Boiler Not Heating or Losing Pressure? What It Means and When It Can't Wait

The most obvious sign is no heat at all. Just as common is partial heat: one radiator stays cold while the rest are warm, a radiant floor feels lukewarm in one zone, or the house never quite reaches the thermostat setting. In townhouses with in-floor heating, a single cold bedroom is often the first clue.

Next, look at the pressure gauge on the front of the boiler or on the nearby piping. A needle that keeps drifting lower over days or weeks means water is leaving the sealed system somewhere. A needle climbing high while the boiler runs is a different problem and deserves a call.

Listen too. A rumbling or kettling sound, like water boiling in a pot, often points to scale or restricted flow through the heat exchanger. Gurgling usually means air in the pipes. Finally, many modern units show an error code or lock out and ask for a reset. Photograph the code before doing anything else.

Confirm the thermostat is set to heat, the setpoint is above room temperature, and the batteries are not dead. Check that the boiler has power: look for a display or indicator light, and check the breaker panel and any service switch near the unit.

Read the pressure gauge with the system cold. As general guidance, many residential hydronic systems sit somewhere around 12 to 15 psi (roughly 1 to 1.5 bar) when cold, but your boiler label or manual is the real reference. If the reading is well below that, note it. Do not open fill valves or relief valves to adjust it unless the manual clearly says this is a homeowner task and you are comfortable doing it.

If one radiator is warm at the bottom and cold at the top, trapped air is the likely cause. Bleeding it is usually a reasonable homeowner job: turn the heating off and let things cool, hold a rag under the bleed valve, open it a quarter turn with a radiator key, and close it once water replaces the hissing air. Then recheck the gauge.

If your boiler shows an error and the manual allows a reset, one reset is fine. If the same code comes back, stop resetting. Repeated resets can hide a fault that is getting worse.

Some situations are not a next-week problem. If you smell gas, leave the house right away, do not flip switches or use anything that could spark, and call the FortisBC 24-hour emergency line at 1-800-663-9911 from outside. In BC, gas work is regulated by Technical Safety BC and must be done by a licensed gas fitter.

Treat these as same-day calls: water leaking from the boiler or piping, water discharging from the pressure relief valve, pressure climbing well above normal while the unit runs, scorch marks or soot around the burner area, or a carbon monoxide alarm going off. If a CO alarm sounds, get everyone outside first and call for help from there.

No heat during a cold snap also moves up the list. Metro Vancouver does not freeze often, but when temperatures drop below zero for a few days, pipes in crawl spaces and exterior walls become vulnerable, especially in older homes.

A good technician does not just reset the unit and leave. Expect them to ask what you noticed and when, then check the error history, system pressure, the expansion tank, the circulator pump, zone valves and the controls. On gas units, they should check ignition, burner condition, venting and combustion safety.

If pressure is dropping, the job is to find where the water is going. Common culprits include a leaking fitting, a worn pump seal, a relief valve that weeps, a failed expansion tank, or a leak hidden in a wall or slab. Topping the system up without finding the leak just buys a little time.

Age is a starting point, not a verdict. Many residential boilers last somewhere in the range of 15 to 25 years, but water quality, maintenance history and how hard the system works all shift that number.

Repair usually makes sense when the boiler is mid-life, the fault is a single part such as a pump, sensor or valve, and the heat exchanger is sound. Replacement starts to make sense when the heat exchanger is cracked or leaking, breakdowns keep repeating, parts are hard to find, or the repair cost is a large share of a new unit. Facing a big repair on an aging boiler? Ask for both options in writing and compare.

The cheapest boiler repair is the one you never need. A yearly service in early fall, before the rainy season settles in, lets a technician catch worn parts, low pressure and combustion problems while the weather is still mild and scheduling is easy.

Between services, a few habits help. Glance at the pressure gauge once a month during the heating season and note any change. Bleed radiators that develop cold tops. Keep the area around the boiler clear and test your CO alarms.

If something looks off, Encano Plumbing and Drain can take a look. We are a family-owned team based in Richmond, and you can call or text (604) 764-2031 any hour for a free estimate, with one flat price in writing before work starts. We also speak Portuguese and Spanish.