What Eight Months of Sitting Does to a Furnace
The intuitive assumption is that a furnace used three weeks a year should last forever. In practice, the Valley heating failure pattern is dominated not by wear but by dormancy. Dust settles into places it does not settle in a system that runs. Rubber tubing on pressure switches hardens. Flame sensors oxidize. Rodents, looking for shelter, find flue terminations and equipment closets remarkably attractive during the summer.
Every one of those conditions is invisible until the system is asked to run — which is why our call volume for no-heat spikes into a wall during the first cold snap of the season. Everyone finds out at the same time, which is also the moment when every HVAC company in the metro is running a backlog.
A fall tune-up moves that discovery to a Tuesday in October when it is a scheduled visit rather than an emergency. The work is the same. The difference is whether you are choosing the appointment or the weather is choosing it for you.
What Gets Checked and Measured
Every reading recorded and handed to you, so you can compare against last year rather than taking our word for it.
Combustion and Safety
Heat exchanger inspection, combustion analysis, flue draft and venting condition, combustion air verification, gas leak check at the valve and connections, and carbon monoxide measurement in the living space. This is the part that is genuinely about safety, not efficiency.
Ignition System
Flame sensor cleaned to bare metal and its microamp signal measured, hot surface ignitor resistance tested against specification, burner condition and flame pattern inspected, and the full ignition sequence observed start to finish.
Gas and Airflow
Manifold gas pressure verified with a manometer, temperature rise measured across the heat exchanger and compared to the nameplate range, blower wheel condition checked, filter inspected, and static pressure measured.
Controls and Safeties
Pressure switch operation, high-limit and rollout switch function, inducer motor amp draw, control board sequencing, thermostat calibration, and every electrical connection checked and tightened.
Heating-Mode Service for Heat Pump Homes
A large share of Valley homes heat with a heat pump, and a cooling tune-up does not cover the heating side of that equipment.
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1
Reversing Valve Operation
The reversing valve is what flips the system between cooling and heating. It sits idle in one position for most of the year and can stick. We command a heating cycle and verify the valve actually shifts, rather than assuming it will when December arrives.
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2
Defrost Cycle Verification
On cold Valley mornings a heat pump coil can frost, and the defrost control has to initiate and — equally important — terminate the cycle correctly. A defrost board that initiates but does not terminate properly runs the auxiliary heat far more than necessary and shows up as a startling power bill.
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3
Auxiliary Heat Strip Testing
Electric heat strips are backup heat, and they consume a great deal of power. We confirm they energize when genuinely called for, and we confirm they are not energizing on every call for heat because of a miswired or misconfigured thermostat — a surprisingly common and expensive fault.
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4
Refrigerant Charge in Heating Mode
A heat pump that is slightly low on charge cools acceptably in summer and heats poorly in winter, because heating mode is less forgiving of a marginal charge. Verifying it in the fall catches the problem before it becomes a cold-morning complaint.
Straight Answers About Furnace Tune-Ups
When should I get a furnace tune-up in Phoenix?
October or early November, before the first genuinely cold morning. Valley furnaces sit unused for eight months and the failures that idle time creates only surface on the first call for heat — usually at the same moment everyone else is discovering theirs.
Do I need heating maintenance if I barely use my heat?
Yes, arguably more than someone who uses it constantly. Idle equipment is where dust settles on flame sensors, pressure switch hoses clog, rodents nest in flues, and rubber components dry out. A furnace used three weeks a year surfaces all its problems at once.
What does a heating tune-up include?
Heat exchanger inspection, combustion analysis, CO testing, flame sensor cleaning, ignitor testing, gas pressure verification, temperature rise measurement, flue and venting inspection, safety interlock testing, blower and airflow check, and electrical tightening — with all readings written down for you.
How do I know if my heat exchanger is cracked?
Usually you cannot tell from the outside, which is why it gets inspected. Warning signs: a persistent chemical odor, soot around burners, flames that roll or flutter when the blower engages, and unexplained headaches or nausea when the heat runs. Shut it off and call if you suspect it.
Do heat pumps need heating-mode maintenance too?
Yes, and it differs from a cooling tune-up — reversing valve operation, defrost initiation and termination, and auxiliary heat strip behavior. Heat strips running when they should not be are one of the biggest hidden power bills we find.
Book a Fall Tune-Up
Find the problem in October on a scheduled visit instead of at 6 a.m. on the first cold morning of the year.
(602) 512-1138