Heatmiser Slimline-RF V3 Wireless Thermostat User Manual

The Heatmiser Slimline-RF V3 is a wireless programmable room thermostat from the Heatmiser Wireless Series. It is designed to send a wireless signal to a compatible Heatmiser receiver to control heating and, in selected configurations, hot water timing.

The official manual covers thermostat installation, battery setup, receiver pairing, comfort levels, hot water switching times, temperature hold, holiday mode, frost mode, factory reset, optional settings, remote air sensor wiring, and Heatmiser support details.

What Is a Programmable Room Thermostat?

A programmable room thermostat combines two functions:

The manual explains that setting the thermostat to a higher temperature does not make the room heat faster. Heating speed depends on the heating system design and size. For better comfort and energy control, users should find the lowest comfortable temperature and let the thermostat follow the programmed schedule.

Key Features

The Heatmiser Slimline-RF V3 includes:

• Wireless thermostat control
• Surface-mounted installation
• Battery-powered operation
• 2 x AAA batteries
• Weekday/weekend, 7-day, and 24-hour programming
• Manual, programmable, and programmable + hot water modes
• Wireless receiver pairing
• UH8-RF and UH8-RF V2 support
• RF-Switch, RF-Switch V2, and RF-Switch 16 Amp support
• Temperature hold
• Holiday mode
• Frost protection
• Hot water override
• Keypad lock
• Battery replacement icon
• Optional remote air probe support
• Factory reset
• Recalibration option
• Failsafe setting

Important Installation Notes

The Slimline-RF V3 is designed to be surface mounted, not flush mounted.

Installation Do’s and Don’ts

The thermostat needs free airflow to sense room temperature correctly. Nearby electric fires, televisions, wall lamps, or table lamps may affect thermostat performance.

Parts and Controls

The Slimline-RF V3 has an LCD screen with six front buttons.

Main Controls

Product Specifications

How to Install the Heatmiser Slimline-RF V3

Installation Steps

1. Separate the front from the back plate
   Insert a small flat-head terminal driver into the slots on the bottom face of the thermostat and carefully separate the front section from the back plate.
2. Mark the fixing points
   Use the back plate as a positioning template and mark two holes on the wall.
3. Drill and insert wall plugs
   Drill the marked positions and insert a wall plug into each hole.
4. Secure the back plate
   Screw the thermostat back plate firmly onto the wall.
5. Clip the front back on
   Attach the thermostat front to the back plate.

Installing the Batteries

The Slimline-RF V3 is supplied with 2 x AAA batteries.

Battery Installation Steps

1. Push and release the battery compartment door on the bottom face of the thermostat.
2. Insert the batteries into the holder.
3. Make sure the polarity is correct using the + / – markings.
4. Push the battery holder back into the thermostat until secure.

The manual clearly states: Do not use rechargeable batteries with this product.

Replacing the Batteries

The thermostat displays a battery icon when the batteries need replacement.

Important note: batteries must be replaced within 1 minute of removal to retain the current clock and comfort level settings.

Receiver Compatibility

The Slimline-RF V3 sends a wireless signal to a receiver to switch heating or hot water.

Supported Receiver Types

For heating only, Feature 10 should be set to Mode 00 or 01. For heating and hot water, Feature 10 should be set to Mode 02. The manual notes that Feature 10 Mode 02 is not suitable for the RF-Switch 16 Amp.

Pairing Menu Explained

The Slimline-RF V3 includes a pairing setup menu.

How to Open the Pairing Menu

1. Turn off the thermostat by holding the Power button for 3 seconds.
2. Hold the H button for 3 seconds until P1 appears.
3. Press the Clock button to move between P1, P2, and P3.

Pairing with UH8-RF V2

Pairing Steps

1. On the UH8-RF V2, press and hold the pairing button on the desired channel until the output LED flashes.
2. On the Slimline-RF V3, turn the thermostat off.
3. Hold H for 3 seconds until P1 appears.
4. Press H once to start the 99-second countdown.
5. The RF icon flashes while the thermostat transmits.
6. If pairing succeeds, the countdown jumps to 00 and the screen goes blank.
7. Press the Power button to turn the thermostat back on.

The manual notes that the Slimline-RF V3 can be paired to multiple channels on the UH8-RF V2.

Pairing with UH8-RF Wiring Centre

The UH8-RF uses rotary switches to set an ID number from 01–99. Each UH8-RF on the system needs a different ID number.

Pairing Steps

1. Note the rotary switch ID number on the UH8-RF.
2. Turn off the Slimline-RF V3.
3. Hold H for 3 seconds until P1 appears.
4. Press the Clock button once to change P1 to P2.
5. Press H to enter P2 settings.
6. Use Up/Down to match the large digits to the UH8-RF rotary switch ID.
7. Press H.
8. Use Up/Down to select the UH8-RF zone number.
9. Press H.
10. Choose zone type:
    • rA = Radiator zone
    • UF = Underfloor heating
11. Press A to save.
12. Press Power to turn the thermostat back on.

Pairing with RF-Switch V2

1. On the RF-Switch V2, press and hold CH1 or CH2 for 5 seconds.
2. The selected channel light flashes.
3. On the Slimline-RF V3, open P1.
4. Press H to start the 99-second countdown.
5. When the RF-Switch V2 detects the signal, the channel light turns off.
6. Press Power to turn the thermostat back on.

Pairing with RF-Switch

1. On the RF-Switch, press and hold CH1 for 5 seconds.
2. The CH1 light flashes.
3. On the Slimline-RF V3, open P1.
4. Press H to start the countdown.
5. The RF icon flashes while transmitting.
6. When pairing succeeds, the CH1 light turns off.

