Free checklist
Electric duct heater annual maintenance checklist
The annual electric duct heater service is the deep pass: the measurements, cleanings and tests a quarterly round doesn't reach. This checklist keeps the full service on record with the photos that make it defensible later. Work is commonly verified against NEC (NFPA 70), IMC (mechanical code), manufacturer's published instructions. Confirm the edition your authority having jurisdiction has adopted.
The checklist
Every item, and the photo evidence it needs
The photo count on each row is what RTI would require before the item can be submitted. Work the list here and watch the gate hold, or load it into RTI and let it enforce the real thing.
Isolation and nameplate
Heater, fan and control sources locked for the annual
Heater disconnect, fan starter and control power locked and tagged, box proven dead; interlock and limit tests run under the temporary release (covers on, clear, locks off by owner), then re-locked.
Nameplate kW and voltage matched to the circuit feeding it
Nameplate kW, voltage, phase and amps compared with the breaker or the fuse ratings read once the box is proven dead, the disconnect and the panel schedule, any mismatch reported to the owner.
Element and contactor service
Elements cleaned, checked and resistance verified stage by stage
Coils cleaned of dust and lint, no cracked or grounded elements, each stage's resistance and draw checked against the nameplate and logged.
Contactors and terminations serviced
Contactor contacts clean and not pitted, no sign of welding, power and control terminations torque-verified or resistance-measured, re-torqued only where found loose, no heat discoloration.
Element insulation resistance to ground measured
Insulation tester reading from each stage to the frame logged against last year's value and the manufacturer's minimum, a falling reading flagged before it trips.
Heater's internal stage fuses inspected where fitted
Fuse ratings match the heater's wiring diagram, clips tight and holders free of heat discoloration, on heaters built with their own stage fusing.
No photoSCR heat sink and cooling fan cleaned where fitted
On SCR-controlled heaters, heat sink fins cleared of dust and any cooling fan turning freely, so the controller does not overheat and fold back.
No photo
Interlock verification
Proving switch sensing parts inspected
Pressure pickups and tubing clear and uncracked, or the sail paddle straight and free on its pivot, so the switch responds to real airflow.
Proving switch set point checked against the heater's minimum
Duct pressure or velocity read with a manometer beside the switch, set point compared with the manufacturer's minimum airflow for the heater and left at the manufacturer's setting.
Airflow interlock function-tested by interrupting airflow
With a stage calling, airflow actually interrupted and the heater confirmed dropping out at once; documented by the licensed tech, acceptance by the owner or AHJ, interlock left as designed.
Cutout verification
Limit sensors seated and matched to the parts list
Limit discs or bulbs seated in their mounts across the elements, capillaries unkinked, and each limit's rating matching the manufacturer's replacement parts list.
High-limit cutouts function-tested and reset
Automatic and manual limits confirmed opening the heater under test and the manual limit needing a physical reset; documented by the licensed tech, acceptance by the owner or AHJ, never bypassed.
Return to service
Covers fastened and every lock removed by the person who hung it
Element and terminal box covers back on, tools and rags out of the duct, and each lock and tag removed by whoever applied it under the site's procedure.
Heater run through a full heat call and back to automatic
Fan started first, the call raised to full and dropped, every stage and the controller following it and discharge temperature rising, then the heater left in automatic.
Annual readings logged beside last year's values
Insulation resistance, set points, nameplate check and repairs logged under the heater's tag beside last year's values, deficiencies raised to the owner.
No photo
What usually sends this back
The failures are almost always the evidence, not the work
- Airflow proving and high-limits function-tested by talking, not by actually interrupting airflow and confirming the heater drops out.
- Contactor contacts pitted from stage cycling and never checked, so a stuck contactor holds an element on with no call.
Verified against
Common questions
6 answers
- What does this electric duct heater annual checklist cover?
- 15 items across 5 sections, covering isolation and nameplate, element and contactor service, interlock verification, cutout verification, and more. Each item spells out what the person walking the job is actually looking for, not just a box to tick.
- Who should run this inspection?
- The HVAC service lead with the licensed tech who tests and documents the safeties; the field observes and documents the results.
- When in the schedule should this walk happen?
- Once a year ahead of the heating season, coordinated with the air handler service so the duct can be opened.
- Why do these items ask for a photo?
- 12 of the 15 items call for photo evidence, 15 photos in all. A checklist answer without the photo is a claim; the photo is what makes the record worth something in a dispute and lets a reviewer approve work without re-walking the job.
- What most often fails an electric duct heater annual inspection?
- Airflow proving and high-limits function-tested by talking, not by actually interrupting airflow and confirming the heater drops out. Contactor contacts pitted from stage cycling and never checked, so a stuck contactor holds an element on with no call.
- Can I use this checklist in RTI?
- Yes. Start a free RTI workspace, build this list as a checklist, and the Photo Gate holds the submit button until every mandatory item is answered and its photos are attached. Approved inspections roll into a branded turnover package with a tamper evident audit trail.
Run it with the Photo Gate
A checklist nobody can submit half-finished
Load this list into RTI, stick a QR tag on the area it covers, and the submit button stays locked until every mandatory item is answered and the 15 required photos exist. Approved walks roll into a branded turnover package with a tamper evident record behind every line.
See all 508 checklists · 6741 items and 5984 photo requirements in total.