Honeywell XE99 SERIES

PRODUCT SPECIFICATION SHEET

The XE99 range of digital thermostats is designed for ON/OFF control of the fan, valves, compressor or auxiliary electric heater in fan-coil and small air-conditioner applications.

Models are available for control of:

• 2-pipe fan-coil units
• 2-pipe fan-coil units with manual heat/cool changeover
• 2-pipe fan-coil units with auxiliary electric heater
• 4-pipe fan-coil units with manual heat/cool changeover
• 4-pipe fan-coil units with sequence (deadband) control
• single stage or 2-stage air-conditioners

Many XE99 models are suitable for multiple applications – they can be configured for each application by changes in the output wiring and the connection of different external links between the wiring terminals.

The fan can also be controlled from the thermostat. In some cases it is wired to run continuously, and can be switched off with the system ON/OFF switch, while with other models there is a choice of running the fan continuously, or cycling it with the thermostat.

Heat/cool changeover operation is also possible. This function can be accomplished either by a manually operated heat/ cool switch on the front of the thermostat or in some versions automatically by the use of a pipe thermostat on the supply water pipe of the fan-coil.

Where a compressor or an auxiliary electric heater is used, this should be normally switched using a relay or contactor, whose operation is controlled by the thermostat.

FEATURES

• Attractive modern styling makes this thermostat ideal for offices or hotels
• Digital display of room ambient temperature, with display of user selected setpoint on demand
• Can be configured to display setpoint temperature only
• Push button adjustment of setpoint
• Switches allow manual control of system operation and fan speed
• Special energy savings mode activated by external input from Energy Management System (EMS) – a window contact or hotel card-key - overrides the temperature setting to installer defined heating and cooling temperatures
• Energy savings input (EMS) can be configured to be normally open circuit or normally closed circuit
• All models have a proportional plus integral (P+I) control algorithm which allows the ON/OFF control to regulate the temperature to within ±0.75°C
• Thermostat mounts directly onto a wall, a standard 65x65mm junction box (hole pitch 60mm) or a US 2x4inch horizontal junction box
• Installer setup mode allowing operating parameters to be changed
• °C or °F display selectable
• Adjustable deadband (some models) for heat & cool sequence control
• Fixed 1°C stage separation (some models) for 2-stage heating or 2-stage cooling operation
• Possibility to configure heating or cooling mode (some models) for energy savings feature
• Adjustable energy savings (setup) cooling setpoint and (setback) heating setpoint
• Adjustable maximum heating and minimum cooling setpoint limits
• Adjustable minimum relay off-times (heating or cooling) for applications requiring compressor short-cycle protection
• EEPROM permanently retains user settings in the event of power loss
• Digital display shows unique icons when cooling or heating relays have operated, or when energy savings mode is active
• Suitable for use with Honeywell valves and actuators: VU448A + VU53/VU54, VC4000 series, V4043/V4044 and thermal actuators M100, Z100, M4450 with associated valves
• Plug-in remote sensor available on some models
• Line voltage (230V~) and low voltage (24V~) models available

SPECIFICATIONS

230 V~ MODELS

* Stage separation = 1°C

24 V~ MODELS

Setpoint range: 10...30°C

Supply voltage : T657xxxxx models 230 V~ (±10%), 50/60 Hz

Supply voltage : T857xxxxx models 24 V~ (+25%,-20%), 50/60 Hz

Thermostat switch: 1 or 2 S.P.D.T. relays (depending on model)

Control : P+I algorithm applied to ON/OFF control gives typical control to ±0.5°C at 22°C at 50% duty cycle. Performance: nominal control to ±0.75°C

Electrical ratings: 4(2) A, at 230 V~ or 24 V~, 12A inrush. Typical loads - fans, zone valves, relays

Operational life: Greater than 100,000 cycles (all loads) for thermostat contacts at 230 V~

Operational life: Greater than 10,000 operations for all manually operated switches

Mounting: Mounts directly onto wall or wall-box - a standard 65x65mm junction box (hole pitch 60mm) or a US 2x4inch horizontal junction box. Mounting screws supplied.