Pairing with RF-Switch 16 Amp

1. On the RF-Switch 16 Amp, press and hold the Pair button for 5 seconds.
2. The Pair light flashes.
3. On the Slimline-RF V3, open P1.
4. Press H to start the 99-second countdown.
5. The RF icon flashes while the thermostat sends the pairing signal.
6. When pairing succeeds, the Pair light turns off.

Important: Feature 10 Mode 02 is not suitable for the RF-Switch 16 Amp unit.

LCD Display Icons

Setting the Clock

1. Turn the thermostat on.
2. Press the Clock key twice.
3. Use Up/Down to set the hours.
4. Press H to confirm.
5. Use Up/Down to set the minutes.
6. Press H to confirm.
7. Use Up/Down to set the day of the week.
8. Press A to confirm and return to the main display.

When configured as programmable with hot water control (Feature 10 = 02), press the Clock key three times to enter the clock setting screen.

Temperature Display

The temperature display uses two values:

Comfort Levels and Programming

The thermostat supports:

Default Comfort Levels

Unused levels should be set to –.–.

How to Program Comfort Levels

1. Press the Clock key once.
2. Use Up/Down to enter the required Wake time.
3. Press H to confirm.
4. Use Up/Down to enter the Wake temperature.
5. Press H to confirm.
6. Repeat for Leave, Return, and Sleep.
7. Set unused periods to –.–.
8. Press A to save.

Setting Hot Water Switching Times

Hot water switching times are only available when the thermostat is configured in programmable with hot water control mode (Feature 10 = 02).

Hot Water Programming Steps

1. Press the Clock key twice.
2. Select the start time for Hot Water Time 1 using Up/Down.
3. Press H to confirm.
4. Select the end time for Hot Water Time 1.
5. Press H to confirm.
6. Repeat for each switching time.
7. Enter –.– for unused periods.

Locking the Thermostat

1. Press and hold A + Down together for 10 seconds.
2. The lock symbol appears on screen.
3. Repeat the same step to unlock.

Temperature Control

1. Press Up or Down.
2. The screen shows SET and the desired temperature.
3. Adjust the set value using Up/Down.
4. Press A to confirm.

This override remains active until the next programmed comfort level.

Temperature Hold

Temperature Hold lets users override the current program for a selected duration.

Set Temperature Hold

1. Press H.
2. Use Up/Down to set the hold time.
3. Press H to confirm.
4. Use Up/Down to set the hold temperature.
5. Press A to confirm.

The display shows Hold For, and the timer counts down before returning to the normal program.

Cancel Temperature Hold

Repeat the same steps and reduce the hold time to 00:00.

Holiday Mode

Holiday mode lowers the set temperature to the frost protection temperature while users are away.

Set Holiday Mode

1. Press H three times until the suitcase icon appears.
2. Use Up/Down to enter the number of holiday days.
3. Press A to confirm.

The holiday period starts at 00:00 the next day. For example, if a 2-day holiday is set on Friday, Saturday is day one, and the thermostat returns to the programmed schedule at 00:00 on Monday.

Hot Water Override

Hot water can be temporarily overridden using the A key.

• If hot water is OFF, pressing A turns it ON.
• If hot water is ON, pressing A turns it OFF.
• Timer ON or Timer OFF flashes when hot water has been overridden.
• The override lasts until the next programmed hot water setting.

Frost Mode

Press the Power button once to enter Frost Mode.

How Frost Mode Works

• The frost icon appears on screen.
• Heating only turns on if room temperature drops below the frost temperature.
• The selectable frost range is 7°C to 17°C.
• If heating activates during frost mode, the flame icon appears.

Set Frost Temperature

1. Press Power once to enter Frost Mode.
2. Use Up/Down to select the frost temperature.
3. Press A to store the setting.

Press Power again to cancel Frost Mode.

Heating On and Off

The flame icon shows heating demand.

• Flame icon visible = heating is ON.
• Flame icon absent = no heating demand, but the thermostat remains active.

To turn the thermostat off completely, press and hold the Power button. The display and heating output turn off completely, provided Frost Protection is disabled.

Factory Reset

1. Press and hold Power to turn the thermostat off.
2. Press and hold Power + Up until the LCD powers up.
3. All icons appear on screen.
4. When the icons disappear, the thermostat has reset.
5. Press Power once to turn the thermostat back on.

Re-Calibrating the Thermostat

1. Press and hold Power to turn the thermostat off.
2. Press and hold Power + Down until the temperature appears.
3. Use Up/Down to set the new calibration temperature.
4. Press A to confirm.
5. Press Power once to turn the thermostat back on.

Optional Settings

Adjusting Optional Settings

1. Press and hold Power to turn the thermostat off.
2. Press and hold the Clock key until the feature screen appears.
3. Use the Clock key to move through features.
4. Use Up/Down to change the setting.
5. Press A to confirm.
6. Press Power once to turn the thermostat back on.

Remote Air Sensor Wiring

The manual includes a remote sensor wiring diagram. To use a remote air probe, connect it to the remote sensor terminals and set Feature 06 to 01.

Troubleshooting Guide

Heatmiser Support

Heatmiser provides technical support, PDFs, FAQs, videos, and specifications through its official channels.Support phone: +44 (0)1254 669090
Website: www.heatmiser.com
Twitter/X: @heatmiseruk
Facebook: facebook.com/thermostats

Official User Manual (PDF)