ET-81 PROGRAMMABLE TIMERSTAT INSTRUCTIONS

Introduction

The ET-81 is a smart Timerstat designed to control your electric underfloor heating system, helping to minimise energy use.

Technical Specification

Supply voltage: 85-265V 50/60Hz

Maximum switching current: 15A/3.3KW

Standby power: < 1W

Ingress Protection: IP21

Display Symbols

The thermostat display features several indicators:

Clock: Displays the current time.
Period: Indicates the current heating period (e.g., Wake, Leave, Return, Sleep).
Temperature: Shows the current measured temperature.
Return: Displays the target temperature for the current period.
Confirm: Button used to confirm settings.
Power: Button used to turn the device on or off.
Day: Shows the current day of the week.
ON/OFF: Indicates the heating status (On or Off).
Up: Button to increase values or navigate upwards.
Down: Button to decrease values or navigate downwards.

The main screen typically shows the current time (e.g., 11:29), day (THU.), floor temperature (21.5°C), and heating status (ON).

Functions and User Operation

On/Off

Press the [Power Button] to turn the timerstat on or off.

Temporarily Override Temperature

In 'on' mode, press the [Up Arrow] or [Down Arrow] to change the current period's temperature setting. Press the [Confirm Button] to confirm the new setting and return to the normal screen.

Note: When frost protection mode is active, the timerstat will maintain the frost protection temperature even when in 'off' mode. The timerstat will revert to the normal programmed settings at the start of the next scheduled time period.

Set the Time

In 'on' mode, press the [Confirm Button] and the time will be displayed. Press the [Confirm Button] again to enter day set mode.

Use the [Up Arrow] or [Down Arrow] to set the day. Press the [Confirm Button] to confirm and enter hour set mode.

Use the [Up Arrow] or [Down Arrow] to set the hour. Press the [Confirm Button] to confirm and enter minute set mode.

Use the [Up Arrow] or [Down Arrow] to set the minute. Press the [Confirm Button] to confirm, then press the [Confirm Button] again to revert to the normal screen.

Key-lock

Setting the key-lock can prevent children and others from accidentally changing timerstat parameters.

In 'on' mode, press and hold the [Confirm Button] for 3 seconds to lock the timerstat. Press and hold the [Confirm Button] again for 3 seconds to cancel the key-lock.

Holiday Mode

In holiday mode, the ET-81 will maintain the frost protection temperature until the holiday period ends.

In 'on' mode, press the [Confirm Button] to enter setting. Press the [Up Arrow] or [Down Arrow] to select 'Holiday'. Press the [Confirm Button] to enter holiday days set mode. Press the [Up Arrow] or [Down Arrow] to set the number of holiday days.

Press the [Confirm Button] to confirm and return to the normal screen.

Note: In holiday mode, 'HOLIDAY LEFT' days remaining will show on the display. Double press the [Confirm Button] to cancel holiday mode.

Hold Mode

The ET-81 will maintain a set 'hold temperature' until hold mode is switched off.

In 'on' mode, press the [Confirm Button] to enter setting. Press the [Up Arrow] or [Down Arrow] to select 'Hold'. Press the [Confirm Button] to enter hold mode. Press the [Up Arrow] or [Down Arrow] to set hold to ON.

Press the [Confirm Button] to enter the hold temperature setting. Press the [Up Arrow] or [Down Arrow] to set the desired hold temperature. Press the [Confirm Button] to confirm and return to the normal screen.

Note: Whilst in hold mode, 'HOLD' will be displayed. Double press the [Confirm Button] to cancel hold mode.

Timer Setting

Each day of the week has 4 time periods. You should assign a temperature to each period. Set the temperature above room ambient temperature for heating to activate until the desired temperature is reached, or set a lower temperature to prevent heating during that period.

In 'on' mode, press the [Confirm Button] to enter setting. Press the [Up Arrow] or [Down Arrow] to select 'Edit'.

Note: Weekdays (Mon-Fri) are set as a group, while Saturday and Sunday are set individually.

Press the [Confirm Button] to enter period selection. Press the [Up Arrow] or [Down Arrow] to select the period to be set (e.g., Wake, Leave, Return, Sleep).

Press the [Confirm Button] to enter start time set. Press the [Up Arrow] or [Down Arrow] to select the start time hour. Press the [Confirm Button] to enter minute set. Press the [Up Arrow] or [Down Arrow] to select the start time minute.

Press the [Confirm Button] to enter temperature set. Press the [Up Arrow] or [Down Arrow] to select the temperature.

Press the [Confirm Button] to enter day selection. Press the [Up Arrow] or [Down Arrow] to select the day to be set.

Press the [Confirm Button] to confirm the current period's settings, which also takes you back to period selection. Repeat the previous steps for Leave, Return, and Sleep periods.

When all four time periods have been set for a day, press the [Confirm Button] to move to the next day selection. Repeat previous steps for Saturday and Sunday.

