A furnace start is a chain of proofs. The thermostat calls. The inducer motor runs and a pressure switch proves the vent is clear. The igniter heats or sparks. The gas valve opens. The flame sensor proves flame within seconds or the valve closes. The blower waits for warm air, then delivers it. Clicking without heat is one link failed, and the technician's job is finding which link, in order, with a meter.
A Westminster no heat call begins by identifying what is actually heating the house: a conventional furnace, a wall heater, or a floor furnace from the original build. The start sequence applies to the furnace. For the wall and floor units, the honest visit is shorter: safeties and venting checked, parts availability stated plainly, and a replacement conversation if the unit has outlived its parts supply. What no heating visit here should skip is the heat exchanger and CO safety read, on any unit, at any age.
The common failed links, roughly by frequency: a flame sensor filmed over with oxide (cleaning or a modest part), a cracked hot surface igniter, a failing inducer, a clogged condensate trap on high efficiency units that mimics bigger faults, and control boards at the expensive end. Filters starve airflow and cause the overheating shutdowns that look like random failures.
The safety lines outrank the sequence. Gas or rotten egg smell: leave, then the utility or 911. A carbon monoxide alarm sounding: the same. A cracked heat exchanger is the finding that ends a furnace's life for safety reasons, and any technician who finds one will shut the system down and show you the evidence. That is not a sales tactic; it is the rule the trade works under.
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