The Blow Air S4-3S water fan heater offers a nominal heating output of 50.1 kW (3 speeds) / 38.5 kW (2 speeds) / 27.5 kW (1 speed), a maximum air flow of 3,350 m³/h (3 speeds), a throw of 18 m, 2 heat exchanger rows, a water capacity of 2.0 dm³, and a powder-coated galvanized steel casing. Distributed in Italy by Krollit.
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Heating output (speed 3/2/1): 50.1 / 38.5 / 27.5 kW
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Heating capacity range: 4.17–66.2 kW
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Air flow (speed 3/2/1): 3,350 / 2,250 / 1,400 m³/h
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Isothermal throw: 18 m
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Heat exchanger rows: 2
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Water capacity: 2.0 dm³
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Casing: Powder-coated galvanized steel
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Weight: approx. 29 kg
Who uses the S4-3S and for what
The Blow Air S4-3S water fan heater is an air heater connected to the central hydronic system: it uses hot water from the existing heating system (boiler, heat pump, combined heat and power unit) to heat the ambient air via a 2-row heat exchanger. With 50.1 kW of heating power at maximum speed and an air flow of 3,350 m³/h, it is dimensioned for large industrial environments (over 500 m²). The 3-speed fan allows power modulation according to need. Krollit customers use it in warehouses, mechanical workshops, storage facilities, and logistics centers that already have a hydronic system and are looking for an efficient distribution terminal.
Who is the Blow Air S4-3S for
| Profile |
Compatibility |
Reason |
| Home use |
Not suitable |
Dimensioned for industrial environments. For home use, consider wall-mounted fan coil units with lower power. |
| Warehouse / workshop with hydronic system |
Ideal |
50.1 kW and 3,350 m³/h air flow: dimensioned for heating large industrial environments. Connection to the existing system. |
| Autonomous system without hydronic |
Not suitable |
The water fan heater requires an existing hydronic system (boiler or heat pump). For environments without a hydronic system, consider electric or gas fan heaters. |
Not suitable for: environments without a central hydronic system; home use; installation without a specialized technician for the hydraulic connection.
Thermal and air handling data
| Specification |
Value |
| Nominal heating output (speed 3) |
50.1 kW |
| Nominal heating output (speed 2) |
38.5 kW |
| Nominal heating output (speed 1) |
27.5 kW |
| Heating capacity range |
4.17–66.2 kW |
| Maximum air flow (speed 3) |
3,350 m³/h |
| Maximum air flow (speed 2) |
2,250 m³/h |
| Maximum air flow (speed 1) |
1,400 m³/h |
| Isothermal throw |
18 m |
Construction and hydraulic data
| Specification |
Value |
| Number of heat exchanger rows |
2 |
| Water capacity |
2.0 dm³ |
| Maximum fluid temperature |
120 °C |
| Casing |
Powder-coated galvanized steel |
| Fan |
3 speeds – IP 54 – ErP 2015 |
| Indicative dimensions (L × W × H) |
700 × 500 × 430 mm |
| Weight |
approx. 29 kg |
Compliance
| Specification |
Value |
| Fan directive |
ErP 2015 |
| Fan protection |
IP 54 |
Logistics
Shipping 5–9 business days (7 days for the South). Spare parts available with 3–5 business day shipping. Customer support in Italian available.
Frequently Asked Questions
What water temperature is needed for the S4-3S?
The fan heater is designed to operate with a maximum fluid temperature of 120 °C, compatible with any standard central hydronic system (gas boiler, heat pump, district heating). The nominal heating output is usually measured at a supply/return temperature of 80/60 °C: at lower temperatures (e.g., 60/40 °C with heat pumps), the effective power is proportionally reduced.
What is the difference between S1, S2, S3, and S4?
The four models differ in heating power and air flow: S1 (50.1 kW, 3,350 m³/h), S2 (23.4 kW, 2,000 m³/h), S3 (36.9 kW, 1,800 m³/h), S4 (50.1 kW, 3,350 m³/h). The choice depends on the room volume and thermal dispersion. A heating and plumbing technician can correctly size the model for the specific site.
Does the hydraulic connection require a specialized technician?
Yes. Connection to the hydronic system (supply and return pipes, control valve, air vent) requires a qualified heating and plumbing technician. Krollit provides complete technical documentation and an installation manual in Italian. Installation is not included in the supply.
Is the mounting bracket included?
The mounting bracket for wall or ceiling fixing is available as a dedicated accessory. Please check with Krollit for the availability of the specific bracket for the S4-3S model at the time of order.
Is the fan compatible with thermostats and automation systems?
Yes. The S series fan heaters can be equipped with accessories for automated control (thermostats, speed controllers, BMS systems). Contact Krollit for available automation options for the S4-3S.