Wiring: 11 screw-in terminals per unit, capable of accepting 2 wires up to 1.5 mm², 2 x 18AWG or 1 x 14AWG

SPECIFICATIONS (CONTINUED)

Energy Savings Input: Voltage-free contact (rating 24Vdc), maximum contact resistance of 1000ohms

Enclosure: Plastic 3-piece housing

Dimensions: 94 x 122 x 37 mm (w x h x d).

Protection class: IP30

Environmental requirements: Operating temperature range 5 to 45°C, Shipping and storage temperature range -20 to 55°C. Humidity range 5 to 95% rh, non-condensing at 26 °C

Remote Sensor: Plug-in connection, with 1.5m cable (where supplied)

Approvals: CE mark, complying with standards EN60730-1 (1995), EN55014-1 (1997), EN55014-2 (1996). Product must be wired as shown for CE compliance.

APPLICATIONS

How to use this Applications Table

1. Use along with Specifications Tables on page 3 to help select the specific XE99 model required.
2. Select the application of interest in the Application column.
3. Then look in the Detailed Applications Capability column to see the many control options and to select the specific application required.
4. When the application has been selected, refer to Wiring Schematic number and any notes in the box immediately to the right.
5. The OS Numbers in the left-most column indicate which model numbers can be chosen. The OS numbers within each box differ only in choice of operating voltage and availability of on-board or remote sensor features.

INSTALLATION

Location

The XE99 Series thermostat is the temperature control element in the fan-coil or air-conditioning system, and must be located about 1.5m above the floor in a position with good air circulation at room temperature. Do not mount it where it could be affected by:

• draughts or dead spots behind doors or in corners
• hot or cold air from ducts
• radiant heat from the sun or appliances
• unheated (uncooled) areas such as an outside wall behind the thermostat
• concealed pipes or chimneys

Mounting the thermostat

Any XE99 Series thermostat can be directly mounted on the wall or horizontally on either a 65x65mm standard junction box or a 2x4inch US junction box (see diagram). Mounting screws are supplied for both alternatives.

IMPORTANT

The installer must be a trained service engineer. Isolate the power supply before beginning installation.

1. Locate the wall-plate in the mounting position, insert the mounting screws through the appropriate holes, and screw into position.
2. Complete the wiring (see later).
3. Attach the thermostat to the wall-plate as follows:
• Locate the 2 side slots on the back of the thermostat
• Align these slots with the 2 side tabs on the wall-plate
• Press down firmly and snap the thermostat into place

Wiring the thermostat

The standard wiring access is via a hole in the centre of the thermostat wall-plate. There is also a single breakout on top of the thermostat for surface wiring from above.

Removing the thermostat

If it becomes necessary to remove the thermostat from the wall-plate:

1. Isolate the power supply before removing the thermostat.
2. Pry the left side of the thermostat away from the wall-plate (see diagram below).
3. Pry the right side of the thermostat away from the wall-plate.
4. Use both hands to pull the thermostat straight away from the wall-plate.
5. NOTE - Improper removal of the thermostat from the wall-plate may damage the device.

DIMENSIONS

94 mm (width) x 122 mm (height) x 37 mm (depth)

OPERATION

Control

Proportional + Integral Control

Like a mechanical thermostat, XE99 has an ON/OFF control output. However, this output is regulated by a proportional + integral algorithm, which enables XE99 to control closer to setpoint than a conventional thermostat and ensures the space temperature is maintained within 0.75°C of the setpoint.

Proportional + integral action eliminates the difference between the temperature setpoint and the effective control point by adjusting the on-time of the output until the control point matches the setpoint. The on-time is based on a fixed cycle rate of 4 cycles/hour for cooling and 8 cycles/hour for heating, and the proportional band is 1.6°C.

Single Stage Control (Cooling or Heating)

In cooling mode the user setpoint will be positioned at the bottom of the Proportional Band, so the setpoint will effectively be the temperature where the cooling switches off.

In heating mode the user setpoint will be positioned at the top of the Proportional Band, and this will be the temperature where the heating switches off.

This also applies to XE99 models with manual heat/cool changeover.

