Electronic Thermostat STELPRO ST402PFF 4000 W | Montreal, Laval, Longueuil, South Shore and North Shore

A fan heater isn't controlled the same way as a baseboard heater. Its fan blows warm air into the room and heats it quickly, which makes it the go-to choice for entrances, vestibules, bathrooms, basements and some commercial spaces. But to work properly, it needs a thermostat designed for this type of unit. The Stelpro ST402PFF is a programmable electronic thermostat rated at 4000 W and made specifically for fan heaters. It pairs a programmable schedule with Boost mode for a quick temperature rise and Lobby mode. At AirGreen, we install it when a space heated by a fan unit needs its heat on a schedule.

Scheduling made for fan heaters

The ST402PFF lets you program 4 periods on weekdays and 2 periods on weekends. In an entrance or vestibule, the schedule can call for a warmer temperature when people come and go, and a lower setpoint the rest of the time. In a finished basement used mostly in the evening, the temperature can stay low during the day and come back up before evening. According to Stelpro, programming can deliver up to 20% in energy savings.

3-wire connection and Boost mode

Unlike baseboard thermostats, the ST402PFF uses a 3-wire connection. That connection unlocks Boost mode, which gives you a quick rise in temperature. It's especially handy in a room that has to warm up fast, like a bathroom before a shower or an entrance after the door has been opened again and again. Before recommending this model, our technicians check that the right conductors are there.

Lobby mode

The ST402PFF also offers Lobby mode, designed for entrance halls and spaces people pass through. In an apartment building, a store or an office, these spaces have their own heating needs, and this mode lets you set the thermostat up for that kind of use.

Capacity and accuracy

The thermostat runs on 120, 208 or 240 V, with a range of 150 to 2000 W at 120 V, 260 to 3475 W at 208 V and 300 to 4000 W at 240 V. Thermistor sensing holds the temperature within ±0.5 °C (1 °F), over a setpoint range of 5 to 30 °C (41 to 86 °F). The digital display can be set to °C or °F.

Protection and installation

If the power goes out, your schedule is kept for 2 hours. The S3 mounting plate is included and makes for a solid installation. The thermostat is certified to CSA C828-19 and comes in a white moulded plastic housing.

Where to install it

The ST402PFF suits entrances and vestibules in houses and buildings, bathrooms with a wall-mounted fan heater, finished basements, workshops and small shops. In each of these spaces, a set schedule paired with a fan unit gives you quick comfort when the space is in use and lower energy use the rest of the time. With a capacity of 4000 W at 240 V, it can run fairly powerful units, suited to larger spaces or spaces more exposed to the cold.

Part of Stelpro's FF series

Stelpro's FF series groups together its thermostats for fan units. The ST402PFF is the programmable 4000 W version. The ST252NPFF (2500 W) and ST402NPFF (4000 W) are non-programmable and rely on a manual ECO mode, while keeping Boost mode and Lobby mode. If your space is used on a regular schedule, the ST402PFF makes the most sense; for irregular use, a non-programmable model may be enough. For baseboard heaters or convectors without a fan, go with the ST402P or the ST302P instead.

Technical specifications

• Type: programmable line-voltage electronic thermostat for fan heaters
• Systems: electric fan heaters (3-wire)
• Voltage: 120/208/240 V
• Load range: 150 to 2000 W at 120 V; 260 to 3475 W at 208 V; 300 to 4000 W at 240 V (max. 4000 W at 240 V)
• Programming: 4 periods on weekdays, 2 on weekends
• Protection: settings kept during a power outage (2 hours)
• Wiring: 3-wire, with Boost mode (fast temperature rise)
• Other features: Lobby mode
• Accuracy: ±0.5 °C (1 °F), thermistor sensing
• Setpoint: 5 to 30 °C (41 to 86 °F)
• Display: digital, °C or °F (your choice)
• Mounting: S3 plate included
• Savings: up to 20%, according to Stelpro
• Certification: CSA C828-19
• Colour: white, moulded plastic

Professional installation and use

Our qualified technicians start by identifying the fan heater, its wattage and the wiring available at the thermostat box. A 3-wire connection is a must if you want Boost mode. We shut off the circuit at the panel, confirm there's no voltage, mount the S3 plate and wire the thermostat. Once the power is back on, we check that the heating and the fan work properly, then set up a schedule with you that matches how the room is used.

Energy-saving tips

A fan heater warms the air quickly, so there's no need to schedule the warm-up far in advance. In a small room, a short head start is usually enough. Save Boost mode for the times when speed really matters, and let the schedule do the rest. In an entrance, a moderate setpoint beats a high one, since warm air escapes every time the door opens.

Maintenance

A fan heater's fan pulls in dust. Clean the grille at the start of every heating season to keep the airflow up and avoid smells at start-up. The thermostat only needs an occasional dusting.

Why AirGreen

A family-owned HVAC company with an RBQ licence, more than 15 years of experience and a showroom in Boucherville, AirGreen installs and upgrades residential and commercial heating systems. To buy the Stelpro ST402PFF thermostat and have it professionally installed, get in touch with us. We serve Montreal, Laval, Longueuil, the North Shore and the South Shore.

Stelpro documents

Stelpro spec sheet (PDF) · Stelpro user guide (PDF)