Professional diagnosis for furnaces with no heat, cycling, airflow, thermostat/control or unusual operating problems.
Langley service area: We diagnose and repair furnaces throughout Langley Township and Langley City — including Willoughby, Walnut Grove, Murrayville, Brookswood and Fort Langley. Langley's range of newer townhomes, established detached homes and larger rural properties means furnace configurations vary: compact installations in Willoughby, extended duct systems in Brookswood, older equipment on larger Fort Langley properties. We work across makes and models.
What We Diagnose
These are the conditions we most commonly respond to at Langley service calls. Symptoms can share causes — proper diagnosis establishes the repair path before any work is done.
The furnace runs — the blower operates — but delivers no warm air, or produces heat only some of the time. Common causes include igniter failure, a faulty gas valve, a tripped limit switch, or a pressure switch fault on high-efficiency models. The unit may show a fault code that guides the diagnostic. Do not attempt to bypass safety controls or re-light a furnace repeatedly if it fails to ignite.
The furnace starts, runs briefly and shuts off before the call is satisfied — then restarts shortly after. This short-cycling pattern is most often caused by the unit overheating and tripping its high-limit switch due to restricted airflow (clogged filter, blocked return) or a failing blower motor. It can also indicate an oversized unit for the home's heat load. Either way, it stresses the heat exchanger over time.
Low register output, reduced airflow throughout the home, or noticeably different temperatures between rooms or levels. Often linked to a clogged filter, a deteriorating blower wheel, a failing blower motor or duct restrictions. In Langley's multi-level newer homes, imbalanced duct distribution can concentrate airflow on one floor while another under-heats — this is a duct issue, not always a furnace fault.
The furnace does not respond to heat calls, runs continuously regardless of setpoint, or shows error codes or fault indicators on the control board display. Wiring faults, failed control boards, low-voltage issues or thermostat calibration drift can all produce these symptoms. Diagnosis distinguishes between a thermostat fault and a furnace control fault before repair is recommended.
Banging on startup (often delayed ignition), rattling or vibration during operation, squealing from the blower (worn bearings), or grinding sounds that indicate a more serious mechanical issue. A furnace displaying a persistent fault code or locking out should be diagnosed — repeatedly resetting a safety lockout without identifying the cause can mask an underlying problem.
High-efficiency furnaces have multiple safety controls — high-limit, pressure switches, flame sensors, draft inducer proving switches — that shut the unit down when they detect an out-of-range condition. A furnace that enters repeated safety shutdowns is telling you something. The right response is diagnosis, not resetting the unit and hoping the problem clears.
Gas safety: If you smell gas near the furnace, do not attempt to operate it or any electrical switches. Leave the building and call your gas utility's emergency line from outside. Do not attempt to adjust gas connections, combustion settings, or bypass safety controls on a gas appliance — these require a licensed gas technician under permit.
Decision Guide
Most furnace faults are repairable. The replacement conversation makes sense when repair cost, equipment age and the home's future HVAC plans align in that direction — not automatically.
If diagnosis points toward replacement, we can discuss the options — new furnace, heat pump or a combined system — suited to your home's configuration and Langley conditions. See our Furnace Installation Langley page or furnace replacement guidance for what that process involves.
How It Works
A repair starts with finding the actual cause — not a parts swap based on the symptom alone.
We check the furnace make, model, age and configuration, retrieve any stored fault codes from the control board, and discuss what you've observed — when the problem started, how often it occurs, and any recent changes to the system or filter maintenance.
We test the control board, thermostat signal, igniter, flame sensor, gas valve and safety switch circuits. Many furnace faults that look like a gas or mechanical problem trace to an electrical component — systematic checks prevent unnecessary parts replacement.
We check filter condition, blower motor operation, blower wheel condition and static pressure where relevant. A furnace that cycles on high-limit is almost always an airflow problem first — confirming this avoids replacing controls when the real fix is the air path.
On older equipment or units that have been short-cycling repeatedly, we inspect the heat exchanger for visible cracks, separation or signs of combustion gas migration. A cracked heat exchanger is a safety concern and affects the repair-vs-replace conversation.
Once the fault is identified, we complete the repair, restart the system, verify ignition sequence, heat delivery and safety control operation, and confirm the furnace is running correctly before leaving.
FAQ
Contact us to discuss the symptoms and schedule a diagnostic service call.
Request Service