Circulator pump Termojet AUTO energy-saving APE 25/40/130 mm

Termojet AUTO APE 25/40/130 mm circulating pump — a compact energy-saving pump with an ECM motor (electronically commutated permanent-magnet motor) and wet rotor for heating systems and underfloor heating with low hydraulic resistance. Installation length 130 mm, threaded connection 1″ internal thread (union nut), power consumption 5–25 W, maximum head 4 m, flow rate up to 2,5 m³/h. The pump automatically adapts its speed to the current system load.

Technical Specifications

AUTO Operating Modes

Constant differential pressure (Δp-c). The pump maintains a set pressure difference between supply and return regardless of how many thermostatic valves are open. Δp-c mode is the standard for radiator heating with thermostatic heads on each unit.

Proportional differential pressure (Δp-v). The differential pressure decreases proportionally to the reduction in flow rate. When some underfloor heating circuits close, the pump independently reduces pressure and speed — less noise, less consumption. Δp-v mode is recommended for underfloor heating systems and combined schemes.

Applications

• Underfloor heating systems with low hydraulic circuit resistance — 4 m head covers the vast majority of small and medium floor circuits.
• Pump group NG-46 (130 mm) — installation length 130 mm is the standard for these groups; the APE 25/40 installs without reworking the connection.
• Pump group NG-48 with mixer (130 mm) — the pump is perfectly compatible in terms of installation dimensions.
• Replacement of a pump with equivalent 130 mm parameters and 1″ connection — without reworking the pipework.
• Heat pump system: the ECM motor minimises consumption alongside a HP. More details: Termojet heat pumps.

Why ECM Is Better Than 3-Speed

A conventional asynchronous pump consumes 80–100 W continuously — one of three fixed speeds, even when the system is barely loaded. The permanent-magnet ECM motor with built-in frequency converter regulates speed smoothly: minimum 5 W at low load, maximum 25 W at full load. Over a heating season the difference on the electricity bill is significant. Wet-rotor technology eliminates shaft seals and external lubrication: the heat-transfer fluid cools and lubricates the rotor directly — the pump requires no maintenance whatsoever.

APE 25/40 and Heat Pump System

A heat pump produces heat-transfer fluid at 30–55 °C — the optimal temperature for underfloor heating. The APE 25/40 in Δp-v mode precisely adapts to the varying HP load without creating hydraulic stress. Every extra watt from the pump reduces the real COP of the system — ECM-class consumption is not an option here, it is a necessity. See compatible equipment at tjheatpump.com.ua.

Frequently Asked Questions

Will 4 m head be enough for my underfloor heating system?
4 m head covers underfloor heating circuits in houses up to 100–120 m² with standard pipes. For systems with more circuits or longer loops, check the hydraulic resistance — if needed, the APE 25/80 with 8 m head is suitable.

Which Termojet pump group to choose for the APE 25/40?
APE 25/40/130 mm is compatible with NG-46 and NG-48 with mixer. All groups in the catalogue are available on the Termojet pump groups page.