Boiler Repair, Service & Replacement in Longmont, CO
Hydronic heat is quiet, even and comfortable, right up until the boiler quits. Our technicians repair, maintain and replace boilers of every brand, around the clock.
Boiler Experts for Longmont's Hydronic Homes
Plenty of homes in Longmont’s older neighborhoods, along with newer custom builds, heat with hot water instead of forced air. Boilers feed radiators, baseboard units and radiant floor loops with steady, draft-free warmth. They are durable and quiet, but they are also a different animal from a furnace, and not every HVAC company is comfortable working on them.
M&M Heating, Cooling, Plumbing & Electrical has serviced boilers across the Front Range since 1996. Our licensed, insured, NATE-certified technicians handle boiler repair, annual maintenance, and full replacement or retrofit for all brands, from cast-iron workhorses to modern high-efficiency condensing boilers. Because we are also a plumbing company, we are equally at home with the piping, pumps, zone valves and expansion tanks that make a hydronic system work.
Local conditions matter here. Hard water scales up heat exchangers and causes the rumbling known as kettling, dry air and seasonal temperature swings stress pressure and expansion components, and altitude affects combustion on gas-fired boilers. We see these issues every winter and know how to address them.
Whether you need an emergency repair at 2 a.m., a pre-season tune-up, or honest advice on replacing a boiler that has reached the end of the road, you get upfront pricing, no overtime rates and our 100% satisfaction guarantee. New boiler installations are backed by the One Year Test Drive, and financing is available. If your boiler feeds in-floor heat, see our radiant floor heating page as well.
Common Boiler Problems We Fix
Boilers tend to give warning before they fail. These are the signs worth a call.
Radiators or Baseboards Stay Cold
If the boiler fires but some or all of the house stays cold, suspect a failed circulator pump, a stuck zone valve, air trapped in the lines or a thermostat problem. One cold zone usually means a zone issue; the whole house usually means the pump.
Banging, Rumbling or Kettling
Kettling sounds like a giant tea kettle and is caused by mineral scale from our hard water building up on the heat exchanger. Banging in the pipes often means air in the system or a circulator problem. Both are fixable, and both get worse if ignored.
Pressure Too Low or Too High
A boiler that keeps losing pressure has a leak or a failing fill valve. Pressure that climbs until the relief valve discharges points to a waterlogged expansion tank. The pressure gauge is your boiler's best early warning.
Water Leaking Around the Boiler
Leaks come from the relief valve, pump flanges, pipe joints or, worst case, the heat exchanger itself. Catching a small leak early protects the floor, the boiler and the mechanical room from damage.
Pilot Out or Ignition Failure
A pilot that will not stay lit or an electronic igniter that clicks without firing usually traces to a thermocouple, flame sensor, gas valve or control module. Do not keep relighting it. Let us find out why it is going out.
Error Codes, Lockouts or Short Cycling
Modern boilers lock out to protect themselves. Repeated lockouts, a boiler that cycles on and off rapidly, or a yellow flame instead of blue all call for a technician with the right diagnostic tools before the system quits for good.
The M&M Difference
Boilers need technicians who understand both combustion and plumbing. We have both under one roof.
Trained on Hydronic Systems
Our NATE-certified, licensed and insured technicians work on boilers every winter, not once in a while. Cast iron, steel, copper fin, condensing: we know the differences and carry the parts.
Heating and Plumbing in One Call
Circulators, zone valves, expansion tanks, backflow preventers and the gas line feeding the boiler all fall within our licensed trades. You do not need two contractors to fix one system.
24/7 Boiler Repair, No Overtime
A boiler failure during a cold snap risks frozen pipes on top of a cold house. We answer around the clock and charge the same upfront price on nights, weekends and holidays.
Guaranteed Work, Guaranteed Installs
Every repair carries our 100% satisfaction guarantee. New boiler installations are backed by the One Year Test Drive, and financing is available on new equipment.
Our 4-Step Process
Whether it is a repair, a tune-up or a replacement, every boiler visit follows the same straightforward path.
Call and Describe the Problem
Tell us what the boiler is doing: no heat, noise, leaking, pressure readings or error codes. Emergencies are dispatched immediately. Maintenance and estimates are scheduled at your convenience.
Full-System Diagnosis
Your technician checks the burner and ignition, pressure and expansion tank, circulators, zone valves, venting and controls, then traces the fault to its source rather than the symptom.
Upfront Price and Options
You get a written price for the repair before work begins. If the boiler is old and the repair is significant, we also show you what a replacement would cost so you can decide with both numbers in hand.
Repair, Purge and Verify
We complete the work, purge air from the system, set the pressure correctly and run the boiler through a full cycle on every zone before we leave. Heat on, mess gone.
Boiler Questions From Longmont Homeowners
How long do boilers last?
Longer than most heating equipment. A well-maintained cast-iron boiler can run for decades, and modern condensing boilers typically last 15 to 20 years or more. The key words are well-maintained. Hard water scale, neglected pressure problems and skipped annual service all shorten the life considerably. If your boiler is old but healthy, there is no reason to replace it just because of its age.
Should I repair or replace my boiler?
Repair when the problem is a single component such as a pump, valve, igniter or expansion tank, and the boiler itself is sound. Replace when the heat exchanger is leaking, repairs are becoming frequent, parts are no longer available or the efficiency gap is costing you real money every winter. We give you an honest comparison with upfront pricing on both paths and a free second opinion if someone else has told you to replace.
Does my boiler need annual maintenance?
Yes. Boilers should be serviced every year before heating season. A boiler tune-up includes checking combustion and venting, testing safety controls and the relief valve, verifying system pressure and the expansion tank, inspecting the circulator and zone valves, and cleaning the heat exchanger of scale and soot. Annual service also keeps most manufacturer warranties valid. Ask us about Loyalty Club discounts and priority scheduling for boiler service.
What is kettling and is it dangerous?
Kettling is the rumbling or banging sound a boiler makes when mineral scale from hard water insulates the heat exchanger and causes water to flash to steam inside it. It is common along the Front Range because of our water. It is not an immediate danger, but it stresses the heat exchanger and lowers efficiency. The fix ranges from a descaling treatment to heat exchanger replacement, depending on how far it has progressed.
Why does my boiler keep losing pressure?
A hydronic system is closed, so pressure should stay steady. If it keeps dropping, water is leaving the system somewhere: a dripping relief valve, a leaking pipe joint or radiator valve, a failed automatic fill valve or a pinhole in the heat exchanger. Topping it up with the fill valve treats the symptom and adds fresh oxygen and minerals that cause corrosion. Let us find and fix the actual leak.
Can you replace an old boiler with a high-efficiency model?
In most homes, yes. High-efficiency condensing boilers extract more heat from the same gas and can often use the existing radiators and piping, though venting and condensate drainage are different and need to be designed properly. We size the new boiler to your home's heat loss, handle the gas, venting and plumbing in one project, and back the installation with our One Year Test Drive. Financing is available, and we will let you know about any available utility rebates.
Boiler Trouble? Call the Hydronic Experts
Open 24/7 | Emergency Service Available
Call (720) 608-3973Boiler Service Across the Front Range
Proudly serving Longmont, CO and surrounding communities.
Primary Service Area
- Longmont, CO
- Erie, CO
- Frederick, CO
- Firestone, CO
- Dacono, CO
Extended Area
- Mead, CO
- Johnstown, CO
- Berthoud, CO
- Niwot, CO
- Gunbarrel, CO
Also Serving
- Lafayette, CO
- Louisville, CO
- Superior, CO
