Navien NHB Boiler Installation: What the Job Involves

Need a licensed gas fitter for your gas boiler? Call CANRO at (604) 359-1081 — residential natural-gas heating and hot water across Metro Vancouver since 1999.

What a proper NHB installation is made of

The NHB is a condensing heat-only boiler. It heats water for a closed loop that serves radiators, baseboard or in-floor tubing, and if the home needs domestic hot water from the same boiler, it does so by heating a separate indirect tank. Installing one is less about hanging a box on a wall than about connecting a small system correctly: gas in, exhaust and intake pipes, a condensate drain, heating piping, an expansion arrangement, controls and power.

We install as a licensed gas contractor and are not an authorized or factory dealer. Every dimension, clearance and material we mention below is set by the manufacturer's installation manual and the gas code, and that manual governs the job.

Step one: the heat loss calculation

Sizing starts with arithmetic, not with the old boiler's nameplate. A room-by-room heat loss calculation uses the house's walls, windows, ceilings, air leakage and layout. It regularly shows that the old boiler was larger than the house needed, especially where windows were replaced or insulation was added. An oversized condensing boiler cycles constantly, and short cycling wastes gas and wears components.

The same visit looks at the emitters. Cast iron radiators, baseboard and radiant floors each want different water temperatures, and a condensing boiler earns its keep when it can run at the lower temperatures the emitters allow.

Step two: choosing the location and the vent route

A condensing boiler uses sealed plastic pipes for intake and exhaust, so it does not need a chimney, and many Lower Mainland installs move the boiler away from an old masonry flue altogether. The location is chosen with access for service, the length and direction of vent runs, clearance to windows and other openings at the termination, distance to the gas meter and a workable route for the condensate drain.

Vent material, sizing and support are set by the boiler's manual, and mixing materials that the manual does not approve is a shortcut we do not take. An old chimney that no longer serves any appliance is also dealt with, since an abandoned flue can collect moisture and cause its own problems.

Step three: condensate, gas and water connections

• Condensate: a trap and a drain line with continuous slope to a suitable drain, protected from freezing wherever it runs through cold space. Some installs include a neutralizer where the manual or local practice calls for one.
• Gas: a supply line sized for the load, with a shut-off, sediment trap and connection pressure-tested and leak-checked before the boiler is fired.
• Heating water: isolation valves, a properly sized expansion tank, an air separator and a fill arrangement suited to the system.
• Pump and zoning: circulators and zone valves matched to the loop, rather than left over from the old system.
• Safety devices: a relief valve piped to a safe discharge point, and controls that shut the boiler down if something goes wrong.

Each item is a place where a hurried job cuts corners. A relief valve piped to nowhere, a drain that runs uphill or a gas line squeezed to save time is how callbacks begin.

Step four: cleaning the loop before the new boiler joins it

Old systems carry sludge, air and sometimes leftover chemistry. A new boiler connected to a dirty loop can be damaged by exactly what the old one carried. We clean or flush the loop as the situation calls for, fill it with clean water and treatment appropriate to the system, and remove air thoroughly. Metro Vancouver's soft water is easy on a heating loop, but old cast iron and steel produce sludge regardless of the water source.

Typical Lower Mainland installation situations

The same boiler can be installed very differently in each of these, which is why a written quote after an assessment is worth more than a number given over the phone.

Common installation mistakes we correct on service calls

• A condensate line that runs uphill, sags or discharges somewhere it can freeze.
• Vent pipe of a material the manual does not approve, or unsupported runs that have sagged.
• A missing or mis-sized expansion tank, or one installed on the wrong side of the pump.
• No air separation, so the loop gurgles and the pump wears.
• An oversized boiler chosen because the old one was large.
• A dirty loop connected without cleaning.

None of these is exotic. They are the ordinary consequences of installing quickly rather than carefully, and each is avoidable.

Permits, inspection and who does the work

Gas work in BC must be done by a Technical Safety BC licensed gas fitter, and a gas permit is required for a boiler installation. CANRO holds gas licence LGA0043870 and boiler licence LBP0046450. Some jobs also involve the municipality, for example where venting or structural changes are made. We arrange what applies and the work is inspected before it is signed off.

Commissioning: the part homeowners rarely see

1. Purge and test the gas supply, then check every connection for leaks.
2. Fill, pressurise and check the loop for leaks, and bleed air until the system runs quietly.
3. Fire the boiler and measure combustion with an analyzer, adjusting only as the manual allows.
4. Test the safety shutdowns and the relief valve piping.
5. Set controls to suit the house and walk the owner through the thermostat, the gauge and what to watch.

The report from commissioning is worth keeping alongside the manufacturer's warranty paperwork. Warranty terms are set by the manufacturer, so verify your certificate.

Ballpark cost, and what moves it

As a general ballpark, boiler installation in Metro Vancouver runs about $6,500-$14,000+, ballpark, not a quote. Where a job lands depends on the boiler and controls chosen, whether a hot-water tank is added, how far the vent and condensate runs are, gas line work, the condition of the existing loop and how easy the mechanical space is to work in. The CANRO office confirms a firm figure in writing after a short assessment.

Programs from FortisBC, CleanBC and the federal government change from time to time, and the Canada Greener Homes Grant is closed. Confirm current eligibility with the program itself.

Frequently asked questions