JL Heating & Air — Furnace Service & Clean Checklist

1. Arrival Speech

“Hi, I’m ______ with JL Heating & Air. Today we’re doing your furnace service and cleaning. Before I get started, is the furnace heating okay? Any noises, cold rooms, short cycling, smells, or anything else you want me to look at while I’m here?”

Park professionally and arrive clean/professional.

Greet client, confirm service, listen for concerns.

Confirm there is a working CO detector in the home. If none, recommend one.

Take arrival photos of furnace, venting, thermostat, filter, and work area.

2. Safety Before Touching Equipment

Gas + electricity + combustion. Never trust a switch. Verify power is actually off before opening electrical, and know where the gas shutoff is before you start.

Turn thermostat/system OFF.

Shut off furnace power switch / breaker.

Verify power is actually off with meter before opening electrical.

Locate gas shutoff valve and confirm it operates.

Smell/check for any gas leaks at the unit before starting. If you smell gas, stop and address it first.

Discharge blower capacitor before touching terminals.

Use safety glasses and gloves when needed.

3. Cleaning Order

Clean first. Diagnose after the cabinet and burner area are clean enough to inspect properly.

Brush loose dirt, dust, and rust scale first.

Vacuum burner compartment, cabinet bottom, blower compartment, and accessible debris.

Blow out / brush spaces the vacuum cannot reach.

Wipe down cabinet, panels, and accessible surfaces.

Leave equipment cleaner than when you arrived.

4. Burners & Ignition

Inspect burners for rust, scale, spider webs, and debris. Clean as needed.

Inspect/clean flame sensor (light scuff only — do not sand aggressively).

Inspect hot surface igniter (HSI) or spark/pilot assembly for cracks and carbon.

Check HSI resistance (if applicable) and igniter mounting.

Flame Sensor µA (running) HSI Resistance Ω

Weak flame-sensor microamps is a top cause of nuisance lockouts. Note the reading before and after cleaning.

5. Heat Exchanger Inspection

A cracked or failed heat exchanger can leak carbon monoxide into the home. If you find a crack, hole, or separation: shut the unit down, tell Josh immediately, and do not leave it running. This is a red-tag / safety call.

Visually inspect heat exchanger for cracks, rust-through, holes, and separations.

Use camera/mirror and light to inspect hidden surfaces.

Watch flames during blower startup — flames that change/roll when blower kicks on can indicate a crack.

Confirm CO reading in supply air is acceptable (see combustion section).

6. Gas & Combustion

Take a combustion analysis whenever possible. High CO is a safety issue, not just an efficiency number.

Inspect gas valve, pipe, and connections for leaks (bubble test / leak detector).

Check manifold gas pressure against nameplate (typical NG ~3.5" WC, LP ~10" WC — verify nameplate).

Check inlet/supply gas pressure.

Run combustion analyzer: CO, O2/CO2, flue temp, draft.

Confirm flames are blue, steady, and seated — not yellow, lifting, or rolling out.

Manifold Pressure ("WC) Inlet Pressure ("WC) CO (ppm) O2 / CO2 (%) Flue Temp Draft

Rule of thumb: rising CO, sooting, or flame rollout = stop and investigate before signing off.

7. Electrical & Controls

Check for loose, burnt, or discolored wires and bad connections.

Inspect control board, transformer, and low-voltage wiring.

Test limit switch, rollout switches, and flame rollout safeties.

Test pressure switch(es) and check hoses/ports for blockage.

Inspect inducer motor — bearings, amp draw, mounting.

Test blower capacitor (after power off + discharged).

Blower Cap Rating Measured

Rule: replace capacitor if outside ±5% of rating, swollen, leaking, or rusty.

8. Airflow & Blower

Check air filter size, condition, airflow direction, and restriction. Replace if needed.

Check blower wheel for dirt buildup, wobble, vibration, and set screw.

Check blower motor, wiring, mounts, and amp draw if needed.

Confirm return air is adequate and registers/vents are open.

9. Venting & Drainage

Inspect flue/vent pipe for corrosion, sagging, proper slope, and secure joints.

Confirm vent termination is clear and properly supported (no blockage, no back-drafting).

High-efficiency: check condensate trap, drain line, and neutralizer for clogs.

High-efficiency: inspect intake/exhaust PVC for cracks, sag, and screen blockage.

10. Reassemble Before Power On

All wires back on correct terminals.

All panels and doors installed (door switch seats).

All screws back in place.

No tools, rags, or loose parts left inside equipment.

Gas left on, ready for startup.

11. Startup & Sequence of Operations

Watch the whole sequence in order. If any step is out of order or missing, stop and diagnose.

Turn power back ON and call for heat at thermostat.

Inducer starts and pressure switch proves.

Igniter heats / spark fires.

Gas valve opens and burners light evenly.

Flame is sensed and stays lit (no flame loss / re-try).

Blower starts after fan-on delay.

If bad noise, short cycle, rollout, or lockout: shut down and fix before continuing.

12. Temperature Rise & Performance

Let furnace run and stabilize.

Measure return and supply temperature.

Confirm temperature rise is within the range stamped on the nameplate.

Return Temp Supply Temp Temp Rise

Rise too high = airflow problem (dirty filter/coil/blower). Rise too low = overfiring/airflow. Investigate if out of range.

13. Recommendations

Gather facts before making recommendations.

Explain what is good first.

Explain what needs attention.

Explain what should be repaired now — especially anything safety-related.

Issues / Recommendations

14. Upsells & Add-Ons

Tap anything the client is interested in. Just flag interest so Josh can follow up with pricing.

CO Detector(s) Every gas-heat home should have working CO alarms. Easy, high-value safety add.

Power Surge Protection Protects control board, inducer, and blower motor from spikes & brownouts.

Smart / Programmable Thermostat Schedule, remote control, energy savings; flag if current stat is basic / dying.

Whole-House Humidifier Dry Colorado winter air — sinus, static, cracking wood floors / furniture.

Filter Upgrade (MERV / Media Cabinet) Higher MERV or 4" media cabinet for better air quality & longer change cycle.

UV / UVC Light (Cleaner Air) Kills mold & bacteria on coil and in airstream. Good for allergies / odors.

Duct Cleaning / Sealing Heavy dust, uneven rooms, post-construction, pet hair, rodent activity.

JL Maintenance Plan Priority service + spring/fall tune-ups + discount on repairs.

Upsell Notes / Quoted Items

15. Cleanup & Closeout

Remove trash, debris, screws, packaging, and used materials.

Wipe work area and make it cleaner than when you arrived.

Take final photos of clean equipment and readings.

Set thermostat back to the customer’s preference.

“Everything has been serviced and tested. I checked the burners, heat exchanger, gas and combustion, electrical, airflow, venting, and temperature rise — and the furnace is operating safely and properly at this time. Is there anything else you’d like me to look at while I’m here?”

“Thank you. Stay warm.”

Final Pass

Safe (gas + electrical + venting)

Heat exchanger inspected — no CO concern

Combustion checked

Clean & reassembled

Running properly

Client informed + photos done

Job Info