Single Stage Cooling Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. The cooling setpoint is shown as a line, with the proportional band above it. The user setpoint is shown within the proportional band. The text indicates the user setpoint changed from 20.0°C to 21.5°C.

Single Stage Heating Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. The heating setpoint is shown as a line, with the proportional band below it. The user setpoint is shown within the proportional band. The text indicates the user setpoint changed from 23.0°C to 21.5°C.

Single Stage Control – Heat/Cool Changeover

This type of control is only available on T6575B models, where there is a manual Heat/Cool changeover switch. This model can be used for control of 2-pipe fan-coil units (by linking the outputs from both relays) or for 4-pipe fan-coil units.

With cooling selected the user setpoint will be positioned at the bottom of the Proportional Band, so the setpoint will be the temperature where the cooling switches off.

Manual Heat/Cool Changeover Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the operating mode changing from Cooling to Heating. It shows the cooling proportional band, user setpoint, and heating proportional band.

Heating + Cooling Sequence Control with Deadband

This type of control is only available on T6575C models. The required deadband is selected in the Installer Setup Mode. For control purposes the deadband is centered on the user setpoint, so its value then defines the effective heating and cooling setpoints. The cooling switch-off-point will be positioned at the bottom end of the cooling proportional band. Likewise, the heating switch-off point will be positioned at the top end of the heating proportional band. For example, with a deadband of 2°C and a user setpoint of 22°C, the effective heating setpoint will be 21°C and the effective cooling setpoint will be 23°C. Any change to the user setpoint will cause both heating and cooling setpoints to change in parallel, unless they are limited by the minimum cooling setpoint or maximum heating setpoint limits set within the Installer Setup Mode.

Heating + Cooling Sequence Control Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the deadband, cooling proportional band, user setpoint, and heating proportional band. The text indicates the user setpoint changed from 22.0°C to 23.5°C.

Control (continued)

Heat/Cool Changeover + Electric Heat

This type of control is only available on T6575A models. One of the output relays is used to control the valve of a 2-pipe fan-coil unit, and the other relay provides an output for an auxiliary electric heater. The setpoint for the electric heater operation is separated from the normal heat/cool control by an adjustable deadband.

With cooling selected the user setpoint will be positioned at the bottom of the Cooling Proportional Band, at the temperature where the cooling switches off. For the electric heating to switch on, the temperature must decrease until it has passed completely through the deadband.

When heating is selected, the user setpoint remains the same value, but now it is at the top of the heating proportional band. The electric heating setpoint will decrease by 1.6°C so as to maintain the same deadband separation between the bottom of the heating proportional band and the point where the electric heating can come on.

Heat/Cool Changeover + Electric Heat Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the operating mode changing from Cooling to Heating. It shows the cooling proportional band, user setpoint, deadband, heating proportional band, and electric heating proportional band.

2-Stage Control (2-stage cooling or 2-stage heating)

This type of control is only available on T6576 models. There are separate XE99 models dedicated for 2-stage cooling, and others for 2-stage heating (see the Specifications and Applications sections). The stages are separated by a fixed amount, 1°C, so that, once the first stage is 100% ON, the temperature has to change by a further 1°C before the second stage will start to cycle. Examples are shown below.

2-Stage Cooling Control Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates stage 2 cooling proportional band, stage 1 cooling proportional band, user setpoint, and cooling proportional band. It indicates a stage separation of 1°C.

2-Stage Heating Control Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates user setpoint, stage 1 heating proportional band, and stage 2 heating proportional band. It indicates a stage separation of 1°C.

Operating Modes

XE99 has 2 main operating modes, Comfort Mode and Energy Savings Mode, and also has an OFF Mode selected by the on/off switch.

Comfort Mode

This is the normal operating mode where the XE99 controls to the setpoint selected by the user. On initial switch on, or after the On / Off switch has been activated the user setpoint will return to the default value. The control action will be determined by either the default settings or the installer set parameters if the defaults have been altered.

Energy Savings Mode

Energy savings mode is activated by a special Energy Management System (EMS) input from a card-key, occupancy switch or window contact switch. In Energy Savings Mode the XE99 will control to user/installer defined setback setpoints, for increased energy savings. The display will show a $ symbol to indicate when this mode is active.

