Tune-up season is good for business. People either fired up the heat and something went sideways, or they’re being proactive. Doesn’t matter which: You’re getting the call either way. The techs who run the same, thorough inspection every time are the ones who find the problem before it becomes a midnight callback.
Here’s a fall HVAC tune-up checklist to follow.
☑ Heat exchanger
On a gas furnace, don’t skip this. A cracked heat exchanger puts combustion gases in the living space. Look at it carefully and run a combustion analyzer if you’ve got one. If something looks off, that conversation must happen before anything else.
☑ Ignition system
Hot surface igniters crack and fail, often without much warning. Look for visible damage and pull resistance with a multimeter. Silicon nitride igniters typically read 40 to 90 ohms cold, so anything outside that range or showing physical cracks should get replaced. A $20 igniter on a tune-up is a lot better than a return visit in January.
Older system with a standing pilot? Check the flame color and height. Yellow or lazy flame usually points to a dirty orifice or a gas pressure problem.
☑ Gas valve and manifold pressure
Pull the pressure and compare it to the nameplate. A valve drifting out of spec will cause ignition problems, short-cycling or incomplete combustion. While you’ve got the detector out, check every fitting for leaks. This one’s non-negotiable.
☑ Blower motor
Check amps against nameplate FLA, look at belts on belt-drive units and lube the bearings on anything that isn’t sealed.
☑ Capacitors
Low microfarads means it’s going to fail, just a matter of when.
☑ Contactor
Pitting or burn marks means it’s due for replacement.
☑ Flue and venting
Check for blockages, corrosion or anything that’s come apart.
☑ Filter
Swap it or write it up for the customer.
☑ Limit switch
Make sure it’s tripping in the right range
☑ Fire it up
Run the system through all stages. Check temperature rise across the heat exchanger — most furnaces are spec’d at 35 to 70 degrees — and make sure the thermostat cycles correctly and the safeties respond. Write it all down and leave the customer a copy.
Do it the same way every time and you’ll have fewer callbacks and more referrals.
System Aire and Control Aire stock the igniters, capacitors, contactors, gas valves you’ll need on these calls. Reach out to your local branch for same-day pick up or next-day delivery, or shop our inventory at sascocasco.com.