Press the [Confirm Button] twice to return to the normal screen, or allow the timer to time out. Your settings will be saved.

Default Period Settings for Time and Temperature

Day	Wake	Leave	Return	Sleep
Mon - Fri	07:00, 22°C	08:30, 19°C	17:00, 22°C	22:00, 19°C
Sat / Sun	08:00, 22°C	08:30, 22°C	17:00, 22°C	22:00, 19°C

Note: Do not attempt to remove time periods, as this may damage the timerstat.

Troubleshooting - Fault Codes

E1: Built-in sensor short-circuit or disconnected.
E2: Floor sensor damaged/disconnected/clamped on to insulation or incorrect floor sensor installed.

Dimensions

The physical dimensions of the ET-81 timerstat are approximately 87mm in height, 60mm in width, and 51mm in depth. Other minor dimensions are also indicated in the diagram.

Note: The floor sensor resistance should be in the range of 10K Ohms. Please check this during installation.

Advanced Settings

These settings are typically configured by the installer.

In 'on' mode, press the [Confirm Button] to enter setting mode. Press the [Up Arrow] or [Down Arrow] to select 'Setup'. Press the [Confirm Button] to enter advanced settings.

Each parameter can be accessed by pressing the [Confirm Button] and then adjusting the values using the [Up Arrow] or [Down Arrow].

No	Name	Default	Ranges
1	Temp calibration - Floor sensor - Room sensor	0°C 0°C	-5°C to +5°C -5°C to +5°C
2	Frost protection Frost protection temperature	OFF 5°C	OFF/ON -5°C to +15°C
3	Sensor selection	Floor Sensor	Room air sensor/Floor sensor/Both sensors
4	Floor temperature limit	30°C	20°C to 50°C
5	Temperature unit	°C	°C/°F
6	Output delay	0S	0S/30S/60S/90S
7	Temperature tolerance	1°C	0.5°C/1°C/2°C/3°C
8	Brightness	80%	0% - 100%
9	Energy use power rating	0W	0W - 3500W
10	Schedule	5+1+1	7/5+1+1
11	Adaptive Function	OFF	OFF/ON
12	Factory Reset	Back	Yes/Back

Press the [Confirm Button] twice to return to the normal screen or allow the timer to time out. Any settings changed will be saved.

Wiring Instructions

The timerstat should be connected to the power supply (220V-250V, 50/60Hz) at terminals N1, N, L, and L1. The Floor Sensor connects to the SENSOR terminals. The unit supports a maximum load of 16A and has IP21 CE certification.

Notes On Advanced Settings

1. Temp calibration: Calibrate the temperature detected by the room sensor or floor sensor.
2. Anti-frozen function: This option helps prevent your room from freezing in very cold weather.
3. Sensor select: Choose between Room sensor, Floor sensor, or Both sensors (Room sensor with floor temperature limit).
4. Floor temp limit: Always use the floor sensor for underfloor heating applications.
5. Temp unit: Select between Celsius (°C) and Fahrenheit (°F).
6. Output delay: This option helps avoid inadvertent operation of the heating system.
7. Temp tolerance: The default value is 1°C. The thermostat starts heating when the actual temperature is 1°C lower than the set temperature and stops heating when it is 1°C higher than the set temperature.
8. Brightness: Adjust the brightness of the display.
9. Energy use: N/A.
10. Schedule: Select a weekly schedule to edit. Two options are available: '7' (each day from Mon to Sun can be set individually) and '5+1+1' (Mon-Fri share the same settings, Sat and Sun can be set individually).
11. Adaptive function: After several days of installation and use, this function ensures the required temperature is reached before the next scheduled event begins. It is recommended to switch this on only when a regular heating pattern has been established.
12. Reset: Selecting 'Yes' restores all parameters to their default values.

Installation Instructions

This Timerstat should only be wired by a 'Part P' qualified Electrician, adhering to IEE regulations. The power supply must be connected via an RCD protected circuit and a correctly fused switched spur isolator. Failure to follow these provisions will void the guarantee.

Before connecting, test the resistance of the heating cable(s) against the values specified in the relevant installation manual to ensure the cable is not damaged. Also, test between live/earth and neutral/earth for a zero reading. Verify the floor probe resistance is within the 10K Ohms range.

The ET-81 timerstat should be mounted using an 86x86x35mm deep wall box.

To install, loosen the silver fixing screw on the bottom of the timerstat and separate the front from the back section.

Wire the back section of the timerstat as per the diagram. A maximum of two heating cables can connect directly to the wire connectors. For more than two cables, use a junction box with a single correctly sized wire connecting to the timerstat.

Connect the main's earth and the heating cable earth behind the timerstat using a block connector. Ensure the floor probe is connected (it is not polarised); otherwise, the timerstat will not function correctly.

Reassemble the front to the back section, ensuring the pins are correctly located in the socket on the back. Tighten the silver screw to secure the unit.

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