| Model | Units | Combi 25 Eco |
| Boiler only code | | 5116329 |
| Controls | | |
| Adjustable CH temperature | | Yes |
| User adjustable DHW temperature | | Yes |
| Operating mode selector switch | | Yes |
| LED operating / fault status display | | Yes |
| Integral 24 hr electro-mechanical timer | | Optional |
| Integral 7 day electronic timer | | Optional |
| Wireless programmable room thermostat | | Optional |
| Gas | | |
| Natural gas | | Yes |
| Inlet supply pressure (Natural gas) | mbar | 20 |
| Gas rate | m3/hr | 2.76 |
| Heat input (maximum) | kW | 28.92 |
| Heat input (minimum) | kW | 8.68 |
| Heat output (maximum) condensing | kW | 26.95 |
| Heat output (minimum) condensing | kW | 8.37 |
| Heat output (maximum) non-condensing | kW | 25.94 |
| Heat output (minimum) non-condensing | kW | 7.61 |
| Domestic hot water flow rate (maximum) @ 35°c rise | litres/min | 10.2 |
| Domestic hot water flow rate (minimum) | litres/min | 2 |
| Seasonal efficiency band | SEDBUK | A |
| NOx | Class | 5 |
| Electrical | | |
| Electrical supply | Volts/Hz | 230 / 50 |
| Power consumption | Watts | 150 |
| External fuse rating | Amps | 3 |
| Ingress protection rating (as supplied) | | IPX5D |
| Pump overrun | | Yes |
| 24hr pump exercise | | Yes |
| Integral frost thermostat (boiler protection only) | | Yes |
| Weight | | |
| Installation lift weight | kg | 47.5 |
| Mechanical & Hydraulic | | |
| DHW system pressure (maximum) | bar | 8 |
| DHW operating pressure (minimum) | bar | 0.15 |
| Safety pressure discharge | bar | 3 |
| Integral automatic bypass | | Yes |
| CH system capacity (maximum) | litres | 125 |
| Gas supply pipe size | mm | 22 |
| Flow & return pipe size (CH) | mm | 22 |
| Flow & return pipe size (DHW) | mm | 15 |
| Temporary filling loop | | Optional |
| Compartment ventilation required | | No |
| Pre-plumb jig | | Yes |
| Flue systems | | |
| Standard concentric flue diameter | mm | 60/100 |
| Standard flue length | mm | 1000 |
| Maximum equivalent length horizontal | m | 10 |
| Maximum equivalent length vertical | m | 10 |
| Optional twin pipe vertical flue diameter | mm | 80/80 |
| Maximum equivalent length horizontal | m | 20 |
| Maximum equivalent length vertical | m | 20 |
