Water pressure, PRV and thermal expansion

Understand how a pressure-reducing valve, check valve and water heater can create a closed system where pressure rises during heating.

VERT / GREEN

Measure static/dynamic pressure at different times before replacing fixtures or relief devices.

JAUNE / YELLOW

In a closed system, thermal expansion needs an appropriate accommodation method; the symptom is not always a bad water heater.

ROUGE / RED

Relief valve discharge, excessive pressure, corroded expansion tank or PRV work: professional.

Guided triage

Pressure rises after heatingCheck whether the system is closed and thermal expansion is managed.T&P valve dischargesNever cap the relief valve; diagnose pressure/temperature/expansion.PRV or check valve presentDocument setting and expansion protection before changes.Stable pressure documentedKeep baseline readings in My Home.

Tools / data

Water pressure gauge
PRV/check-valve inventory
Water-heater data

What the professional checks

Confirm open/closed system
Size expansion protection
Verify relief valves/pressure

Official sources

CNRC — expansion thermique plomberie

Source check / vérification: 2026-08-22. Triage et planification seulement; les travaux réglementés restent aux professionnels requis.

Related path

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