For example, if the user setpoint is 21°C and the Energy Savings Mode setpoint for cooling (Energy Savings Cooling Setpoint) has been set to 28°C, then XE99 will control to 28°C when it receives the correct input signal. The default Energy Savings Mode setpoints are shown in the table below.

Energy Savings Mode - Setpoints

Activation of Energy Savings Mode

The Energy Savings Input is connected via input terminals 10 and 11 on XE99. It can be configured within the installer setup mode to be activated either by a close circuit or open circuit signal.

By default (Installer Parameter ES=1):

• open circuit = Comfort Mode
• close circuit = Energy Savings Mode

By choice (Installer Parameter ES=0):

• close circuit = Comfort Mode
• open circuit = Energy Savings Mode

The wiring connections are shown below for the EMS input.

Off Mode

If the system switch is set to the Off position, power will be removed from the XE99 electronics and output terminals, and the display will go blank. The thermostat will reboot when power is restored with the On/off switch. Please note - this ON/OFF switch is a functional switch and should not be used as an isolating switch.

Startup

On first powering up, or after the ON/OFF switch has been set to ON, the XE99 undergoes a startup and self-checking sequence. Firstly all the segments on the LCD display are illuminated to check the display. Next a number appears to indicate the software version. The final check is a check of the sensor. The symbol rs will appear to indicate the remote sensor is connected. On completion of the startup sequence, after approximately 2 seconds, XE99 will resume normal control in either Comfort or Economy Mode.

On initial power on, the temperature setpoint defaults are as shown in the following table. The current setpoint is stored in EEPROM, and if the XE99 is switched off, then on again, it will resume control at the last known setpoint.

Power Up Default Setpoints

Fault Detection

The message SF will appear on the display to indicate if a Sensor Fault is detected at power-up, or at any time during the operation of XE99. For remote sensor models, all the sensor connections should be checked and any breaks in the connection should be repaired.

The power must then switched off then on again to reset the fault message, and resume normal control.

Additional Switches

Fan Speed Switch (SP3T line voltage)

Where supplied, the fan switch allows the selection of 3 different settings - low, medium, or high.

System Heat/Cool Switch (SPST low voltage)

Where supplied, this switch signals the microprocessor to operate the relays in either heating or cooling mode. In heating mode the cooling relay is disabled, and in cooling mode the heating relay is disabled.

Fan On/Auto Switch

Where supplied, this switch allows the user to select whether the fan is cycled with temperature, or is operated continuously.

User Interface

Temperature (Comfort) Setpoint

The temperature setpoint can be adjusted between 10°C and 30°C in steps of 0.5°C by using the ▲ and ▼ keys. If °F operation is set within the installer setup mode (see later) the range will be 50°F to 90°F, adjustable in 1°F steps.

Display

The measured room temperature is normally displayed (unless configured otherwise in the installer setup mode) and the first press of the ▲ or ▼ keys will switch to displaying the user setpoint. If no key is pressed for 5 seconds, the display will return to showing the room temperature.

When the cooling relay is closed this will be indicated by a * symbol, whereas closure of the heating relay will be indicated by a symbol.

INSTALLER SETUP MODE

The XE99 Series thermostat allows many of its operating parameters to be adjusted via an Installer Setup Mode. For ease of programming, each operating parameter has a 2 letter identifier code, which is shown on the display during the Installer Setup Mode programming sequence. A brief description of these is shown in the table below. For more details see Pages 9 and 10.

Settable Parameters

Parameter Values

Each parameter has a default value that is used when the XE99 is first powered up. This value can be changed from within the Installer Setup Mode, and once changed it will be stored in EEPROM so it is not lost in the event of power failure.

If the user wishes to restore the parameters to the default values, this can be done by changing the temperature scale ts from °C to °F and back again.

