover, there’s no need
to adjust the controller at every change of season or weather condition. The controller switches automatically between heating mode
and cooling mode to maintain the desired temperature. The mode
changeover is triggered as follows:
•The controller switches to cooling mode when the indoor tem-
•The controller switches to heating mode when the indoor tem-
4.2
Balance points are used to disable the heat pump or the auxiliary
heating when the outdoor temperature is below or above a set temperature.
•When the outdoor temperature is below the balance point low
•When the outdoor temperature is above the balance point high
NOTE: Balance Points cannot be used if the AC144-03 outdoor
temperature sensor is not connected to the controller.
Automatic Heating/Cooling Changeover
perature is higher than the setpoint by more than 1.5°C (2.5°F)
for 15 minutes.
perature is lower than the setpoint by more than 1.5°C (2.5°F)
for 15 minutes.
Balance Points (heat pumps only)
(bP L), the heat pump is disabled and only auxiliary heating can
be used (see page 8, item 2).
(bP H), the auxiliary heat is disabled and only the heat pump
can be used (see page 8, item 3).
4.5
Interstage Delay is the time allocated for the temperature to return
to an acceptable value when it deviates too far from the setpoint. If
this time has elapsed, the next heating or cooling stage is activated.
The heating or cooling stage will be deactivated when the temperature returns to an acceptable value. The Interstage Delay is fixed at
4 minutes if the controller is configured for an HVAC system and is
user-adjustable if it is configured for a heat pump (see page 8,
item 6).
4.6
Low Temperature Limit (LLMT) and High Temperature Limit (HLMT)
are used to keep the plenum from becoming too cold or too hot.
During cooling, if the plenum temperature is lower than LLMT, a
cooling stage is deactivated starting with the one that was last activated. If, after a while, the temperature is still too low, another cooling stage is deactivated and so on. Likewise, during heating, if the
plenum temperature is higher than HLMT, a heating stage is deactivated starting with the one that was last activated. If, after a while,
the temperature is still too high, another heating stage is deactivated and so on. (see page 8, items 7 and 8.)
WARNING: LLMT and HLMT can be used in parallel with an
UL353-approved device but they do not replace such device.
NOTE: LLMT and HLMT cannot be used if the plenum temperature
sensor is not connected to the controller.
4.7
Interstage Delay
Low and High Temperature Limits
Smart Fan
4.3
The auxiliary heat is activated during defrost except under the following conditions:
•When the outdoor temperature is above the defrost point (see
•When the plenum temperature is above 40°C (104°F) for
NOTE: The auxiliary heat’s short-cycle protection is disabled during
defrost.
4.4
The controller can be configured for either of the following types of
heat pump installations (see page 8, item 5).
•Add-on Installation: This type of installation is performed
•New Installation: In this type of installation, as there is not
Heating During Defrost (heat pumps only)
page 8, item 4). NOTE: This condition will not apply if the
AC144-03 outdoor sensor is not connected to the controller.
add-on installations only. The auxiliary heat is re-activated
when the plenum temperature drops below 32°C (90°F).
NOTE: This condition will not apply if the AC146-410 plenum
sensor is not connected to the controller.
Types of Heat Pump Installations
when adding a heat pump to an existing furnace. When the
heat pump is installed, the furnace becomes the auxiliary heat
source. In this type of installation, the indoor coils are usually
installed downstream of the auxiliary heat source. When the
controller is configured for an add-on installation, the heat
pump is disabled during auxiliary heating to prevent overpressure.
already a furnace, the auxiliary heat source is installed at the
same time as the heat pump. In this type of installation, the
indoor coils are located upstream of the auxiliary heat. When
TH146-N-U 3/12
When Smart Fan is enabled (see page 8, item 12), the fan operates
as follows:
•During the unoccupied mode (i.e., when you are away from
home), the fan operates only when heating or cooling is activated.
•The fan operates continuously the rest of the time.
NOTE: For Smart Fan to work, set the fan to On (see section 5.2).
4.8
If a humidifier and a dehumidifier are both connected to the controller, the controller will automatically switch between the two devices
to maintain the desired humidity level. The changeover occurs when
the humidity deviates from the setpoint by more than 3% for 30 minutes.