Installations
Control water-based underfloor heating at the manifold – one DIN-rail relay for several zones.
Updated: October 2026
The loops terminate at a manifold, and each is opened and closed by a thermal actuator. Count the actuators, not the rooms: a manifold with six loops needs six switched outputs.
DIN rail. Three potential-free contacts for 24 V actuators, or a manifold with its own supply.
DIN rail. Four 230 V channels with power metering per zone, and a display that shows the channel names.
Both mount on DIN rail, so they sit in the cabinet beside the manifold.
Water-based systems are slow, so room temperature is the control variable. Use a wireless Shelly BLU H&T Display ZB in each room: battery-powered, with temperature and humidity on its own display.
Battery-powered room sensor with display.
The same sensor in black.
Mount it at 1.5 m, away from radiators, direct sun and external walls. The sensor reaches the app through a Shelly with Bluetooth gateway switched on – the Pro 3 or Pro 4PM works if the room is within range of the cabinet.
Connect each actuator to its own relay output, and bring the circulation pump under the same controller so it only runs when at least one loop is open.
Torque every terminal to the value printed on the device before re-energising.
Before you name anything, write down which relay and output feeds which loop and room. The names in the next step come straight from this sheet, and the next electrician – or you, in three years – can find every output without opening the cabinet.
Download the template and fill it in on screen or on paper:
Sensors: assign each sensor to its room in the app and give it a plain name, e.g. “Temperature sensor Guest bathroom”.
Relay channels: name each Pro 4PM channel from the documentation, using the pattern Function R(relay), O(output) - Room:
Heating R1, O1 - Guest bathroomR is the relay’s number in the cabinet, O is the output on that relay. Anyone reading the app can find the physical output without the paper.
Then go to Device → Settings → Device settings → Device name, switch on Sync device name and press Save. The channel names now show on the Pro 4PM’s display, one per channel. The sync only runs from the app to the device, so rename channels in the app, not on the relay.
Prefer a thermostat on the wall? See Wall Display as thermostat.
SW as a manual override, or leave it set to maximum. Do not put both in series and expect predictable behaviour.