Circulator pump Termojet AUTO energy-saving APM 25/8/180 mm

Termojet AUTO APM 25/8/180 mm circulator pump — a high-performance energy-saving circulator with an ECM permanent-magnet motor and wet rotor for heating systems with elevated flow-rate requirements. Installation length 180 mm, threaded connection 1¼″ BSP (female union nut), power consumption 5–80 W, maximum head 8 m, flow rate up to 8 m³/h.

Technical Specifications

AUTO Operating Modes

Constant differential pressure (Δp-c). The pump maintains a set pressure difference between the supply and return pipes constantly, regardless of the number of open valves. Δp-c mode is a reliable choice for radiator systems with a large number of emitters and thermostatic valves on each one.

Proportional differential pressure (Δp-v). The differential pressure decreases together with the flow rate at partial system load. Δp-v mode minimises noise and consumption — optimal for mixed systems (radiators + underfloor heating) and for pump groups with a mixing valve.

Applications

• Large radiator systems in buildings from 200 m², where high flow rate (up to 8 m³/h) is required at moderate head.
• Pump group NG-51.150 (180 mm) — the APM 25/8 is the standard pump for this group: installation length 180 mm and 1¼″ BSP connection match exactly.
• Pump group NG-52.150 (180 mm) — full compatibility for systems with an insulated pump group.
• Replacement of an old 3-speed pump with 1¼″ thread and installation length 180 mm — without modifying the pipework.
• Heat-pump system with a multi-zone manifold: Termojet heat pumps.

Why ECM Is Better Than 3-Speed

An old asynchronous 1¼″ pump consumes 80–120 W at any of its three fixed speeds — even in the off-season. The ECM motor of the APM 25/8 regulates speed smoothly from minimum to maximum: 5 W in base mode, 80 W at peak flow. Wet-rotor technology: the heat-transfer fluid cools and lubricates the rotor without shaft seals or external lubrication. The pump requires no maintenance throughout its entire service life.

APM 25/8 and a Heat-Pump System

The high flow rate of up to 8 m³/h allows the APM 25/8 to serve a manifold with multiple underfloor heating zones connected to a heat pump. Δp-v mode provides automatic adaptation to the variable load of the heat pump without water hammer. See comprehensive solutions at tjheatpump.com.ua.

Frequently Asked Questions

Why APM 25/8 and not APE 25/80 with the same 8 m head?
The APM 25/8 has a significantly higher flow rate — up to 8 m³/h versus 3.6 m³/h for the APE 25/80. The 1¼″ BSP threaded connection is also larger, ensuring a lower fluid velocity and lower hydraulic losses at high flow rates.

Can the APM 25/8 be installed instead of another manufacturer's 1¼″ pump?
Yes. The installation length of 180 mm and the 1¼″ BSP connection are the standard for pumps of this class. Installation requires no adapters and no pipe modification. Also see the Termojet pump group catalogue.