No heat, a leak, or a boiler that will not stay on
A cold house is hardest on a cold night. Pipes in outside walls can freeze within hours once the house cools, and a frozen pipe becomes a second emergency on top of the first. A leaking boiler is a separate urgent case, because water on a hot unit can mean a failed tank or a loose fitting.
Tell dispatch what the boiler is doing: silent, clicking, lighting and shutting off, or dripping. The answer decides what the plumber brings. Keep in mind that some systems burn oil, and burner work then needs a licensed oil burner technician, not a plumber.
Safe things to do while you wait:
- Leave the house and call 911 if you smell gas or a carbon monoxide alarm is sounding.
- Check that the thermostat is set to heat and the boiler switch and breaker are on.
- Look at the pressure gauge. Note the reading, but do not add water if you smell gas.
- Open cabinet doors on outside walls, and let taps drip slowly if pipes might freeze.
- Do not open the boiler cabinet or touch hot pipes. Keep children and pets away.
Carbon monoxide and gas safety come first
A boiler that burns gas or oil can produce carbon monoxide if it vents badly or burns poorly. The gas has no smell, so a working CO alarm on every level of the house is the only warning. Soot around the unit, a yellow flame or a vent pipe that has come loose are all signs to shut it off.
If an alarm sounds, get everyone outside, call 911 and do not go back in. A suspected gas leak is a call to your gas utility and 911 before anyone calls a plumber. Once the house is safe, we can inspect the boiler and the piping.
Symptom, likely cause, what happens next
Most heating calls fall into a few patterns. This table shows the usual cause behind each one.
| Symptom | Likely cause | Typical fix |
|---|---|---|
| No heat, boiler silent | No power, tripped limit switch, failed circulator or ignition fault | Reset power, test the circulator, replace the failed part |
| Radiators or baseboard cold upstairs | Air trapped in the loop or low pressure | Bleed the loop and check the fill valve |
| Pressure drops or climbs high | Waterlogged expansion tank or a failing fill valve | Replace the tank or valve and set the pressure |
| Water pooling at the boiler | Leaking fitting, relief valve or cracked heat exchanger | Tighten or replace the part, or replace the boiler if the vessel failed |
| Banging, kettling or gurgling | Mineral scale or trapped air | Flush the boiler and bleed the system |
| Hot water from the boiler but no heat | Zone valve stuck or thermostat call lost | Replace the zone valve or check the wiring |
Low pressure, high pressure and the expansion tank
A hot-water boiler is a closed loop with a set operating pressure, commonly 12 to 15 psi when cold. A gauge that reads near zero means water has been lost to a leak or an open valve. A gauge that climbs past 25 or 30 psi when hot, and sends water out of the relief valve, usually points to a failed expansion tank.
The expansion tank has a rubber diaphragm that cushions the water as it heats and expands. When the diaphragm fails, the tank fills with water, the pressure spikes and the relief valve may open. A plumber can test it, recharge it or replace it in a single visit.
Adding water to a boiler with an unknown leak only delays the problem. The same goes for repeated refilling. If you keep topping up pressure, call us to find the leak before it damages the unit.
Call the 24/7 line. Tell dispatch the boiler type and what it is doing, and whether anyone smelled gas.
Cast iron, steel and what that means for repair
Older homes often have a cast iron boiler, built from heavy sectional castings. They last for decades and tolerate hard use, but a crack in a section is rarely worth fixing. Steel boilers are lighter, heat faster and are more sensitive to water quality, since poor water chemistry and oxygen speed up rusting.
Modern high-efficiency condensing boilers are more complex and depend on drains for acidic condensate. They often run at lower water temperatures than a cast iron boiler, which can matter if the baseboard was sized for hotter water.
When a boiler is old and has multiple problems, replacement can cost less than a string of repairs. We give you the repair and replacement options with a clear price before work starts, and new boiler piping is covered by the same permit rules as other plumbing installation work.
Heating in Milford, MA houses
Milford winters are long enough that a boiler works hard from fall to spring. A unit that has run through many seasons may need cleaning, flushing and an inspection before the first cold snap, since a small fault found in October is cheaper than an emergency in January.
Hot-water baseboard is common in New England homes. It relies on a loop of copper pipe with fins, and a dent, a kink or a single closed valve can leave one room cold. Before a repair, check that furniture is not blocking the baseboard and that every zone valve is open.
Under the state's consumer guidelines, a licensed plumber may also do gas fitting, but oil burner work is a separate licence, so ask which one your boiler needs.
Licensing: gas, oil and who does what
In Massachusetts a licensed master or journeyman plumber may also do gas fitting, and our plumbers are licensed and insured. Plumbing and gas work on a boiler needs a permit from the local inspector. Oil burner service is a separate licensed trade, so for an oil-fired burner we tell you plainly when to call an oil burner technician.
Replacing a boiler or altering its piping needs a permit and an inspection. Ask to see the permit and ask the Milford plumbing inspector through Town Hall if you are unsure.
What decides the cost of boiler repair
The real number comes from a call. These factors move it:
A sudden pipe burst from a frozen line may be covered by homeowner insurance, while normal wear on a boiler usually is not. Check your policy.
For a clear price on your boiler, call (508) 389-4045 and describe the symptoms.
Boiler repair questions from Milford homeowners
Yes. The line is answered 24 hours a day through winter nights, weekends and holidays. No-heat calls are dispatched as emergencies, and we tell you plainly if an oil burner technician is also needed.
A slow loss usually means a leak or a failed fill valve. Look for wet spots at fittings and the relief valve. Topping up without finding the cause only delays the repair.
It absorbs the extra volume as water heats, which keeps pressure steady. A failed tank causes pressure spikes and a relief valve that opens.
It depends on the failure. A circulator or valve is a worthwhile repair. A cracked heat exchanger or section usually is not, and we explain both options.
Radiators and baseboard loops can be bled when the boiler is off and cool. If you smell gas or are unsure, leave it for a plumber.
Minor repair of a working part may not, but work on piping, gas or a replacement does. Ask the Milford plumbing inspector through Town Hall, and permits go only to licensed plumbers.
Our plumbers handle the water side. Oil burner service requires a licensed oil burner technician, and we will say so before work starts.
Not sure what your boiler is telling you? Call (508) 389-4045 and describe the gauge, the sounds and any leaks.
If the problem is not the boiler
A boiler that also heats your domestic water may point to a water heater repair question, and frozen pipes after a cold night are a burst pipe repair job. Houses in Bellingham use the same line, and a heating leak may be traced with leak detection.