Knowing the sequence of operation on a gas furnace will help you diagnose it right the first time - saving time and money on troubleshooting calls.
The sequence of operation may vary depending on type or brand. But for the most part, manufacturers mostly use a hot surface or direct spark ignition.
The sequence of operation is as follows:
1. Heat call from the thermostat
2. Control board does a safety check (limit switches, roll out switches)
3. Inducer motor comes on
4. Pressure switch must close to go to the next step
5. Hot surface ignitor begins getting hot / direct spark ignitor begins to spark
6. Gas valve opens
7. Furnace lights
8. Flame sensor senses flame
9. Blower motor comes on between 30 seconds to 1 minute
10. Once thermostat is satisfied, the burner shuts off
Thanks for watching!
Feel free to use the affiliate links below if you’d like to help support the channel. I make a very small commission if you purchase through the links - Thanks!
TOOLS I USE
15% off code: HTK15
Kaiweets KC602 clamp meter: [ Ссылка ]
EDC Tools
SOGCASE Leather EDC Belt Multitool Organizer - [ Ссылка ]
Milwaukee 550 lumens light - [ Ссылка ]
Milwaukee Fastback 6In1 Folding Utility Knife - [ Ссылка ]
Milwaukee Compact Tape Measure - [ Ссылка ]
KNIPEX Tools
KNIPEX Electricians' Shears - [ Ссылка ]
KNIPEX 7-1/4-Inch Cobra Pliers - [ Ссылка ]
KNIPEX Long Nose Pliers With Cutter - [ Ссылка ]
KNIPEX 8-Inch High Leverage Angled Diagonal Cutters - [ Ссылка ]
Socket Sets, Bits & Bit Holders
Klein Tools 65200 Ratchet Set, 5-Piece Mini Ratchet Set - [ Ссылка ]
Klein Tools 3-in-1 Impact Flip Socket - [ Ссылка ]
Klein Tools 11-in-1 Multi-Bit Screwdriver/Nut Driver - [ Ссылка ]
1/4 Inch Hex Shank Drill Bits Holder/Organizer Tool - [ Ссылка ]
Klein Tools 7-in-1 Impact Flip Socket Set - [ Ссылка ]
Klein Tools 14-in-1 Magnetic Multi-Bit Screwdriver Set - [ Ссылка ]
Klein Tools 7-in-1 Magnetic Nut Driver (1/4 to 9/16-Inch) - [ Ссылка ]
StealthMounts Milwaukee M12 Magnetic Bit Holder - [ Ссылка ]
Milwaukee M18 Combo Kit - [ Ссылка ]
MultiMeters
Testo 770-3 Digital MultiMeter - [ Ссылка ]
Fieldpiece SC680 - Wireless Power Clamp Meter - [ Ссылка ]
Fluke 87V Digital Multimeter - [ Ссылка ]
Manometer
Fieldpiece JL3KM2 Job Link Dual Manometer Kit - [ Ссылка ]
Wireless HVAC Probes
Fieldpiece JL3KH6 HVACR Charge and Air Kit - [ Ссылка ]
Testo Bluetooth Smart Probe Kit - [ Ссылка ]
Combustion Analyzers/ Flue Gas Detectors
Testo Residential Combustion Analyzer Kit - [ Ссылка ]
Propane & Gas Leak Detector/Sniffer - [ Ссылка ]
HVAC Tool Bags & Backpacks
Klein Tools Tool Bag Backpack - [ Ссылка ]
Milwaukee Packout Compact Tool Bag - [ Ссылка ]
Milwaukee Packout Heavy Duty Tool Bag - [ Ссылка ]
AWP Extreme Heavy-Duty Tool Bag Backpack - [ Ссылка ]
VETO Tool Bags
Veto Pro Pac TECH-MC - [ Ссылка ]
Veto Pro Pac MB2 Tool Pouch - [ Ссылка ]
Veto Pro Pac TP3 Tool Pouch - [ Ссылка ]
Veto TP4-B Hard Plastic Base Tool Pouch - [ Ссылка ]
Veto Pro Pac MB3B Meter Bag - [ Ссылка ]
Milwaukee Packout
Milwaukee Packout 3-Drawer Tool Box - [ Ссылка ]
Milwaukee Packout 10 in. Compact Tool Box - [ Ссылка ]
Milwaukee Packout Compact Organizer - [ Ссылка ]
Milwaukee Packout Deep Organizer - [ Ссылка ]
Milwaukee Packout Compact Low Profile Parts Organizer - [ Ссылка ]
Milwaukee Packout Crate - [ Ссылка ]
Milwaukee M18 Fuel Packout Wet/Dry Vacuum - [ Ссылка ]
Milwaukee Packout 3-Drawer Tool Box - [ Ссылка ]
Digital Thermometers
Klein Tools Pocket Size Digital Thermometer - [ Ссылка ]
Fieldpiece Pocket Size Digital Thermometer - [ Ссылка ]
UEi Pocket Size Digital Thermometer - [ Ссылка ]
Testo 835-T2 Infrared Thermometer - [ Ссылка ]
Thermal Cameras
TOPDON TC003 Touch Screen Thermal Imaging Camera - [ Ссылка ]
FLIR ONE Pro - iOS - Thermal Camera - [ Ссылка ]
Seek Thermal CompactPRO Thermal Imaging Camera - [ Ссылка ]
Coil Cleaning
Port A Blaster HVAC Coil Cleaning Washer - [ Ссылка ]
Nu-Calgon Evaporator Coil Cleaner - [ Ссылка ]
CoilShot Condenser Cleaner Tool - [ Ссылка ]
Anemometers
Testo 416 Digital Mini Vane Anemometer - [ Ссылка ]
Air Flow
Testo 420 Balometer kit with flow hood - [ Ссылка ]
CPS ABM-HOOD-200 Easy Air Flow Balancing Hood - [ Ссылка ]
![](https://i.ytimg.com/vi/1JWZjLp-mwI/maxresdefault.jpg)