Assess First. Recommend Second.
An ON combi platform with flow-adjustment and mixing technology for changing hot-water demand.
Subject to registration, correct commissioning and recorded annual servicing.
Your written quotation confirms the cover included. Register within one month of installation.
The model-specific UK page advertises 10 years of parts and labour cover. The installation manual requires registration within one month, correct installation and commissioning, a completed Benchmark checklist and servicing at least annually by a competent Gas Safe registered engineer, with records retained. System-water treatment and any required protection components must meet the selected manual. Maximum cover is not automatic; the written quotation confirms actual cover. No manufacturer accreditation or paid extension entitlement is assumed. Any proposed extension, qualifying components or installer eligibility must be verified before agreement. Component-only cover must not be presented as whole-boiler cover.
Official model warranty information · Check registered warranty · Installation and servicing requirementsAn ON combi platform with flow-adjustment and mixing technology for changing hot-water demand.
Natural-gas specification table: heating at 80/60°C; condensing heating at 50/30°C. LPG conversion is supported but no LPG performance figure is inferred.
| Model / configuration | Heating at 80/60°C | Heating at 50/30°C | Hot-water output | Hot-water delivery |
|---|---|---|---|---|
| NCB500-1S+/30K | 4.2–24 kW | 25.8 kW | 30 kW | 12.3 l/min at 35°C rise |
| NCB500-1S+/32K | 4.5–26 kW | 28.2 kW | 32 kW | 13.1 l/min at 35°C rise |
| NCB500-2S/37K | 4.5–26 kW | 28.2 kW | 37 kW | 15.2 l/min at 35°C rise |
| NCB500-2S+/41K | 4.5–26 kW | 28.2 kW | 41 kW | 16.8 l/min at 35°C rise |
Navien documents natural-gas/LPG conversion for these configurations using the supplied kit. A Gas Safe engineer qualified for LPG must verify the correct kit, gas supply and manual, then convert, label and commission the appliance. The displayed output, flow and efficiency figures are natural-gas data, not verified LPG performance.
Model designations are verified; a separate merchant SKU or retail order code has not been verified and must be confirmed before ordering.
The product-page table calls the 41 variant NCB500-2S/41K. The installation manual uses NCB500-2S+/41K, retained here as the technical designation; confirm the supplied label before ordering.
| Configuration | Weight | Published modulation | Energy rating |
|---|---|---|---|
| NCB500-1S+/30K | 31 kg | 6:1 — manufacturer table | ErP A (93%) |
| NCB500-1S+/32K | 34 kg | 6:1 — manufacturer table | ErP A (93%) |
| NCB500-2S/37K | 34 kg | 6:1 — manufacturer table | ErP A (93%) |
| NCB500-2S+/41K | 34 kg | 6:1 — manufacturer table | ErP A (93%) |
A+ is a conditional package rating with the specified Navien Smart Plus controls, not the appliance alone. Lift weight and shipping weight can differ.
Outlet descriptions are manufacturer guidance, subject to sufficient measured water flow and dynamic pressure, outlet temperatures and pipework. Bathroom count alone does not establish delivery or suitability.
The digital display provides operation and energy-use information. Navien documents flow-adjustment and automatic mixing valves; incoming water performance still limits delivery.
The ON functions and 30–41 hot-water choices should be compared with your routines. This family is a different platform from the NCB500 cylinder-based system boiler.
The model-specific UK page advertises 10 years of parts and labour cover. The installation manual requires registration within one month, correct installation and commissioning, a completed Benchmark checklist and servicing at least annually by a competent Gas Safe registered engineer, with records retained. System-water treatment and any required protection components must meet the selected manual. Maximum cover is not automatic; the written quotation confirms actual cover. No manufacturer accreditation or paid extension entitlement is assumed. Any proposed extension, qualifying components or installer eligibility must be verified before agreement. Component-only cover must not be presented as whole-boiler cover.
Official model warranty statement · Registered warranty lookupSmart Plus control-pack compatibility and three-zone readiness are documented. Confirm the exact controller, wiring and accessories; a basic thermostat does not provide every connected function.
Casing: 680 × 395 × 285 mm (H × W × D). Pipework, flue and installation/service clearances are additional.
The Finder can shortlist individual configurations from your fuel and design answers. LPG conversion compatibility is recorded, but LPG-specific performance and supply must be confirmed at survey. Final output is subject to heat-loss, water and installation assessment.
Combi guidanceThe ON functions and 30–41 hot-water choices should be compared with your routines. This family is a different platform from the NCB500 cylinder-based system boiler.
The model-specific UK page advertises 10 years of parts and labour cover. The installation manual requires registration within one month, correct installation and commissioning, a completed Benchmark checklist and servicing at least annually by a competent Gas Safe registered engineer, with records retained. System-water treatment and any required protection components must meet the selected manual. Maximum cover is not automatic; the written quotation confirms actual cover. No manufacturer accreditation or paid extension entitlement is assumed. Any proposed extension, qualifying components or installer eligibility must be verified before agreement. Component-only cover must not be presented as whole-boiler cover.
Navien lists natural-gas and LPG support with an included conversion kit. Conversion, gas supply and commissioning must be completed by a suitably qualified engineer. The natural-gas figures in this guide are not assumed LPG ratings.
The installed price for your selected boiler is confirmed after assessment. The quotation covers the appliance, controls, flue, system preparation and any required pipework. A conversion or relocation can have a different scope from a straightforward replacement.
New boiler installations from £1,790 inc. VAT apply to a qualifying standard, straightforward replacement: one bathroom, fewer than 10 radiators and a standard horizontal flue, subject to survey. Specification and warranty selection affect the final cost. This is a general starting offer and is not a price for every model in this catalogue.
Read the starting-package conditions0% options over 3, 6, 9 or 12 months through Humm Group Limited, subject to application, affordability, eligibility, approval and provider terms. Any applicable deposit, fees and repayment conditions are confirmed during your enquiry/application. Acceptance is not guaranteed.
Finance terms and chargesTwo free annual services and a Hive Mini are available on qualifying installations only. Every model is considered under the qualification rules; inclusion in this catalogue does not confirm eligibility. Ask us to confirm the offer in your quotation.
Ask about Care+ eligibilityPlan the maintenance your appliance requires and keep its service records. If you are considering replacement because of a fault, diagnosis can help establish whether repair is a suitable option first.
Boiler servicing · Repair adviceProduct photography and technical information: Navien UK. Checked 2 October 2026. Family casing views may be shared across outputs; current stock and the precise supplied model are confirmed before quotation.
Price confirmed following assessment for this configuration. The general New boiler installations from £1,790 inc. VAT offer does not apply to every model or property.
From or indicative prices remain provisional. SwiftHeat issues a written fixed quotation for the agreed scope after the appropriate property and installation assessment, technical checks and warranty-package verification. Remote information gathering may be suitable initially; a home survey is required where the necessary checks cannot be completed remotely.
We assess heat loss, heating and hot-water requirements, water supply, controls and installation access before recommending an appliance. Bedroom count or a catalogue model number alone cannot establish the right boiler.
Gas Safe registration 978273 · Serving Cardiff, South Wales and across the UK.
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