Choice of Parameters

Programming the Parameters

The installer setup mode is accessed by reducing the setpoint to 10°C (50°F), waiting until the room temperature is displayed, and then pressing the ▲ and ▼ keys simultaneously for 3 seconds. If the installer set-up has previously been entered and the Minimum Cooling Setpoint increased above 10°C, the installer set-up mode can be accessed by reducing the setpoint to the new value before pressing the two buttons. If XE99 has been configured to display the setpoint only, then access Installer Setup Mode by reducing the setpoint as before, then waiting for 3 seconds before pressing the ▲ and ▼ keys.

The first parameter identifier will be displayed at this point and the parameter value can be changed by pressing the ▲ key. The first press displays the default value and any subsequent press alters the value. The values will wrap around. To select the parameter value and move to the next parameter the ▼ key is pressed. After the final parameter is selected a further press of the ▼ key exits from programming mode.

The programming mode can be re-entered by pressing the ▲ key.

Programming Example

To enter the installer setup mode:

1. Press ▲ to change the temperature setpoint to 10°C (50°F)
2. Wait until the room temperature is displayed.
3. Press and hold ▲ and ▼ together until ts is displayed.
4. The temperature scale can now be changed, if required, by pressing ▲.
5. Now press ▼ to move to the next parameter.
6. When the parameter code is displayed, press ▲ once to show the factory set value
7. Continue to press ▲ to show all possible values of this parameter in sequence (the values will scroll around).
8. When the desired value is displayed, it is selected by pressing ▼ once. This will also move to the next parameter, whose identifier will now be displayed.
9. Continue to use ▲ to move from one parameter to the next, and ▼ to alter the parameter value.
10. When the last parameter rt has been selected, a final press of ▼ will return the display to the normal operating mode

DETAILED EXPLANATION OF FEATURES

1. Heat or Cool Operating Mode

For single output stage XE99 models (T6570, T8570, T6574, and T8574) it is necessary to configure the thermostat for Cooling or Heating mode, depending on which of these applications is required. This is done from within the Installer Setup Mode, by setting parameter OP. This is necessary for 2 reasons:

1. So that the correct heating symbol (?) or cooling symbol (❄️) is displayed during control operation.
2. So that, when Energy Savings is activated, the thermostat 'knows' whether to control to the Energy Savings Cooling Setpoint or to the Energy Savings Heating Setpoint.

Note the default setting is for Cooling.

2. Energy Savings Cooling Setpoint

This is the minimum Cooling Setpoint which will be used whenever the Energy Savings feature is activated, in order to save energy, for example, when the room is unoccupied. The value can be set in the Installer Setup Mode, from the default value of 25°C up to 30°C in 1°C steps. When activated, this setpoint will not be shown on the display, but Energy Savings Mode will be indicated by a $ symbol. If the user setpoint is made higher than the Energy Savings Cooling Setpoint, then control will be at the user setpoint. See diagrams below that illustrate how Energy Savings operates with Single Stage or Sequence control.

ENERGY SAVINGS - SINGLE STAGE COOLING Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the cooling setpoint, user setpoint, and energy savings activated setpoint. The text indicates Energy Savings Activated to setpoint 25°C.

3. Energy Savings Heating Setpoint

This is the maximum Heating Setpoint which will be used whenever the Energy Savings feature is activated, in order to save energy, for example, when the room is unoccupied. The value can be set in the Installer Setup Mode, from the default value of 18°C down to 10°C in 1°C steps. When activated, this setpoint will not be shown on the display, but Energy Savings Mode will be indicated by a $ symbol. If the user setpoint is made lower than the Energy Savings Heating Setpoint, then control will be at the user setpoint. See diagrams below that illustrate how Energy Savings operates with Single Stage or Sequence control.

ENERGY SAVINGS - SINGLE STAGE HEATING Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the heating setpoint, user setpoint, and energy savings activated setpoint. The text indicates Energy Savings activated to setpoint 18°C.

ENERGY SAVINGS - HEATING + COOLING SEQUENCE CONTROL Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the cooling setpoint, user setpoint, deadband, heating setpoint, and cooling proportional band. The text indicates Energy Savings activated: Cooling setpoint goes to 25°C, Heating setpoint goes to 18°C.

