A boiler that won't fire despite everything else looking fine often comes down to a small switch confirming the exhaust is venting properly.
Tell us what you need—we’ll call you back fast.
Quick answer
Replacing a boiler's pressure switch in Delta generally falls in the $250 to $1,800 boiler repair range, with most jobs closer to $400 to $900, plus a $90 to $150 diagnostic call. That's a 2026 public-market ballpark for the region, not a quote — CANRO's certified gas technicians confirm your actual price after inspecting the venting and switch.
Need a licensed gas fitter for your hot water / boiler? Call CANRO at (604) 359-1081 — residential natural-gas heating and hot water across Metro Vancouver since 1999.
On induced-draft and forced-draft boilers, a pressure switch confirms that the combustion blower is actually creating enough draft to safely exhaust combustion gases before the control system allows the gas valve to open. It's a safety interlock, similar in purpose to a flow switch or low water cutoff, just focused on the venting side of the appliance rather than the water side.
When this switch fails or reads incorrectly, the boiler typically refuses to fire at all, locking out with a venting-related fault rather than attempting ignition with unproven draft. Causes range from a genuinely failed switch to a blocked or restricted vent pipe that's legitimately preventing adequate draft — which is why diagnosing this properly means checking the venting itself, not just swapping the switch.
A meaningful share of Ladner's older homes vent gas boilers through masonry chimneys shared historically with a fireplace, and over years those older venting paths can develop restrictions from debris, nesting material, or general deterioration that a pressure switch will correctly flag as inadequate draft — meaning the fix is really about the venting, not the switch. Coastal salt air near Boundary Bay can also accelerate corrosion on metal vent components over time, which sometimes contributes to the same kind of restriction.
Newer condensing boilers across East Delta typically vent through PVC or similar plastic piping rather than a masonry chimney, and pressure switch faults on those systems more often trace back to a genuinely worn switch or a minor vent pipe sag than to the kind of restriction we see in older chimney-vented systems.
| Item | Typical range | Notes |
|---|---|---|
| Diagnostic / service call | $90 – $150 | Includes checking the venting itself, not just the switch |
| Licensed labour | $95 – $165 per hour | Includes draft testing after the repair |
| Pressure switch replacement | $250 – $1,800 (most $400 – $900) | General boiler repair range applies |
A confirmed switch failure with clean, unrestricted venting is a moderate, contained repair. If the underlying issue is actually a restricted or damaged vent, that additional work sits outside this specific part's cost and gets discussed separately once found.
Because a pressure switch is a proxy for whether combustion gases are venting safely, we never treat a suspected fault here as a simple part swap without also confirming the venting itself is clear and properly configured. That extra step is standard practice, and it's part of why this repair sometimes takes a bit longer on site than the part cost alone would suggest.
Safety note
If you ever smell gas, hear hissing near a fitting, or a carbon monoxide alarm sounds, leave the house first and call FortisBC's emergency line at 1-800-663-9911 from outside before doing anything else. Only a Technical Safety BC licensed gas fitter should open a sealed combustion chamber, gas valve, or venting run.
A pressure switch fault holds the gas valve closed until adequate draft is confirmed, so the boiler can look otherwise healthy while still refusing to ignite because of a venting-side issue.
Yes, and checking the venting itself is part of any proper diagnosis here — a switch replacement won't fix an underlying vent restriction.
It's worth addressing promptly since there's no heat until it's resolved, though the pressure switch failing to allow ignition is the safety system working as intended rather than a hazard itself.
Older masonry chimney venting can develop restrictions over years that trigger this switch, so yes, we see it somewhat more often on that type of venting than on newer PVC-vented systems.
Yes, checking that the venting path is clear and functioning is a standard part of diagnosing any pressure switch fault, not a separate add-on.
It depends on whether the venting itself needs attention alongside the switch; a straightforward switch replacement with clean venting is a moderate, same-visit repair.
Family-run, TSBC-licensed (gas LGA0043870 · boiler LBP0046450), serving Metro Vancouver homes since 1999. Residential, natural gas only.
Call (604) 359-1081 Email info@canroheat.ca“Canro does an amazing job! Super professional and skilled with everything—boilers, furnaces, and AC. Always a pleasure working with them!”
“Five stars for Canro. We needed a replacement of a 30-year-old boiler. A new high-efficiency unit was installed—clean, professional work.”
“I can’t speak highly enough about George, who was recommended for a boiler service call for my parents’ home. George is excellent.”
25+ years keeping Metro Vancouver homes comfortable. Honest advice, upfront pricing, work that lasts.