When a Goodman electric heater fills a Keystone home with a burning smell, the culprit is usually one small part doing a big job: the sequencer. It is the component that switches your heat strips on and off in stages, and when it starts to fail, the symptoms it produces — the smell, the uneven heat, the tripped breaker — all trace back to it. This page is a deep dive into that one part: what it does, how it fails, how we prove it is the problem, and what the repair looks like.
What a Sequencer Actually Does
An electric heater does not turn on all at once. If every heat strip energized the instant the thermostat called for heat, the sudden current spike would hammer your electrical panel and the power grid alike. The sequencer prevents that. It is a staged switch, usually a small heat-activated relay, that brings the strip bank online one element at a time — first strip, pause, second strip, pause — and drops them out in reverse order when the thermostat is satisfied.
That staged rhythm is also what keeps the heat even. A healthy sequencer means each element runs for its full share of the heating call and rests when it should. When you understand that rhythm, the failure symptoms start to make sense: every burning smell from a failing sequencer is really the sound of that rhythm breaking down.
How a Failing Sequencer Smells
Sequencers fail in a few distinct ways, and each produces its own version of the burning smell:
- Contacts that stick on. The most common failure. A strip that should drop out stays energized, and the element keeps heating long past its turn. The smell is a persistent hot odor that lingers after the thermostat is satisfied, sometimes with rooms overshooting the set temperature.
- Contacts that chatter. Worn contacts can make and break rapidly instead of switching cleanly. The arcing produces an acrid, electrical smell — sharp and chemical, nothing like dust — and the rapid cycling wears the strip and the sequencer further with every heating call.
- Timing drift. A sequencer that stages too slowly leaves the first elements running overloaded while the rest of the bank never engages. The working strips run hotter than designed, bake dust onto themselves repeatedly, and produce a recurring hot smell on every cycle.
The one smell that is not the sequencer is the first-heat dust burn-off: a light, dusty odor that fades within 20 to 60 minutes of the season’s first heating cycle. Everything else — repeating smells, acrid smells, smells that linger after the system shuts off — belongs in the failure column.
Proving It: The Amp-Draw Test
A burning smell alone does not convict the sequencer; the proof comes from measurement. With the system running, a technician clamps an ammeter around each strip’s circuit and watches the staging sequence: every element should draw its rated current in order, hold steady, and drop out in order. A strip drawing nothing points to an open element or a dead stage. A strip drawing current when it should be off points to stuck contacts. Uneven draw across the bank points to timing drift or a dying element.
That test also rules out the other smell sources in one pass. The contactor gets checked for pitting and welding, the wire terminals get inspected for the discoloration that marks arcing, and the limit switches get verified. By the end, the smell has a name and a location — not a guess, a reading.
Safe Checks Before the Visit
A few safe observations help before your Keystone technician arrives, and they cost nothing:
- Note the smell’s character. Dusty and fading means burn-off. Acrid, plastic-like, or persistent means a failing part. Tell us which — it shapes what we bring.
- Check the filter. A clogged filter starves the strip bank of airflow and makes every element run hot, which can mimic sequencer symptoms. Replace it and see if the smell changes.
- Reset the breaker once, not repeatedly. A tripped breaker alongside the smell suggests the fault is drawing excess current. One reset to confirm; if it trips again, leave the heat off and call.
- Do not open the air handler. Electric heat runs on 240-volt circuits, and the sequencer and contactor sit behind panels that stay dangerous even with the thermostat off. Observation is safe; disassembly is not.
The Repair: What a Sequencer Replacement Involves
A confirmed sequencer failure is a contained, same-visit repair. The part is swapped, every wire in that circuit is inspected and re-terminated, and the full staging test runs again: each strip energizing and dropping out in order, amp draw even across the bank. Most sequencer replacements take one to two hours, depending on cabinet access and the condition of the wiring.
Sometimes the test reveals the sequencer was the victim, not the criminal — a welded contactor feeding it, or strip elements cracked from seasons of overheating. Then the scope grows honestly: contactor, strip bank section, or in the worst case the full bank. We show you the readings and lay out the options with the trade-offs in plain terms, so the decision is yours with the full picture. Genuine Goodman parts keep the staging behavior exactly as engineered, warranty-safe service protects the coverage you already have, and our vans carry the common sequencers and contactors so most of this resolves in a single trip with same-day dispatch across Keystone.
How do I know it is the sequencer and not the thermostat?
A thermostat problem usually shows up as wrong cycling — short cycles, no heat call at all, or the system ignoring the set temperature. A sequencer problem shows up as heat that behaves wrongly once it is running: persistent burning smell, rooms overshooting, strips staying hot after the call ends. The amp-draw test settles it definitively.
Can a bad sequencer damage the heat strips?
Yes. A stuck stage overheats its element far beyond design, which can crack or warp the element over time. That is why a repeating smell should not wait: the longer a bad sequencer runs, the more likely the repair grows from one part to the whole strip bank.
How long does a sequencer replacement take?
Usually one to two hours: the swap itself plus inspection of every connection in the circuit and a full staging test with amp-draw readings on each strip. Cabinet access and wiring condition set the exact time.
Will a new sequencer stop the breaker from tripping?
If the sequencer was the cause of the excess current draw, yes. If the breaker keeps tripping after the replacement, the fault is elsewhere in the circuit — a shorted element or damaged wiring — and the same visit’s testing finds it.
Why does the smell only happen sometimes?
Intermittent smells are classic failing-sequencer behavior: contacts that stick or arc only under certain loads or temperatures. It is also the stage most often dismissed. If it has happened more than once, have the bank tested before the intermittent failure becomes a permanent one.
Is sequencer replacement covered by my Goodman warranty?
That depends on the system’s age and whether it was registered. What we can promise is warranty-safe service: genuine Goodman parts and procedures that protect whatever coverage you have, rather than putting it at risk.