Navien NCB300 28kW Gas Combi Boiler
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Navien NCB300 28kW Gas Combi Boiler
(Approx. 3-5 working days)


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The Navien NCB300-28kW is a compact, wall-mounted condensing gas combi boiler designed for smaller homes requiring efficient heating and hot water. It provides central heating and instantaneous domestic hot water without a separate cylinder.
This model delivers a domestic hot water output of 28kW with a flow rate of up to 11.5 litres per minute at 35°C rise. It features stainless steel heat exchangers for durability, a 6:1 turndown ratio for efficient modulation, and an ErP A-rated efficiency of up to 94%. The boiler is hydrogen-ready for a 20% blend.
Compact dimensions (680 × 395 × 283 mm) allow easy cupboard installation. It meets NOx Class 6 standards and supports smart controls via OpenTherm and Navien’s own systems.
- 28kW domestic hot water output for small homes
- Flow rate up to 11.5 l/min at 35°C rise
- Stainless steel heat exchangers for long-term efficiency
- Compact size: 680 × 395 × 283 mm
- Compatible with natural gas and LPG
| Brand | Navien |
|---|---|
| Width | 395 mm |
| Depth | 285 mm |
| Flow Rate | 16 l/h |
| Flue Included | No |
| Fuel Type | Gas |
| Heating Energy Rating | A |
| Heating Type | Condensing |
| Height | 680 mm |
| Max Heat Input | 24.7 kW |
| Central Heating Output | 24 kW |
| Min Heat Input | 4.3 |
| Min Heat Output | 4.2 |
| Model Name / No | NCB300-28C |
| Weight | 29 kg |
| Suitable For | Smaller Homes with 1 Shower |
| Usage | Internal Use |
| Length Of Warranty | 5 Years |
| Water Energy Rating | A |
| Mount Type | Wall Mounted |
- Delivery cost will be calculated at checkout once delivery address has been confirmed
- Delivery lead times are an estimate only
- Delivery drivers will always prioritise safety over convenience when offloading materials
- Bagged products such as cement and plaster cannot be returned once opened
- Jumbo bags cannot be returned once delivered
- All other goods may be returned within 3 months with a proof of purchase provided
- Chargeable pallets may be returned for a full refund
- All online pricing is specific to Northern Ireland only. Pricing for our Isle of Man branch may vary.
The Navien NCB300-28kW is a compact, wall-mounted condensing gas combi boiler designed for smaller homes requiring efficient heating and hot water. It provides central heating and instantaneous domestic hot water without a separate cylinder.
This model delivers a domestic hot water output of 28kW with a flow rate of up to 11.5 litres per minute at 35°C rise. It features stainless steel heat exchangers for durability, a 6:1 turndown ratio for efficient modulation, and an ErP A-rated efficiency of up to 94%. The boiler is hydrogen-ready for a 20% blend.
Compact dimensions (680 × 395 × 283 mm) allow easy cupboard installation. It meets NOx Class 6 standards and supports smart controls via OpenTherm and Navien’s own systems.
- 28kW domestic hot water output for small homes
- Flow rate up to 11.5 l/min at 35°C rise
- Stainless steel heat exchangers for long-term efficiency
- Compact size: 680 × 395 × 283 mm
- Compatible with natural gas and LPG
| Brand | Navien |
|---|---|
| Width | 395 mm |
| Depth | 285 mm |
| Flow Rate | 16 l/h |
| Flue Included | No |
| Fuel Type | Gas |
| Heating Energy Rating | A |
| Heating Type | Condensing |
| Height | 680 mm |
| Max Heat Input | 24.7 kW |
| Central Heating Output | 24 kW |
| Min Heat Input | 4.3 |
| Min Heat Output | 4.2 |
| Model Name / No | NCB300-28C |
| Weight | 29 kg |
| Suitable For | Smaller Homes with 1 Shower |
| Usage | Internal Use |
| Length Of Warranty | 5 Years |
| Water Energy Rating | A |
| Mount Type | Wall Mounted |
- Delivery cost will be calculated at checkout once delivery address has been confirmed
- Delivery lead times are an estimate only
- Delivery drivers will always prioritise safety over convenience when offloading materials
- Bagged products such as cement and plaster cannot be returned once opened
- Jumbo bags cannot be returned once delivered
- All other goods may be returned within 3 months with a proof of purchase provided
- Chargeable pallets may be returned for a full refund
- All online pricing is specific to Northern Ireland only. Pricing for our Isle of Man branch may vary.


