Hot water boiler TSR-HWB 6/9 is an electric floor heating exchanger that heats the circulating water of a hydronic underfloor heating system on a construction site. The element rating is selectable at 6 kW or 9 kW, and the output is adjustable steplessly from 500 watts upwards. The flow temperature is set between 0 and 50 °C. One unit heats up to 250 square metres of floor area.

Who is the Hot water boiler TSR-HWB 6/9 for?

The unit is intended for temporary heating and drying of a concrete slab on a site where the permanent heating system is not yet connected.

It also serves as a construction-phase boiler in new builds, in renovation and extension projects, and as a backup boiler while the main boiler is being serviced. The same unit suits garages, holiday homes, animal shelters and industrial premises.

As a supplementary heat source it tops up a heat pump during the coldest spells.

Hot water boiler TSR-HWB 6/9 in concrete drying

The drying of a concrete slab determines when the floor can be surfaced, and surfacing determines the handover. When the slab is heated from below through hydronic underfloor heating, the drying proceeds evenly across the whole area.

The flow temperature is set between 0 and 50 °C to match the work stage, so the slab is not heated too fast or too hot.

Finland’s national energy agency Motiva publishes background on moisture control and energy efficiency in construction.

Hot water boiler TSR-HWB 6/9 arrives ready to connect

Everything needed is fitted at the factory: an electronic circulation pump, a 4-litre expansion vessel and a manifold with a safety valve, a pressure gauge, a filling tap and an air vent.

The heating element is built from pressure-equipment tubing and pressure-tested to 4 bar of working pressure. The enclosure is white sheet steel.

No separate components need to be sourced or assembled on site – the unit is connected to the pipework and the power supply and it is ready to run.

Hot water boiler TSR-HWB 6/9 – technical data

Element rating	6 kW or 9 kW (two-step)
Output adjustment range	500–9000 W
Voltage	400 V
Temperature control	0–50 °C
Heated floor area	up to 250 m²
Expansion vessel	4 litres
Test pressure	4 bar
Circulation pump	Electronic, compliant with EU directives
Manifold	Safety valve, pressure gauge, filling tap, air vent
Pipe connections	2 or 4 × R25 internal thread
Element connection	1 × R50 internal thread
Centre distance, pipe connections	300 mm
Insulation	30 mm pipe insulation
Element enclosure	White sheet steel
Dimensions (without element)	150 × 150 × 445 mm
Installation	Wall mounted, brackets or steel plates included
Product number (MPN)	801030012

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Wall mounted, no fixed structures needed

The Hot water boiler TSR-HWB 6/9 is mounted on a wall with the brackets or steel plates supplied with it. The mounting plate has a carrying slot, so the unit is easy to move from one site to the next.

The pipe connections are R25 internal threads at a centre distance of 300 mm, so they mate with standard components. Two or four connections are available, depending on how many circuits are connected.

The compact 150 × 150 × 445 mm body fits a cramped plant room as well.

Where the Hot water boiler TSR-HWB 6/9 is used

Typical applications:

• hydronic underfloor heating on site
• drying a cast foundation or concrete slab
• construction-phase boiler in a new build
• renovation and extension projects
• detached houses, holiday homes, cabins and garages
• animal shelters and industrial premises
• supplementary heat for a heat pump
• backup boiler while the main boiler is serviced

What does 6/9 mean in the model name?

It refers to the two ratings of the heating element, 6 kW and 9 kW. The output is chosen to match the site’s demand and the available electrical supply, so the same unit moves between projects of different sizes.

The lower step heats a smaller area or runs the unit as supplementary heat. The higher step speeds up warming the slab when the schedule is tight.

Output is also adjustable steplessly from 500 watts upwards, so the heating can be fine-tuned to the work stage. If the demand is known and the supply is not a constraint, the fixed nine kilowatt model is enough: see the fixed 9 kW model.

Choosing the right heating solution

This unit heats the circulating water of the floor circuit, so the heat comes from under the slab. It suits sites where the underfloor heating pipework is already installed.

If you need warm air for a large space, look at the TSR V-Heat 400 kW mobile heat exchanger. The full hydronic range is on the hydronic heating page.

On larger sites several units run in parallel, and the heated area grows accordingly.

Frequently asked questions

How large an area does the Hot water boiler TSR-HWB 6/9 heat?

One unit heats up to 250 m² of floor area. On larger sites several units are used in parallel.

What is the output and voltage?

The element rating is selectable at 6 kW or 9 kW, and the output is adjustable steplessly from 500 watts upwards. The voltage is 400 V.

How hot does the flow water get?

The flow temperature is adjusted steplessly between 0 and 50 °C.

What is the difference between the TSR-HWB 9 and TSR-HWB 6/9?

The body, the pipework and the dimensions are the same. The difference is the heating element: see the fixed 9 kW model.

What comes fitted as standard?

An electronic circulation pump, a 4-litre expansion vessel and a manifold with a safety valve, a pressure gauge, a filling tap and an air vent. The element is pressure-tested to 4 bar.

What pipe connections does it have?

Two or alternatively four R25 internal threads at a centre distance of 300 mm. The heating element has its own R50 internal thread.

How is the unit installed?

On a wall, with the brackets or steel plates supplied. The mounting plate has a carrying slot for moving it.

What is the product number (MPN)?

The product number, or MPN, is 801030012.

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