From standalone thermostats to a connected system in one day: configuration A0

There is a type of system you find everywhere, from early-2000s houses to small offices: underfloor heating, a wired thermostat in each room, each thermostat connected to its zone’s actuator. It works, but every room acts on its own. The boiler does not know how many zones are calling, the flow temperature never changes, and nothing is recorded.

To upgrade standalone thermostats to a connected system you do not need to change the thermostats. Brick’s configuration A0 starts from them: it leaves them where they are and adds a controller that coordinates everything else. In this article we follow the working day, hour by hour.

The starting point

A typical A0 system looks like this:

• an underfloor circuit with up to 4 zones, each with its own wired thermostat;
• actuators on the manifold, driven directly by the thermostats;
• a boiler or heat pump, with its own thermostat or a demand contact;
• often a mixing valve with a fixed-point or thermostatic controller;
• a cylinder for domestic hot water.

Every part works. What is missing is coordination: weather compensation on the flow, heat demand based on the zones, hot water priority, data.

What A0 does

With A0 the thermostats stay in the rooms and keep doing their job: saying whether the room needs heat. But instead of driving the actuator directly, their contact goes to the controller. From there, Brick decides.

• It opens the actuator of the calling zone, as before.
• It runs the underfloor pump only if at least one zone is calling.
• It controls the flow temperature with the mixing valve, following a heating curve instead of a fixed value.
• It sends the heat demand to the heat source when needed, and handles domestic hot water priority.
• It logs everything: zone calls, temperatures, running hours.

For the people who live there almost nothing changes: the thermostats are the same. What changes is how the plant room works, and from that day on the data is visible.

The materials

Before starting, have everything on site:

• the panel with Brick, protection devices, power supplies and terminals, built in the workshop to the A0 wiring diagram;
• a strap-on flow sensor and an outdoor sensor;
• an actuator for the mixing valve, if the existing one cannot be controlled;
• sensor cable and control cable;
• the diagram of the existing system, even hand-drawn, with the zones numbered.

Building the panel in the workshop is the choice that makes the job fit into a day. On site you mount and connect; you don’t wire from scratch.

The day, hour by hour

8 am, site check. Compare the diagram with the real system: which loops serve which zone, where the thermostat cables arrive, how the boiler is connected. Photograph everything before touching anything, including the existing wiring inside the boiler’s terminal box.

9 am, the panel. Mount the panel in the plant room, bring in a protected supply, connect the pump, mixing valve and heat demand. Fit the flow sensor, in good contact with the pipe and insulated, and the outdoor sensor, on the north wall.

12 noon, the manifold. Disconnect the actuators from the thermostats and bring them back to the panel. The thermostat cables go to Brick’s inputs. This is when the heating is off, usually for a couple of hours.

2 pm, set-up. Brick with the A0 configuration already has the logic in place: assign inputs and outputs to the zones, set the starting heating curve, the flow limits and hot water priority.

4 pm, testing. One zone at a time: force a call from the thermostat and check that the right actuator opens, the pump starts, the valve moves and the demand reaches the heat source. Then test the hot water.

5 pm, handover. Show the client what has changed: for them, almost nothing, the thermostats are the same. Hand over the updated diagram, the app credentials and the sign-off record.

What can go wrong

On a day like this, delays almost always come from the same places.

• Mislabelled zones. The living room thermostat actually drives the kitchen loop. You find out during testing, unless you checked in the morning.
• Thermostats switching 230 V to the actuators. Some thermostats switch mains voltage directly. Their contact has to reach Brick through a suitable input, not be connected as it is: the A0 diagram shows how.
• A boiler without a demand contact. Some boilers only have an input for their own programmer, or a proprietary bus. Check the manual beforehand.
• A seized mixing valve. A valve that has not moved for years may not move now. Test it during the site check.

After handover

The real tuning starts afterwards. In the first two weeks, look at the charts: does the flow follow the curve? Do the zones reach temperature? Is the boiler starting too often? Adjust the curve as explained in the article on weather compensation, one step at a time.

And after a few months, if the client wants, the next step is simple: replace the wired thermostats with wireless sensors and move to control from the app, as in the B configurations. The controller and panel stay the same. It is the same path described in the article on going from one to eight zones, done in two stages.

How to explain it to the client

The simplest way to put it to the client: the thermostats stay the same, but from today something listens to all of them together. The standalone layout, with each thermostat working on its own, becomes a connected system, with links to Brick coordinating zones, flow temperature and heat source. It is the quickest way to show what really changes, and what stays as it is.

A0 and A1

A0 covers up to 4 zones. For larger systems, up to 8 zones, there is A1, with the same logic. Either way, anyone who already knows underfloor heating control will find a familiar layout: the only change is who coordinates the zones.