How to Replace a Myson Room Thermostat
Upgrading a tired old dial thermostat to a modern programmable or smart control is one of the easiest heating improvements — and it can noticeably cut your bills. Here's what's involved.
Before you start — safety first
Mains heating controls carry a risk of electric shock. Always isolate the power to the heating system at the fused spur or consumer unit before removing any thermostat. If you are not confident working with mains wiring, use a qualified electrician or heating engineer.
Step 1 — Note the existing wiring
Remove the cover of your old thermostat and take a clear photo of the wiring before disconnecting anything. Note which wires go to which terminals (typically labelled with numbers such as 1, 2, 3 or L, N, and a switched live).
Step 2 — Remove the old stat
With the power off, disconnect the wires and unscrew the backplate from the wall. Check the new thermostat's backplate lines up, or use the new fixings supplied.
Step 3 — Fit and wire the new thermostat
Wire the new thermostat to match your notes and the manufacturer's diagram. For wireless (RF) models, you'll wire the receiver near the boiler and simply mount the battery-powered thermostat where you want it — no new cabling required.
Step 4 — Power up and pair
Restore power, set the time and temperature, and (for RF models) pair the thermostat with its receiver following the instructions. OpenTherm-compatible controls can modulate the boiler for extra efficiency.
Choosing a replacement
Decide between a simple dial stat, a programmable thermostat, or a smart wireless control. If running a new cable is difficult, a wireless (RF) thermostat is usually the easiest upgrade.
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