Do I need an electrician to fit a Heatmiser NeoStat?

A like-for-like thermostat swap on an existing wired circuit is generally a homeowner task. You need an electrician if the existing wiring is unusual, if you are adding a new circuit, or if you want to install the neoHub and integrate with a smart system involving new wiring.

What is the difference between a NeoStat and a NeoStat-E?

The standard NeoStat controls a wet central heating system (gas or oil boiler). The NeoStat-E is designed for electric underfloor heating: it has a floor sensor input and controls the heating mat or cable directly rather than a boiler relay.

Can a NeoStat work without the neoHub?

Yes. The NeoStat operates fully as a standalone programmable thermostat. The neoHub is only needed if you want remote control via the Heatmiser app or integration with home automation systems.

How to Install a Heatmiser NeoStat Thermostat (UK)

Helpful video reference. The Heatmiser NeoStat installation video from the official Heatmiser channel walks through the back plate fitting and terminal connections for the NeoStat. Worth watching before you start, particularly the section on the two-wire and three-wire wiring options.

Before you start. The thermostat wiring in most UK homes is low-voltage signal wiring, but it is connected to a mains-fed programmer or boiler which runs at 230 V. Isolate at the programmer's fused spur, or at the boiler's spur switch, before touching any terminals. Confirm dead with a voltage tester. If your thermostat wiring uses mains voltage rather than a volt-free relay circuit, you will see live conductors at the stat - these must be isolated at the consumer unit before you proceed.

1. Switch off the heating supply

Find the fused connection unit (FCU) or spur switch that supplies your programmer or boiler controls. Switch it off - this de-energises the thermostat wiring. If you cannot find a local spur, switch off the relevant circuit at the consumer unit and lock it off or remove the fuse.

Test at the existing thermostat terminals with a voltage tester before removing any screws. No reading? Good. A reading means the circuit is still live - go back and find the right isolation point.

2. Photograph and label the existing wiring

Unscrew the old thermostat from its back plate and ease it away from the wall. Before disconnecting anything, take a clear photo of every terminal from directly in front and from a slight angle. Most UK room thermostats use two or three conductors:

Two-wire circuit: the thermostat simply makes and breaks the circuit. One wire goes to COM, the other to NO.
Three-wire circuit: separate live, neutral and switched live (or a call wire). You may also have an earth.

If there are more wires than you expected, or if any of them look mains-weight (2.5 mm brown and blue twin-and-earth), stop and check what you have before going further.

3. Remove the old back plate

With the wires disconnected and labelled, unscrew the old back plate. If the cables come out of the wall loosely, tape them temporarily to the wall surface so they cannot disappear back through the plaster before you are ready.

4. Fit the NeoStat back plate

Hold the new back plate against the wall and use a spirit level to get it square. Mark the two fixing hole positions in pencil. Drill at 5 mm and plug the holes. Feed the cables through the central cutout and screw the back plate down firmly - it needs to sit flush because the thermostat clips onto it and any tilt will show.

5. Connect the wiring

Open the NeoStat box and read the wiring diagram inside the lid - Heatmiser prints a clear diagram for both the two-wire and three-wire scenarios. The terminal labels to know:

Two-wire heating circuit: connect one wire to COM and the other to NO. The NeoStat closes this circuit when it calls for heat.
Three-wire circuit with mains supply: connect brown (live) to L, blue (neutral) to N, and the switched live or call wire to COM. The NO terminal then feeds the boiler enable input.
Earth: if an earth conductor is present, connect it to the earth terminal on the back plate.

Tighten each terminal screw firmly. Pull gently on each wire after tightening - it should not move.

6. Clip the NeoStat onto its back plate

Align the NeoStat with the back plate, press it squarely onto the fixing clips and it will snap into position. Restore the boiler supply. The NeoStat display should light up within a few seconds.

7. Set the time, date and heating schedule

The first thing the NeoStat prompts you to do is set the current time and day. Work through the on-screen menu. Once the clock is right, go into the schedule menu and set your preferred on and off times for each day of the week. The NeoStat supports up to six time periods per day.

8. Test the system

Set the target temperature a few degrees above the current room temperature. After a moment you should hear the boiler fire. Let the room come up to temperature and confirm the NeoStat drops the boiler call off when it reaches the set point. If the boiler does not fire, recheck your terminal connections against the wiring diagram.

Stop and call an electrician if: you find the stat wiring is connected directly to a mains live at 230 V (not a low-voltage relay circuit), if there are more conductors than the diagrams in the NeoStat box show, if the boiler does not fire after correct wiring, or if you see any scorching or heat damage around the old back plate.

When to call us

A straightforward like-for-like stat swap is well within what most homeowners can manage. It becomes a job for an electrician when the existing wiring is unusual, when you want to add the neoHub and run new data cabling, or when the heating system itself stops responding correctly after the swap.

Need a Heatmiser NeoStat fitted in Sandwich?

Richard can fit thermostats, programmers and full heating controls at a fair local rate.

Contact Richard

How to install a Heatmiser NeoStat thermostat