4. Minimum Cooling Off Time

XE99 allows the installer to minimise the cycling of such devices as compressors and fans to prevent increased wear. This short-cycle protection is done by setting a minimum off-time for the control output, either 0, 3, 4, or 5 minutes. This means that when the control relay switches off it will not come on again until the minimum off-time has elapsed. If the setpoint is changed in the meantime, the output will not come on again, but the cooling symbol (*) on the display will flash to indicate minimum cooling off-time is operating. The default is zero minimum off-time.

For heat/cool XE99 models, it is possible to set the minimum cooling off-time and minimum heating off-time separately. For single output stage XE99 models (T6570, T8570, T6574, and T8574) it is possible to set either minimum cooling off-time or minimum heating off-time but not both. In these models, the selection of operating mode determines which minimum off-time can be set.

5. Minimum Heating Off Time

Minimum heating off-time can be set to either 0, 3, 4, or 5 minutes. This means that when the control relay switches off it will not come on again until the minimum off-time has elapsed. If the setpoint is changed in the meantime, the output will not come on again, but the heating symbol (?) on the display will flash to indicate minimum heating off-time is operating. The default is zero minimum off-time.

For heat/cool XE99 models, it is possible to set the minimum cooling off-time and minimum heating off-time separately. For single output stage XE99 models (T6570, T8570, T6574, and T8574) it is possible to set either minimum cooling off-time or minimum heating off-time but not both. In these models, the selection of operating mode determines which minimum off-time can be set.

6. Minimum Cooling Setpoint

To prevent over-cooling and help save energy, XE99 allows the cooling setpoint to be limited so that the user cannot reduce it below a limit value. By default this value is 10°C and can be set anywhere from 10°C to 30°C in 1°C steps from within the Installer Setup Mode. For single stage applications (T6570 and T6574 models) or manual heat/cool changeover (T6575B) it is not possible to reduce the displayed setpoint below the minimum cooling setpoint. For sequence control applications, the user setpoint is in the deadband between cooling and heating setpoints, so it can still be adjusted and shown on the display. However, the cooling setpoint itself will be limited as shown in the diagrams below.

EXPLANATION OF FEATURES (CONTINUED)

MINIMUM COOLING SETPOINT - SINGLE STAGE COOLING Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the cooling setpoint, user setpoint, and minimum cooling setpoint. The text indicates Minimum cooling setpoint = 20°C.

MINIMUM COOLING SETPOINT - HEATING + COOLING SEQUENCE CONTROL Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the cooling setpoint, user setpoint, deadband, and minimum cooling setpoint. The text indicates Minimum cooling setpoint = 20°C.

7. Maximum Heating Setpoint

To prevent over-heating and help save energy, XE99 allows the heating setpoint to be limited so that the user cannot increase it above a limit value. By default this value is 30°C and can be set anywhere from 10°C to 30°C in 1°C steps from within the Installer Setup Mode. For single stage applications (T6570 and T6574 models) or manual heat/cool changeover (T6575B) it is not possible to increase the displayed setpoint above the maximum heating setpoint. For sequence control applications, the user setpoint is in the deadband between cooling and heating setpoints, so it can still be adjusted and shown on the display. However, the heating setpoint itself will be limited as shown in the diagrams below.

MAXIMUM HEATING SETPOINT - SINGLE STAGE HEATING Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the user setpoint and maximum heating setpoint. The text indicates Maximum heating setpoint = 22°C. It also notes that the user setpoint change from 19°C is limited to a maximum of 22°C.

MAXIMUM HEATING SETPOINT - HEATING + COOLING SEQUENCE CONTROL Diagram:

Shows a graph with temperature on the y-axis and time on the x-axis. It illustrates the user setpoint, deadband, and maximum heating setpoint. The text indicates Maximum heating setpoint limited to 22°C.

8. Configuration Of Energy Savings Input

See page 7 for full details.

9. Display of Room Temperature

By default, the display will show measured room temperature as normal, and setpoint temperature by demand, whenever any of the ▲ or ▼ keys is pressed. This feature allows the installer to decide whether to restrict the display to show the temperature setpoint only.

REMOTE SENSOR

The XE99 remote sensor, supplied with some models, is used for sensing the temperature at a distance from the mounting position of the thermostat. A typical application is to sense the return air temperature to the fan-coil unit. The sensor has a special plug for quick connection, and is supplied with 1.5m length of cable.

