Annual boiler service
Annual · typically September
Why it matters
Boilers are the longest-lived heat in the business — 30-year-old ones run fine all over the country — but only when someone lays eyes on them once a year.
Learn one thing from this card: the pressure gauge. A typical residential hot-water boiler sits around 12–15 psi cold. If yours creeps toward 25–30, or the relief valve is dripping into a bucket someone left there, the system is telling you something a $200 visit can fix and a year of ignoring can't.
What skipping it costs
$600–$8,000
Boilers fail quietly: a waterlogged expansion tank spikes the pressure, the relief valve weeps for a year, and the constant fresh-water makeup rots the boiler from the inside. The $200 fall service catches it; skipping it is how a $600 repair becomes an $8,000 boiler replacement in January.
Two ways to get it done
Do it yourself
You'll need: Flashlight.
Your part is a monthly 60-second walk-by, plus prep for the tech:
- Read the pressure gauge cold and note it. Same number every month is good news. Climbing is not.
- Look under the relief valve (the pipe running toward the floor). Dripping or crusted white? Mention it when you book — that's the expansion tank talking.
- Check for rust streaks or wet spots at pipe joints and under the boiler.
- Keep the area clear — no paint cans or boxes against a burner.
- Book the service in September, before the season. In your county, the techs who are easy to schedule now are booked solid the first cold week.
That's it. Combustion adjustment, water treatment, and anything involving the burner is licensed-tech territory.
Hire it out
$150–$300National fair range — local labor moves this number.
A real annual service runs $150–$300 and takes about an hour: burner cleaned and tuned, combustion tested with numbers on the invoice, pressure and expansion tank checked, relief valve tested, low point drained until it runs clean.
The classic upsell is the funeral pitch: relief valve dripping, tech shakes his head, "these old boilers, you're living on borrowed time." Nine times out of ten a dripping relief valve is a waterlogged expansion tank — a cheap part and an hour. Make anyone pitching replacement show you the failure: combustion numbers out of range, a pressure test it can't hold, or visible water where water shouldn't be.
Ask the tech
- What's the pressure reading cold, and what should it be for my system?
- Did you check the expansion tank and the relief valve, not just the burner?
- How's the water quality — any sludge when you drained the low point?
Red flags you're being upsold
- A 'your boiler is shot' verdict off a dripping relief valve — that's usually a $30–$150 expansion tank problem, not a $9,000 boiler.
- A replacement quote at the first visit with no combustion test numbers on paper.
- Anyone who services the burner but never looks at the pressure gauge or expansion tank — that's half a service.
Second opinion time: Any replacement quote over $6,000, or any 'cracked heat exchanger / cracked section' claim without a pressure-loss test or dye evidence you can see.
The call
Hire the annual service — combustion and pressure work isn't DIY. Your job is the monthly glance at the pressure gauge, and this card teaches you what it should say.