Boiler Repair in Boulder, CO
Boulder's older housing stock, especially homes built before the 1970s, still runs a lot of hydronic (boiler-based) heat rather than forced air. Boulder Express Plumbing repairs boilers alongside our standard plumbing work, which matters because a boiler problem is often actually a plumbing problem, low water pressure in the loop, a failed expansion tank, or a leaking valve.
Why It Happens Here.
A boiler system that's original to a pre-1970s Mapleton Hill or University Hill home has had decades for mineral buildup, sediment, and small leaks to accumulate in the loop. That's different from a furnace repair call, and it's worth working with someone who treats it as a plumbing system, not just an appliance.
Boulder's water carries enough mineral content that scale buildup inside an old boiler's heat exchanger is a genuine efficiency drag over time, not just a cosmetic issue. A system running harder than it should to hit the same temperature is often scale, not a failing burner.
Signs to Watch For.
Radiators or baseboard heat that stay cold while the boiler runs.
Banging, knocking, or kettling sounds from the boiler.
Low or fluctuating pressure gauge reading.
Water pooling near the base of the unit.
Pilot light or ignition issues on an older gas boiler.
Noticeably higher heating bills without a change in usage.
Need Help Right Now?
A licensed technician can be dispatched today.
How We Track Down the Cause.
We check system pressure, the expansion tank, and circulator pump function before assuming a part has failed outright. A boiler that won't hold pressure usually has a leak somewhere in the loop, and finding that leak comes before any part gets replaced.
If the system holds pressure fine but heat output still feels weak, we look at scale buildup in the heat exchanger and check whether zone valves are actually opening and closing when they should. A boiler can run constantly and still underheat a home if a valve is stuck.
Your Repair Options.
Component Repair.
- Circulator pump, expansion tank, pressure relief valve, or zone valve replacement.
- Right call when the boiler itself is structurally sound.
- Usually same-visit.
Full System Flush.
- Clears sediment and mineral buildup from an older loop.
- Improves heat transfer and reduces banging/kettling noise.
- Worth doing on a system that hasn't been serviced in years.
What This Actually Costs.
We don't publish flat prices because the factors above genuinely change the number. Free on-site estimates cover non-emergency work, and for active emergencies we give you an upfront price before any repair begins. Call (303) 552-3896 for your real number.
Questions We Get Often.
Usually both at once. A radiator that stays cold while the boiler runs is often a stuck zone valve or trapped air in the loop, which is genuinely plumbing work, not just an appliance repair.
There's no single number that fits every system, since it depends on water hardness and how long it's been since the last service. If you don't know the last time yours was flushed and the heat feels weaker than it used to, that's worth having checked. A flush is also a reasonable thing to schedule alongside any other boiler repair while a technician is already there.
That depends on the age, the specific failure, and whether parts are still available. A leak in a component like a circulator pump or expansion tank is almost always worth repairing. A cracked heat exchanger on a very old unit is a different conversation, and we'll be straight with you about which one you're facing.
Often Booked Together
A plumbing issue unrelated to the boiler itself, found during the same visit, is covered under general plumbing repair. Homes with both a boiler and a separate domestic water heater sometimes need water heater repair too, and commercial properties with boiler systems can bundle service under commercial plumbing.
If your boiler is making noise, running cold, or losing pressure, call Boulder Express Plumbing. We treat it as the plumbing system it actually is, not just a furnace swap. Our technicians work on hydronic systems regularly, not as an occasional add-on to furnace calls.