Gas boiler will not fire, keeps locking out, or heats intermittently in West Chester? PECO gas heats the overwhelming majority of the area — standing-pilot atmospheric units in the oldest downtown rowhomes alongside sealed and condensing units in the retrofitted homes and townships. Ignition, flame sensing, and condensate faults are the everyday calls. Call to describe the symptoms.
General inquiries: 7 AM–7 PM · Emergency calls: 24/7 · (888) 766-1474
Local details that change the triage.
Downtown and the surrounding townships are served by PECO for natural gas — if you smell gas, their emergency line (or 911) comes before any boiler call, from outside the building. Gas coverage is broad here; the unpiped pockets are the exception — township-edge streets and a few of the oldest downtown blocks — where homes run oil or propane, worth confirming before you describe the system on the call.
The gas stock spans generations: standing-pilot atmospheric boilers in the oldest downtown rowhomes — thermocouples, pilot assemblies, spill switches — and sealed and condensing units in the retrofitted homes, rental conversions, and township houses, where the fault map is igniters, flame sensor rods, and condensate drains. Saying which generation you have, or just describing what you see, routes the triage correctly.
What the local mix produces.
On the older atmospheric units, the pattern is pilot and safety-control wear: thermocouples that stop proving flame, pilot orifices that clog with dust and lint, spill switches that trip on aging venting, and gas valves that get sticky with age. These parts are consumable — a thermocouple every few years on a decades-old downtown boiler is normal maintenance, not a failing system.
On the sealed and condensing units, the pattern is ignition-component wear plus winter condensate faults: hot-surface igniters that crack, flame sensor rods that coat with oxide, and externally-run condensate drains that freeze on teen-degree January nights — the classic dead-by-morning-after-gurgling call. In the rental conversions, an added wrinkle: deferred maintenance accelerates every one of these faults, so a lockout in a rental often has two causes, not one. What matters is diagnosing which component failed rather than replacing parts by guess.
The fingerprints, with local context.
For the full technical breakdown of gas boiler systems, see our national gas boiler repair guide.
Symptoms that narrow the diagnosis.
Most gas no-heat calls are ignition faults, and the pattern tells the story. Fires for seconds, then cuts out points at the flame sensor: the burner lit, but the control cannot prove flame, so it shuts down on safety. Fan runs, no flame, lockout points at the igniter or gas valve — the sequence never got past step one. Pilot lights but will not stay lit on an old atmospheric unit points at the thermocouple. Bang or boom on startup is delayed ignition: stop resetting and call, because unburned gas detonating is not a nuisance, it is a hazard.
One safety note that matters: a carbon monoxide alarm sounding near the boiler is never a boiler-repair call — leave the building and call 911. CO is odorless, and a cracked heat exchanger or blocked flue is a get-out-first situation.
Straight answers before you call.
The PECO-gas era spans generations: standing-pilot atmospheric units in the oldest downtown homes, sealed units from the retrofit waves, and condensing units in the newest work. Each generation fails in its own dialect — pilot and draft, then sensors and pressure, then condensate and electronics. The tech's first job is placing your unit in its generation.
Wear on the ignition train: thermocouples and pilot assemblies on standing-pilot units, flame sensors and ignitors on electronic-ignition ones. Decades of heat cycling end every ignition part eventually. Downtown's atmospheric units are old enough that ignition parts are maintenance items — replaced on schedule, not in crisis.
They are often the silent partner in gas faults — old, oversized for modern exhaust, and deteriorating from condensation. Symptoms masquerade as boiler problems: lockouts on windy days, soot at the draft hood, lazy draft. A liner sized to the current boiler is the standard fix. If your chimney predates your boiler by decades, inspect it.
The expansion tank is the usual cause — its diaphragm fails, the relief valve dumps each cycle, and the auto-fill quietly replaces the water. Slow leaks at valves and joints are the runner-up. Watch the gauge cold: 12 to 15 psi and steady is healthy; a slow slide is a diagnosis, not a quirk. Do not just keep topping up.
The failure sequence: does it try to fire, how many attempts, what the lights do, any new sounds or smells — all without removing covers. Do not touch the gas train or open the cabinet; observation is your contribution, the inside belongs to the tech. A precise account of what the boiler does before it quits is genuinely diagnostic.
Related services in the West Chester area.
Call (888) 766-1474 — describe the fault code and symptoms for fast triage.
