The Biasi Dina 25C is a wall-hung condensing combi boiler delivering 25 kW of output for both central heating and instantaneous domestic hot water. Manufactured in Italy to Biasi's exacting standards, the Dina combines Gas Adaptive Technology, a stainless steel premix heat exchanger, and a compact 706 × 400 × 268 mm footprint — making it one of the most space-efficient condensing combis on the market. This pack pairs the boiler with the Biasi Horizontal Flue Kit (Ø 60/100 mm), the most common flue choice for installations where the flue exits directly through an external wall. The Dina is 20% Hydrogen Ready, backed by a 5-year manufacturer warranty (extendable with Biasi Connect), and carries an ErP Energy Class A rating as standard — upgradable to A+ with an optional weather-compensation kit.
12.5 L/min
DHW Flow (ΔT 30K)
Installation — Gas Safe Engineer Required. This appliance must be installed and commissioned by a Gas Safe Registered Engineer in accordance with the current Gas Safety (Installation & Use) Regulations, BS 7671 and Biasi's installation manual. LPG conversion requires the appropriate Biasi conversion kit and must only be carried out by a competent engineer.
Horizontal Flue — Max Length 10 m (Ø 60/100 coaxial). The included horizontal flue kit provides a standard straight-through wall exit. Each 45° elbow deducts 0.5 m and each 90° elbow deducts 1 m from the permitted maximum. For longer or more complex routes, additional Biasi flue extensions and elbows are required. The Offset Flue Adaptor (10999.1492.0) is available where central alignment to the boiler is needed.
Pack Contents: Biasi Dina 25C combi boiler + Horizontal Flue Kit (Ø 60/100 mm, Part No. 10999.0387.1). All isolation valves with pre-formed copper pipes, condensate drain adaptor, wall mounting plate, paper template, power supply cable, user/installation/service manual, and warranty documentation are included with the boiler.
Gas Adaptive Technology
The eGarc combustion control system continuously analyses the flame signal and adjusts gas valve and fan to maintain optimal CO₂ levels at all times — regardless of supply gas quality or seasonal variation. A single boiler model covers both Natural Gas and LPG, simplifying stock and ordering.
Stainless Steel Heat Exchanger
The large-section oval coil primary heat exchanger is produced from high-grade stainless steel for long-term corrosion resistance. Its patented geometry promotes self-cleaning, reduces pressure losses, and makes system flushing straightforward — well suited to both new and retrofit installations.
Compact Dimensions
At just 706 × 400 × 268 mm and 31.5 kg, the Dina is among the most compact 25 kW combis available — ideal for kitchen cupboards, utility rooms, and tight airing cupboards. The shallow 268 mm depth further simplifies cupboard-mount installations.
Intuitive Digital Control Panel
The backlit LCD display provides clear readout of DHW and CH set temperatures, live system pressure, and fault diagnostics. Summer/Winter/Off mode selection and separate CH and DHW temperature adjustment are managed via simple push buttons — straightforward for end users and installers alike.
20% Hydrogen Ready
The Dina is certified for operation on gas mixtures containing up to 20% hydrogen by volume, meeting the UK's commitment to blending hydrogen into the national gas grid. No hardware changes are needed to accommodate future grid hydrogen content up to this level.
Wi-Fi Ready / Biasi Connect
The Dina is Wi-Fi ready for connection to the Biasi Connect app, enabling remote monitoring, temperature adjustment, and fault-code visibility from a smartphone. The optional modulating weather-compensation probe also unlocks the full ErP A+ energy class.
Technical Specifications — Biasi Dina 25C
| Nominal heat input — heating / DHW |
21.0 / 26.0 kW |
| Minimum heat input — heating / DHW |
5.2 / 5.2 kW |
| Max usable power 60°/80°C (heating / DHW) |
20.7 / 25.6 kW |
| Max usable power 30°/50°C (condensing) |
22.6 / 28.0 kW |
| Efficiency nom. 60°/80°C |
98.58 % |
| Efficiency nom. 30°/50°C |
107.8 % |
| Efficiency at 30% load (30°/50°C) |
109.75 % |
| ErP seasonal efficiency ηs |
94 % |
| DHW flow rate ΔT 25K / ΔT 35K |
14.9 / 10.4 L/min |
| Specific DHW flow rate ΔT 30K (EN 625) |
12.5 L/min |
| Min / Max DHW temperature |
33 / 55 °C |
| Min / Max DHW pressure |
0.3 / 10.0 bar |
| Min / Max CH temperature |
25 / 80 °C |
| Min / Max CH pressure |
0.3 / 3.0 bar |
| Available pump head (at 1000 L/h) |
430 mbar |
| Expansion vessel capacity |
7 litres |
| NOx class / weighted NOx |
Class 6 / 28 mg/kWh |
| Voltage / power at nominal input |
230 V~ / 94 W |
| Stand-by power draw |
3 W |
| Ingress protection |
IPX5D |
| Max coaxial flue length Ø 60/100 mm |
10 m |
| Max twin flue length Ø 80+80 mm |
40 m |
| Dimensions H × W × D |
706 × 400 × 268 mm |
| Weight |
31.5 kg |
| Water content |
2.0 litres |
| Gas type |
Natural Gas G20 / LPG G31 |
| Warranty |
2 years manufacturer (extendable via Biasi Connect) |
Frequently Asked Questions
What size property is the Biasi Dina 25C suited to?
The 25C is well matched to small to medium-sized properties with up to two bathrooms and a moderate hot water demand. With a specific DHW flow rate of 12.5 L/min (EN 625), it comfortably supplies a shower and washbasin simultaneously. For larger homes or high-demand properties, consider the Dina 30C or 35C.
Does the horizontal flue kit cover a standard wall installation?
Yes. The included Horizontal Flue Kit (10999.0387.1, Ø 60/100 mm) is suitable for a direct through-wall exit up to approximately 1 m from the boiler. For longer horizontal runs — up to a maximum of 10 m — additional 1 m or 2 m extensions (10999.0388.1 / 10999.0928.0) are required. Each 90° elbow reduces the maximum permitted run by 1 m.
Can the Dina 25C be converted from Natural Gas to LPG on site?
Yes — LPG conversion is possible using the appropriate Biasi LPG conversion kit. The Gas Adaptive Technology also means no recalibration is required after gas-type changes via the CAF (automatic calibration) function in the service menu. All gas conversions must be performed by a Gas Safe Registered Engineer.
What is required to achieve ErP A+ energy class?
The Dina 25C achieves ErP Energy Class A as supplied. To reach the higher A+ classification, a modulating room thermostat and an external weather-compensation temperature probe must be fitted. The probe connects to the E1–E2 terminals on the PCB and allows the boiler to continuously adjust flow temperature in response to outdoor conditions, minimising energy consumption.
How does the annual service reminder work?
The Dina displays the months remaining to the next service in the Info mode on the control panel. After a service, the Gas Safe engineer resets the reminder period (typically 12 months) via the Maintenance menu under access code 6683. This keeps the boiler compliant with the manufacturer's service schedule and maintains the warranty.
Is system water treatment required at installation?
Yes. Biasi requires the central heating system to be thoroughly flushed and dosed with a suitable inhibitor before commissioning. The installation of a magnetic filter is also strongly recommended to protect the boiler's heat exchanger and pump. Failure to comply with water treatment requirements may affect the manufacturer warranty.
