Condensing boiler · New equipmentWolf CGB-2K 20

Wolf CGB-2K 20 boiler

VAT includedIn stock

The Wolf CGB-2K 20 (ref. 8615054) is a wall-mounted mixed condensing boiler: it provides heating and produces domestic hot water within the unit through an integrated stainless steel plate heat exchanger. Reference for the boiler alone. Control, connections, flue, and installation to be confirmed. VAT and mainland shipping included.

Heating power (80/60 °C): 18.9 kW
Specific flow rate for domestic hot water (ΔT 30 K): 10.3 l/min
Dimensions (height x width x depth): 790 x 440 x 378 mm

Condensing boiler

The model, at a glance

Wolf CGB-2K 20: 18.9 kW of heating at 80/60 °C, instantaneous domestic hot water, and 790 x 440 x 378 mm. Technical data, comparison, and PDF in Spanish.

Heating power (80/60 °C): 18.9 kW
Specific flow rate for domestic hot water (ΔT 30 K): 10.3 l/min
Dimensions (height x width x depth): 790 x 440 x 378 mm

Read the full description and what it includes.

In heating, it delivers 18.9 kW of nominal thermal power at 80/60 °C and 20.4 kW at 50/30 °C. At 80/60 °C, the minimum modulating power is 3.8 kW with natural gas and 6.8 kW with LPG G31, so the selection must start from the calculated thermal load and the actual temperature of the installation.

DHW is produced when a tap is opened, without a storage tank. The normalized specific flow rate is 10.3 l/min at ΔT = 30 K; it should not be confused with the factory-adjusted flow rate, which ranges from 2.0 to 6.5 l/min. The DHW temperature is adjusted between 45 and 65 °C. The body measures 790 x 440 x 378 mm and the 10 l expansion vessel belongs to the heating system, it does not store water for showers.

What is included in the purchase?

Boiler reference only. Control, connections, exhaust and installation to be confirmed.

Price including VAT and shipping to mainland Spain. Installation, adaptations, and commissioning are valued separately.

Consult the manufacturer's PDFs ↓

Guide

What to check before installing this boiler

The choice of equipment does not replace the inspection of the installation by a qualified professional.

Confirm the model and commercial reference, the type of gas, and the supply configuration in the manufacturer's documentation.
Ask a qualified installer to assess the heating and domestic hot water demand; compare measured flow rates at the same temperature difference.
Check dimensions, connections, flue gas evacuation, condensate drainage, and controls compatible with the existing installation.
Confirm the included accessories and the delivery time before scheduling the installation. The online purchase of the equipment does not include installation or commissioning.

Technical data

Technical data of Wolf CGB-2K 20 boiler

Brand: Wolf
Model: Wolf CGB-2K 20 boiler
Status: New
Supply scope: Boiler reference only. Control, connections, exhaust and installation to be confirmed.
Shipping: Included in mainland Spain. Please confirm the deadline.
Commercial reference: 8615054

Specifications and dimensions of the model

Compare each magnitude under its testing conditions: heating, domestic hot water, efficiency, and dimensions.

Maximum useful power (80/60 °C): 18.9 kW
Heating
Maximum useful power (50/30 °C): 20.4 kW
Heating
Minimum power (80/60 °C, natural gas): 3.8 kW
Heating
Minimum power (80/60 °C, LPG G31): 6.8 kW
Heating
Maximum heating pressure: 3 bar
Heating
Heating expansion vessel: 10 l
Heating
Production of domestic hot water: Instantaneous, without integrated domestic hot water accumulator
Hot water
Maximum useful power in domestic hot water: 22.2 kW
Hot water
Specific flow rate of domestic hot water (ΔT 30 °C): 10.3 l/min
Hot water
Domestic hot water flow rate with factory limiter: 2.0–6.5 l/min
Hot water
Adjustable domestic hot water temperature: 45–65 °C
Hot water
Maximum domestic hot water pressure: 10 bar
Hot water
Dimensions (height × width × depth): 790 × 440 × 378 mm
Dimensions and connections
Weight: 35 kg
Dimensions and connections
Heating connections: G 3/4 inches
Dimensions and connections
Domestic hot water connections: G 3/4 inches
Dimensions and connections
Gas connection: R 1/2 inch
Dimensions and connections
Concentric flue connection: 60/100 mm
Dimensions and connections
Electrical supply: 230 V / 50 Hz
Dimensions and connections
NOx emissions class: 6
Efficiency and consumption
Standby power consumption: 3 W
Efficiency and consumption
Maximum electrical consumption: 63 W
Efficiency and consumption
Degree of protection: IPX4D
Efficiency and consumption
Nominal ErP power (Prated): 19 kW
Efficiency and consumption
Heating energy class: A
Efficiency and consumption
Seasonal heating efficiency: 93 %
Efficiency and consumption
Domestic hot water load profile: XL
Efficiency and consumption
Energy class of domestic hot water: A
Efficiency and consumption
Efficiency of domestic hot water: 85 %
Efficiency and consumption
Normalized annual heating consumption (QHE): 10568 kWh/year
Efficiency and consumption
Normalized annual fuel consumption in domestic hot water (AFC): 17 GJ/year
Efficiency and consumption
Sound power level indoors (LWA): 47 dB
Efficiency and consumption

