Floor Heating Expansion Unit STELPRO CONCERTO EXPANSION STF362XU | Montreal, Laval, Longueuil, South Shore and North Shore

A large basement, an open kitchen or a generous main bathroom can call for more heating cable than one thermostat can power. The usual fix is to install several thermostats, each with its own zone and setting. That makes daily use more complicated and clutters the wall. The Stelpro CONCERTO EXPANSION STF362XU expansion unit solves it another way: it adds electrical capacity to a CONCERTO thermostat, which stays the only control point for the whole floor.

More heated floor, still one thermostat

What it actually does

The STF362XU is not a thermostat. It has no set point of its own and no settings screen. It works as a slave unit that follows the commands of the CONCERTO thermostat it is connected to. Each unit handles up to 15 A, which is 1800 W at 120 V, 3120 W at 208 V or 3600 W at 240 V. When the total load of an electric floor heating system goes over the 15 A of a single thermostat, you add as many units as needed to split up the cable or mat sections.

Compatibility

The expansion unit works with every thermostat in the CONCERTO line: STF362WF (Wi-Fi), STF362PTS (touchscreen), STF362P (programmable) and STF362NP (manual). So the main thermostat you choose decides which features you get across the whole floor: programming, remote control, energy use log or manual adjustment. The expansion unit simply powers the extra sections in step with it.

Daisy-chain wiring

The units connect in a daisy chain, with a maximum of 80 ft (25 m) between two units. That leaves room to place each unit near the floor section it powers, for example in the next room or in a utility wall, while the main thermostat stays wherever is most convenient for you.

Safety

Each unit has its own built-in Class A GFCI with a test light, plus a terminal block and a double-pole (DPST) switch that cuts both poles. Every floor section gets the same protection as the one wired directly to the thermostat. That is essential in damp rooms.

Technical specifications

• Function: expansion unit for electric floor heating, adds capacity to a CONCERTO thermostat
• Capacity: up to 15 A per unit; maximum 1800 W at 120 V, 3120 W at 208 V, 3600 W at 240 V
• Power supply: line voltage 120/208/240 V
• Daisy-chain connection, maximum 80 ft (25 m) between units
• Built-in Class A GFCI with test light
• Terminal block and double-pole (DPST) switch that cuts both poles
• Compatible with CONCERTO thermostats STF362WF, STF362PTS, STF362P and STF362NP
• White moulded plastic housing

Designing and installing a large heated floor

Planning

It all starts with working out the floor's total load, section by section. Our technicians add up the wattage of the cables or mats, check the home's voltage and figure out how many units are needed. They plan where each unit goes and how the daisy chain runs, staying within the maximum distance between units. This step avoids bad surprises when the power is turned on.

Installation

Each floor section is measured before it is wired, then connected to its unit. The main CONCERTO thermostat goes in the most useful spot, usually near the entrance to the room. We then test each GFCI separately and check that every section heats properly when the thermostat calls for heat.

The right main thermostat

Since the expansion unit repeats the thermostat's commands, the thermostat you pick matters. For a large area heated at set times, a programmable model like the STF362P or the STF362PTS limits energy use automatically. For a room you want to control remotely, the STF362WF is the best fit. We talk it over with you before settling on the setup.

Maintenance

Test the GFCI on each unit every month, not just the one on the thermostat. Keep the units accessible and clear. If one section of the floor stays cold while the rest heats up, get in touch with us. It is often a tripped GFCI or a connection that needs checking.

AirGreen, for your electric heating

AirGreen Inc. is a family-owned HVAC company established in Montreal for more than 15 years. We hold an RBQ licence and have a showroom in Boucherville. We design complete installations, from the thermostat to the expansion units, and tie them into your home's overall comfort, whether you heat with electric baseboard heaters or wall-mounted heat pumps.

To buy the Stelpro CONCERTO EXPANSION STF362XU expansion unit and have it professionally installed with your CONCERTO thermostat, contact AirGreen. We serve Montreal, Laval, Longueuil, the North Shore and the South Shore.

Stelpro documents

Stelpro spec sheet (PDF)