The Navien NCB Series (particularly the current NCB-H models like NCB-240/110H or NCB-240/130H) is a high-efficiency condensing combi-boiler that provides both space heating (hydronic/radiant/baseboard) and endless on-demand domestic hot water (DHW) in one compact, wall-hung unit. It's popular in homes without space for separate boilers and tanks, offering up to 95% AFUE (Annual Fuel Utilization Efficiency), which means excellent energy savings on gas bills compared to older systems.

Key Defining Features

  • Condensing technology with dual stainless steel heat exchangers — Durable, corrosion-resistant design recovers extra heat from exhaust gases for maximum efficiency and longevity.

  • High DHW performance — Up to 199,900–210,000 BTU/h input for hot water, with flow rates up to ~5.4 GPM at a 70°F rise (enough for multiple showers + appliances simultaneously), and a DHW turndown ratio of 15:1 for precise control and less cycling.

  • Heating output — Varies by model (e.g., 60,000–130,000 BTU/h max input), with heating turndown up to 11:1 for consistent, efficient operation.

  • Advanced controls — Easy-to-use multi-line LCD display, intuitive navigation, built-in pump, flow adjustment valve, mixing valve, and 3-way valve in the DHW module.

  • Flexible venting — Supports 2" PVC up to 65 feet (economical Schedule 40), dual Venturi system for better combustion and easy natural gas to propane conversion.

  • Other highlights — Vent Installation Detector (VID) for safety, compatible with NaviLink Wi-Fi remote control/app, low NOx emissions, compact wall-hung design (about 17" W x 29" H x 13" D), ENERGY STAR certified in many configurations, and built-in safety features like low water cutoff compatibility.

Models range from smaller (e.g., NCB-190/060H for modest homes) to larger (e.g., NCB-240/130H for bigger demands).

Warranty

Per Navien's official residential terms (for properly installed units):

  • 10-year limited warranty on the heat exchanger(s).

  • 5-year limited warranty on parts.

  • 1-year limited warranty on labor.

Warranties require professional installation by a licensed contractor, compliance with the manual, and often registration. Full details, exclusions, and claims are on Navien's website (navieninc.com) or in the product manual—warranty can be voided by improper maintenance or unauthorized purchases (e.g., online resale).

Basic Homeowner Service and Maintenance Tips

Combi-boilers like the NCB need regular care to maintain efficiency, prevent scale buildup (especially in hard water areas like parts of Alberta), and ensure safe operation. Always refer to your owner's manual, and schedule annual professional servicing by a certified technician (highly recommended for gas appliances).

  • Clean inlet water filters/screens — Check and rinse the cold water inlet screen (DHW side) and any heating loop screens every 3–6 months (more often with sediment-prone water) to prevent flow restrictions.

  • Flush/descaling if needed — In hard water areas, descale the heat exchangers periodically (e.g., annually or per water quality test); use approved descaling solutions—DIY possible but risky (may void warranty if done wrong); pros use specialized kits.

  • Check condensate drain — Ensure the drain line isn't clogged; flush annually with a mild vinegar solution to avoid backups (condensing units produce acidic condensate).

  • Keep area clear — Maintain clearance around the unit for airflow/venting; no storage of flammables nearby.

  • Monitor system — Watch for error codes on the display, unusual noises, reduced hot water flow, or heating issues—address promptly. Test pressure relief valve occasionally.

  • Water quality — Verify boiler loop water quality; add inhibitors if needed (pro recommended). Bleed air from radiators/baseboards as required.

  • Annual professional tune-up — Essential: Includes checking gas pressure, cleaning burners/heat exchangers, verifying combustion, testing safeties, and inspecting venting/condensate system.

  • CO detectors — Install and test carbon monoxide detectors near the unit—critical for gas appliances.

Navien combi-boilers are reliable, efficient units made with Korean engineering, well-suited to Canadian winters (including Edmonton's cold climate). For exact model specs, installation, or parts, contact a local Navien-authorized dealer or visit navieninc.com