Manufacturer's sources

PDF and documentation of the model

Original documents, unmodified. Refer to the installation plan and the conditions of each data point before selecting the equipment.

The gallery sheets are summaries of Uniclima based on these documents. The external volume diagram does not represent connections, accessories, or service distances.

Frequently Asked Questions

Frequently asked questions: condensing boilers 8615054

Does the Wolf CGB-2K 20 work for an apartment of 100 m²?

It can meet the heating demand of the following indicative example: if we assume 80 W/m², an apartment of 100 m² would require 100 x 80 = 8,000 W = 8 kW. This demand is within the range of 3.8 to 18.9 kW at 80/60 °C with natural gas. If on mild days the demand drops below 3.8 kW, the boiler cannot modulate continuously below that minimum and may operate in cycles. The 80 W/m² is an assumption of the example, not a recommendation of surface area from Wolf; the installer must calculate the actual heat losses according to climate, insulation, and ventilation, and check the emitters and the demand for domestic hot water before selecting it.

Can it maintain two showers at the same time?

It is not advisable to choose it to ensure two showers of 8 l/min each. They would add up to 16 l/min at ΔT = 30 K, exceeding its normalized specific flow rate of 10.3 l/min. Additionally, Wolf indicates a factory setting of the limiter from 2.0 to 6.5 l/min of hot water at the outlet of the unit; that figure is not the mixed flow rate in the shower. The cold water added at the faucet, the inlet temperature, the setpoint, and the pressure modify the flow rate in use. It cannot be promised that a specific shower will work just by comparing it to the normalized flow rate: the entire system must be checked in the installation.

Does it have a domestic hot water accumulator or just an expansion vessel?

It has instantaneous domestic hot water production through a plate heat exchanger and does not declare an integrated sanitary accumulator. The 10 l expansion vessel belongs to the heating circuit: it absorbs the volume variations of the heating water and does not reserve water for showers.

What space and connections need to be checked before installing it?

The body measures 790 x 440 x 378 mm, in height x width x depth. Additionally, it is necessary to verify the service space, the piping layout, the drainage, and the maintenance access according to the installer’s instructions; the dimensions of the body alone do not certify that an existing opening is valid.

When to choose the CGB-2K 20 and when to consider the CGB-2K 24?

With natural gas and at 80/60 °C, the CGB-2K 20 operates between 3.8 and 18.9 kW; the CGB-2K 24, between 4.8 and 23.8 kW. If the calculated losses are covered by the 20, its lowest minimum can be useful when little heat is needed. It is advisable to consider the 24 if more heating power or higher domestic hot water flow is required: it offers 13.0 compared to 10.3 l/min, both at ΔT = 30 K. This increase in flow does not guarantee two showers of 8 l/min simultaneously, which would total 16 l/min at the same temperature difference. The specific flows are normalized values, not the factory limits: these are 2.0–6.5 l/min for the 20 and 2.0–8.0 l/min for the 24, before mixing with cold water at the tap.

What efficiency and noise level are listed for the CGB-2K 20?

The ErP sheet declares class A for heating and class A for domestic hot water, load profile XL, seasonal efficiency of 93% in heating and 85% in domestic hot water, with an indoor acoustic power of 47 dB. These are standardized values of the product and not a prediction of the bill or a measurement of noise in a specific home.

Does the price include installation and shipping?

Includes VAT and shipping to mainland Spain. Installation and adaptations are valued separately. Reference for the boiler only. Control, connections, exhaust, and installation to be confirmed.