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Navien service

Navien: stop the relief valve weeping: expansion tanks for closed systems

Sizing, supply and installation of thermal expansion tanks on closed potable systems with backflow prevention or pressure-reducing valves, so the temperature-and-pressure relief valve stays seated instead of dripping through every heating cycle.

Gas storage tankElectric storage tankHeat-pump water heaterIndirect tank
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Quoted after assessment

Pricing for this service is confirmed in writing after CANRO assesses the equipment and property.

Where CANRO provides on-site service

On-site service is currently offered across Metro Vancouver: Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Delta, Langley, Port Moody, Port Coquitlam, Maple Ridge, Pitt Meadows, White Rock, Tsawwassen; plus Anmore, Belcarra, Lions Bay, Bowen Island, Abbotsford with travel or ferry arrangements confirmed by phone. Everything else on this site is reference information you can use anywhere in Canada.

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Expansion Control for Navien water heaters

When a backflow preventer or pressure-reducing valve closes the system, heated water cannot expand back to the main, so pressure climbs every time the tank fires and the relief valve becomes the release point. An expansion tank sized to the system volume and pressure absorbs the expanded water, which stops the drip cycle and protects the relief valve.

The service sizes the tank from the water-heater volume and the supply pressure, installs it on the cold side per code, sets the air charge, and verifies the system pressure, so the fix is engineered rather than guessed.

Working on a Navien unit? Have the model number from the rating plate and any code or flash pattern ready. Browse Navien series, models and fault codes to find yours; the details carry through when you request service.

What's included

  • Expansion tank sized to the system
  • Installation on the cold-water supply per code
  • Air-charge setting against supply pressure
  • Relief-valve behaviour check after install

Not included

  • Repairs to a relief valve damaged by years of discharge (quoted separately)

Process

How it works

  1. 01

    Check the system

    Backflow prevention, pressures and the drip pattern are checked.

  2. 02

    Size and install

    The tank is sized, installed and charged.

  3. 03

    Verify

    The relief valve is confirmed seated through a full heating cycle.

Why CANRO

4.9★

4.9 from 85+ Google reviews

As published by CANRO Heating & Cooling on canroheat.ca, checked September 7, 2026.

Technical Safety BC licensed gas contractor

Gas-fitting licence LGA0043870 and boiler licence LBP0046450, as published by CANRO.

Source: canroheat.ca

Serving Metro Vancouver since 1999

Founded by George in 1999, as stated on canroheat.ca. Boiler and hydronic expertise is CANRO's, not this domain's.

Source: canroheat.ca

Red Seal HVAC, WorkSafeBC and liability insured

As stated on canroheat.ca. Bonding and association memberships: not published.

Source: canroheat.ca

Frequently asked questions

Why does my relief valve drip when the tank heats?

Thermal expansion on a closed system raises pressure during heating and lifts the valve. An expansion tank absorbs the expanded water.

Do I need one?

Any system with a backflow preventer or pressure-reducing valve is closed and needs expansion control; the visit confirms it.

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On-site service in Metro Vancouver, BC. Call to check availability.

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Related services and help

Sources and verification

Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.

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