How to Repressurize Your Boiler — A Vancouver Homeowner Guide
Published: July 14, 2026 — CANRO Heating & Cooling — Greater Vancouver, BC
What Should Your Boiler Pressure Be
A healthy boiler system should maintain between 1.0 and 1.5 bar when cold, and up to 2.0-2.5 bar when the system is hot and operating. If the pressure drops below 1.0 bar, the boiler may shut down or display a low-pressure error code. If pressure exceeds 2.5 bar, the pressure relief valve may discharge water as a safety measure. Check your pressure gauge regularly — it is usually located on the front panel of the boiler or on the pipework below.
When to Repressurize
Repressurize your boiler when the pressure gauge reads below 1.0 bar while the system is cold. Do not repressurize a hot system — wait for it to cool. If you need to repressurize more than once every 2-3 months, there is likely a leak that needs professional investigation.
How to Use the Filling Loop
Locate the filling loop — a flexible braided metal hose with a valve at each end. Open one valve fully, then slowly open the second while watching the pressure gauge. Fill until the gauge reads 1.0-1.5 bar, then close both valves tightly. Do not overfill.
After Repressurizing
Bleed air from radiators starting with the lowest and working upward. Recheck the pressure after bleeding. Run the boiler and monitor the pressure as it heats up. If pressure rises rapidly above 2.5 bar, the expansion tank may have failed and needs professional replacement.