Connecting the remote sensor

The sensor plug is connected to a pronged socket on the back of the XE99 body. The sensor cable can be run through the wiring access hole on the wall-plate, or alternatively through the break-out on top of the thermostat. If the 1.5m cable supplied is not long enough, it can be extended up to a maximum of 20m, by inserting an additional length of screened cable. For correct operation, the screen wire MUST be connected to the sensor blue wire, as indicated in the diagram. Care must also be taken to ensure good electrical connections are maintained.

WIRING

Diagram 1: T6570A

Shows wiring for a T6570A model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, EMS. Notes indicate connections for Heating, Cooling, and Fan operation.

Diagram 2: T6570B

Shows wiring for a T6570B model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, EMS. Notes indicate connections for Heating, Cooling, and Fan operation, with an optional Fan connection.

Diagram 3: T6574A

Shows wiring for a T6574A model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, EMS. Notes indicate connections for Fan Continuous and Fan Cycled operation.

Diagram 4: T6574A

Shows wiring for a T6574A model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, FAN ON/AUTO, EMS. Notes indicate connections for Heating control and Fan Cycled operation.

Diagram 5: T6574A

Shows wiring for a T6574A model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, EMS. Notes indicate connections for Fan Continuous and Fan Cycled operation.

Diagram 6: T6574B

Shows wiring for a T6574B model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, FAN ON/AUTO, EMS. Notes indicate connections for Heating control and Fan connection.

Diagram 7: T6575A

Shows wiring for a T6575A model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, ELECTRIC HEAT, HEAT/COOL, FAN SPEED, EMS. Notes indicate connections for electric heat relay coil.

Diagram 8: T6575B

Shows wiring for a T6575B model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, HEAT/COOL, FAN SPEED, EMS. Notes indicate connections for 2-pipe fan-coil units and fan continuous operation.

Diagram 9: T6575B

Shows wiring for a T6575B model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, HEAT/COOL, FAN SPEED, EMS. Notes indicate connections for 4-pipe fan-coil units and fan continuous operation.

Diagram 10: T6575C

Shows wiring for a T6575C model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, EMS. Notes indicate that the output from terminal 3 can be used to operate an electric heat contactor or relay.

Diagram 11: T6576A

Shows wiring for a T6576A model. Terminals 1-11 are labeled with functions like ON/OFF, COOL 1, COOL 2, FAN SPEED, EMS. Notes indicate connections for 2-stage cooling.

Diagram 12: T6576A

Shows wiring for a T6576A model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT 1, HEAT 2, FAN SPEED, EMS. Notes indicate connections for 2-stage heating.

Diagram 13: T8574A

Shows wiring for a T8574A model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, EMS. Notes indicate connections for Fan Continuous and Fan Cycled operation.

Diagram 14: T8574A

Shows wiring for a T8574A model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, EMS. Notes indicate connections for Fan Continuous and Fan Cycled operation.

Diagram 15: T8574A

Shows wiring for a T8574A model. Terminals 1-11 are labeled with functions like ON/OFF, AQUASTAT, HEAT, COOL, FAN SPEED, EMS. Notes indicate connections for Fan Continuous and Fan Cycled operation.

Diagram 16: T8574B

Shows wiring for a T8574B model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, FAN ON/AUTO, EMS. Notes indicate connections for Heating control and Fan connection.

Diagram 17: T8575B

Shows wiring for a T8575B model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, HEAT/COOL, FAN SPEED, EMS. Notes indicate connections for 2-pipe fan-coil units and fan continuous operation.

Diagram 18: T8575B

Shows wiring for a T8575B model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, HEAT/COOL, FAN SPEED, EMS. Notes indicate connections for 4-pipe fan-coil units and fan continuous operation.

Diagram 19: T8575C

Shows wiring for a T8575C model. Terminals 1-11 are labeled with functions like ON/OFF, HEAT, COOL, FAN SPEED, EMS. Notes indicate that the output from terminal 3 can be used to operate an electric heat contactor or relay.