The Heatmiser DS1 V2 is a 230V mains-powered, surface-mounted electronic dial thermostat designed for conventional, combi-boiler systems & Heat Pump systems. IMI Heatmiser.

Installation & Mounting

⚠️ Safety Warning: Always turn off the mains power to your heating system before removing or wiring the thermostat to prevent electric shock.

1. Separate the unit: Loosen the securing screws on the bottom face of the thermostat to pull the front cover away from the backplate.

2. Mount the backbox: Use the backplate as a template to mark and drill your wall holes, then secure it in place.

3. Wire and reassemble: Complete the wiring connections, snap the front cover back onto the backbox, and tighten the bottom securing screws.

2. Wiring Connections

The DS1 V2 utilizes a volt-free switching output (3A Max). The standard terminal layout is as follows

• L & N: 230V AC Mains Input (Live & Neutral)

• A1 & A2: Volt-free switch contacts (for the boiler/underfloor wiring center).

  • Note for 230V Switched Live systems: If your boiler requires a 230V live signal to turn on (rather than a dry contact), you must add a link wire between L and A1. Terminal A2 then becomes your 230V Switched Live output to the boiler.

• RT+ & RT-: Optional remote air/floor sensor connections (such as a thimble sensor for bathroom control). The thermostat automatically disables its internal sensor when a remote sensor is connected.

3. Setting the Switching Differential (DIP Switches)

The switching differential determines how far the room temperature must drop below your target before the heating kicks back on.

The DS1 V2 has two small DIP switches on the back of the circuit board. You can set them to 1∘C, 2∘C, or 3∘C depending on how frequently you want your boiler to cycle.