Boiler room automation Termojet PROFI PLUS (3 circuits + DHW)

Termojet PROFI PLUS is a controller for complex boiler rooms where three independent mixing circuits, a boiler, and solar collectors must be managed simultaneously. The device supports up to two heat sources, OpenTherm 4.0 for boiler communication, and PWM control of the solar collector pump. The 4.3" colour touchscreen displays all system parameters on a single screen.

Technical Specifications

How It Works

The controller simultaneously manages three mixing valves — for example, first-floor underfloor heating, second-floor underfloor heating, and radiators — each with its own heating curve and weekly schedule. The solar pump is connected via the PWM output: the controller smoothly varies the pump speed depending on the temperature difference between the collector and the boiler, increasing the efficiency of the solar system compared to ON/OFF control.

Up to two heat sources (e.g. a gas boiler and solid fuel or a backup boiler) are connected separately; the controller switches between them automatically. The boiler receives its setpoint via OpenTherm 4.0 for precise power modulation. Anti-Legionella disinfection provides scheduled thermal sterilisation of the boiler. Return temperature protection guards the boiler against cold return flow.

Application Scenarios

• Large house, three heating zones. Ground floor, first floor, and basement or garage radiators — each zone has its own schedule and heating curve.
• Solar system + boiler. Solar collectors heat the boiler in summer and reduce gas consumption in the shoulder seasons. The PWM pump selects optimal speeds for maximum heat transfer.
• Two heat sources. Main boiler + backup, or gas + solid fuel — PROFI PLUS controls both and switches automatically.
• Need a fourth circuit? Connect Termojet ONE — it adds another mixing circuit via the RS bus.

Advantages of Termojet PROFI PLUS

• Three independent mixing circuits — flexible zoning of a large house or boiler room with multiple loads.
• Solar collectors with PWM pump control — maximum solar system efficiency without additional regulators.
• OpenTherm 4.0 — two-way digital communication with the boiler, power modulation, and fuel savings.
• Up to two heat sources — flexible bivalent scheme without additional automation.
• 4.3" colour touchscreen — all system parameters on one screen.
• Scalability via ONE and Wi-Fi RS.

Termojet PROFI PLUS and Heat Pump

Three independent zones with weather-compensated control — the optimal configuration for low-temperature systems and air-to-water heat pumps. Low-temperature heating curves allow the heat pump to maintain maximum COP throughout the entire season, while the backup boiler connects automatically only under peak load. Learn more about comprehensive heat pump solutions on the Termojet heat pump website.

Frequently Asked Questions

How many circuits does PROFI PLUS control?
Three mixing circuits plus DHW plus solar collectors. Using the Termojet ONE module, a fourth mixing circuit can be added via the RS bus.

Does PROFI PLUS support solar collectors?
Yes. The controller manages the solar collector pump via a PWM signal, enabling smooth speed regulation and increasing solar system efficiency compared to simple ON/OFF switching. If a two-circuit solution is needed instead of three, consider Termojet LIGHT.