Vitocal 250-A PRO outdoor unit, three-quarter view
Vitocal 250-A PRO outdoor unit, front view
Vitocal 250-A PRO outdoor unit with its indoor control unit
Vitocal 250-A PRO, inside the outdoor unit with fan and compressor
Vitocal 250-A PRO outdoor and indoor units in a showroom setting
Vitocal 250-A PRO installed next to an office building

Viessmann Vitocal 250-A PRO R290 monobloc air-to-water heat pump, 39.5 kW

Regular price€56.172,72
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Your guarantees

  • Rights intact: 14 days of withdrawal from receipt for most products—subject to the legal exceptions you will see below, such as goods made to your specifications—and a 3-year legal warranty of conformity, under the terms of the TRLGDCU.
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  • If you are thinking of returning it, keep it as you received it: without installing or activating it, with its seals, accessories, and packaging intact. This is how to ensure a full refund, without deductions.
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  • Delivery of bulky goods: delivery is made to the curb. B2C: transport risk is ours until physical delivery (art. 66 ter); we recommend noting visible damages on the delivery note and notifying us of breakages within 24-48 hours with photographs to activate the insurance. B2B: inspection and notation on the delivery note are mandatory; hidden damages must be reported within 24 hours (art. 366 CCom). Unjustified rejection or incorrect shipping information will entail the actual outbound and return costs (approx. €85-550 for heavy machinery).

Made to your measure (Advanced Pre-Assembly)

  • If your order includes equipment, racks, hydraulic assemblies, or technical rooms made or configured according to your specifications (permanent joints, custom cuts or wiring, parameterization, pressure testing), these are custom goods without the right of withdrawal from the conclusion of the contract (art. 103.c TRLGDCU; CJEU Case C-529/19), which is informed before purchasing and documented in the signed Order Note. A test you request without permanent modification retains your right of withdrawal, with only the actual loss of value caused by that test being deducted. Would you prefer to receive it tested, configured, and ready to connect, without assuming these risks? Contract our Advanced Pre-Assembly or the prior technical audit.

If you are purchasing as a business or professional (B2B)

  • The transaction is governed by the Commercial Code: firm sale, without the right of withdrawal; notification of defects within 4 days (apparent) / 30 days (hidden), arts. 336 and 342. Q-TECH acts as a distributor and excludes indirect damages, loss of profit, and data loss, limited to the price of the equipment, without prejudice to the manufacturer's commercial warranty.

Product warnings v1.0 · June 2026. Information summary; the complete and binding conditions are those published at q-tech.es.

Air-to-water heat pump up to 39.5 kW for apartment blocks, hotels and commercial buildings

The Viessmann Vitocal 250-A PRO is an air-to-water heat pump for large buildings that provides heating, cooling and domestic hot water with the natural refrigerant R290. Q-Tech integrates it into your plant room and can deliver it inside a pre-assembled plant room, tested in our workshop and ready to connect on site.

Summary

TypeMonobloc air-to-water heat pump for outdoor installation, with an indoor control unit
Brand and modelViessmann Vitocal 250-A PRO, model AWO-AC-AF 251.A40 (reference Z027591)
UseHeating, cooling and domestic hot water in residential, commercial and business buildings
Output21.5 kW rated at A7W35, modulating from 8.0 to 39.5 kW
EfficiencyCOP 5.32 at A7W35; energy class A+++ at 35 °C and A++ at 55 °C
RefrigerantR290 (propane), 3.3 kg, GWP 0.02
Warranty5-year Viessmann full warranty, subject to its general terms of sale
Q-Tech installationIntegration in a pre-assembled plant room or on-site by an Expert Technician

What is the Vitocal 250-A PRO?

The Vitocal 250-A PRO by Viessmann is a monobloc air-to-water heat pump for large buildings that modulates from 8.0 to 39.5 kW with R290 refrigerant. The outdoor unit draws energy from the air. An indoor control unit manages the system.

Natural refrigerant and quiet operation

Viessmann calls the use of the natural refrigerant R290, with a global warming potential of 0.02, Climate Protect. The outdoor unit has a sound power level of 58 dB(A) under ErP and a Super Silent mode for noise-sensitive locations. Viessmann states fast defrosting and the use of surplus power from a photovoltaic system.

What problem does it solve?

An apartment block, a hotel or an office building needs heating, cooling and hot water from a single system. Splitting that output across many small units multiplies connections, control panels and maintenance points in the plant room.

The Vitocal 250-A PRO concentrates up to 39.5 kW in one outdoor unit and delivers a flow temperature of up to 70 °C, so it works with radiators as well as underfloor heating. An output chosen without a heat load calculation leads to short cycling or a lack of heat on cold days, so it should be sized as part of a design.

Viessmann diagram of a building with two Vitocal 250-A PRO units, Vitocell cylinders, Vitotrans 353 and Vitovolt 300 solar PV

The Viessmann diagram shows the Vitocal 250-A PRO in an apartment building with hot water storage, instantaneous domestic hot water production and a photovoltaic system.

Technical data

Rated heating output A7W3521.5 kW (COP 5.32)
Output range A7W358.0 to 39.5 kW
Heating output A-7W3525.0 kW
Rated heating output A7W5520.2 kW (COP 3.59), range 8.3 to 37.8 kW
Cooling output A35W1822.9 kW (EER 4.7)
Cooling output A35W724.1 kW (EER 2.85)
Seasonal efficiency (ηs)191% at 35 °C and 150.7% at 55 °C
Heating SCOP4.89 at 35 °C and 3.84 at 55 °C
Energy classA+++ at 35 °C and A++ at 55 °C
Maximum flow temperature70 °C
RefrigerantR290, 3.3 kg, GWP 0.02
Outdoor unit sound power (ErP)58 dB(A)
Safety valve3 bar
Water connections1½ inch thread
Outdoor unit dimensions1,900 mm long, 940 mm deep and 1,570 mm high
Outdoor unit weight565 kg
Indoor control unit600 mm wide, 700 mm high and 250 mm deep; 26 kg
Made inBerlin (Germany)
Viessmann referenceZ027591 (AWO-AC-AF 251.A40)

Compatibility and limits

  • Because of its weight, the outdoor unit stands on the Viessmann damping base or floor console, on a firm surface.
  • Viessmann offers the magnetic sludge separator in 1½ and 2 inch sizes to protect the circuit.
  • With a single unit, the Viessmann pump module is not required; in a cascade, Viessmann specifies one module per outdoor unit.
  • Official commissioning is carried out by Viessmann Technical Service or an installer trained by Viessmann.
  • Installation and certification require a licensed installation company.

When this product is not the right choice

  • For a single-family home, a residential heat pump such as the Vitocal 150-A or the Vitocal 250-A Black better matches the demand.
  • If the system needs a flow temperature of up to 75 °C, the Vitocal 200-A ie is the alternative in the range.
  • If you only need domestic hot water, a DHW heat pump such as the Vitocal 262-A is simpler.

Frequently asked questions

What output does the Vitocal 250-A PRO deliver?

It delivers 21.5 kW rated at A7W35 and modulates from 8.0 to 39.5 kW. At −7 °C outdoors with 35 °C water it delivers 25.0 kW.

Does it produce domestic hot water?

Yes, with a Vitocell cylinder or a Vitotrans 353 fresh water station, as in the Viessmann diagram. The flow temperature reaches 70 °C.

Do I need the pump module?

Not with a single unit. Viessmann offers it in an outdoor (ZK07448) and an indoor (7987055) version, with a KSB Calio 30-120 pump, mixer and filter.

What is the delivery time?

Made to order: we will confirm the lead time before preparing your order. Because of its weight, transport is quoted separately.

Can I install it myself?

No. It needs a design, a licensed installation company and official Viessmann commissioning; Q-Tech integrates it and carries out the pre-commissioning check.

Q-Tech installation and support

Q-Tech delivers the Vitocal 250-A PRO as part of a pre-assembled plant room: assembled, configured and tested in our workshop, with safety and operation tests. It arrives on site ready to connect, and the final connection is made by the site installer or Q-Tech. That means fewer site visits and fewer companies working in the plant room at the same time. See how it works in Advanced Pre-Assembly and the Expert Technician workshop pre-assembly service.

If another company installs the heat pump, or it is integrated into an existing system, Q-Tech first carries out a verification visit with the on-site hourly Expert Technician service. For sizing questions, book a technical call or message us on WhatsApp. More units in commercial and industrial heat pumps.

Q-Tech VDI 2035 calculator

Check whether the water in your heating system meets the VDI 2035 guideline (Part 1, 2021). Enter the output, the system volume in litres and the hardness and conductivity of your mains water: the calculator gives you the verdict and the three key figures for filling or topping up the circuit. If you need it, we will send you the full report.

Guidance only: check the manufacturer's requirements.

VDI 2035 calculator: check whether your system water meets the guideline. Open the calculator

Documentation

Availability and lead times: made to order. We will confirm the lead time before preparing your order. Because of its weight, transport is quoted separately.

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