This boiler repair guide for Dedham, MA is built around one question: the house is cold, so what can you safely check before calling? A boiler is a sealed heating appliance that warms water (or makes steam) and sends it to radiators, baseboard or in-floor loops.
Most no-heat calls trace back to a short list of causes, and several of them take two minutes to rule out. Others involve gas, combustion and pressure, and those belong to a licensed professional.
Read this first: gas smell and carbon monoxide.
If you smell gas inside, leave the building right away. Call 911 from outside, then call your gas utility. The Mass.gov gas safety guidance says not to turn lights or appliances on or off, not to open or close windows, and not to try to shut off the gas yourself. Do not go back in to look for the source.
Carbon monoxide has no smell. Any fuel-burning boiler can produce it if venting or combustion goes wrong. Working CO alarms on every level and outside bedrooms are the practical defense. If an alarm sounds, or you feel headache, dizziness or nausea that eases when you go outdoors, get everyone out and call 911.
Never relight a boiler that has repeatedly shut down, and never bypass a safety control to make it run.
Five-minute no-heat triage.
- Check the thermostat. Confirm it is set to heat, the setpoint is above the room temperature, and the batteries are fresh..
- Check power. Look for a tripped breaker and the boiler's own service switch, which often looks like a light switch near the unit..
- Check fuel. If you have an oil tank, read the gauge. For gas, other gas appliances like the stove burner can tell you whether gas is reaching the house. If neither works, call your gas utility..
- Read the pressure gauge. Most residential hot-water systems sit in a modest range when cold, and the manual or label on your boiler gives the exact number. A reading near zero suggests a leak or lost water..
- Look for a lockout light or error code and write it down for the plumber..
If all five look normal and the boiler still will not fire, stop. Do not open the burner or combustion area.
No heat and the checks did not help? Call the 24/7 line.
Call (617) 752-0573What the symptoms usually suggest.
| Symptom | Possible cause | Safe homeowner step. |
|---|---|---|
| No heat, boiler silent | Power, thermostat or safety lockout | Thermostat and breaker checks. |
| Boiler runs but radiators stay cool | Air in the system or a circulator problem | Bleed the cooler radiators. |
| Banging or kettle-like noise | Scale, low water or a failing pump | Turn it off and call. |
| Pressure keeps dropping | A leak somewhere in the loop | Look for wet spots, then call. |
| Pressure climbs high or relief valve drips | Expansion tank or fill valve trouble | Turn it off and call. |
| Puddle under the boiler | Leaking fitting, valve or the boiler itself | Shut off water to it and call. |
Bleeding a radiator: what is reasonable.
If radiators are cold at the top and warm at the bottom, trapped air is the usual reason. On a hot-water system with radiators, a homeowner can often bleed them with a radiator key. Turn the system off first. Open the bleed valve a quarter turn with a rag held below it, close it when water appears, and check the gauge afterward.
Do not do this on a steam system. Steam radiators use different valves and the water is hot enough to scald. If you are not sure which type you have, look at the pipes and the manual, or ask the plumber. When the gauge drops after bleeding, the system may need water added. If you do not know how to add it safely, wait for a technician.
When to stop and call.
Call a licensed plumber when the boiler smells of fuel, shows soot or scorch marks, trips its safety lockout repeatedly, leaks, makes banging sounds, or loses pressure again after you refill it. The same goes for any repair that needs the burner, gas valve, venting or electrical controls opened. These are not casual jobs, and Massachusetts reserves plumbing and gas fitting work to licensed professionals.
Many older New England homes heat with hot-water boilers, though we do not have a Dedham figure for how many. Because the details vary house by house, a plumber should look at the actual equipment. Our boiler repair page explains how a no-heat visit is handled, including what to tell the dispatcher.
What Dedham homeowners should know.
NOAA's 1991 to 2020 climate normals for the Boston area (the Logan Airport station, not a Dedham station) put the January average low at 23.1 degrees Fahrenheit and February at 24.6. That is a long run of nights where a dead boiler becomes a real problem within hours.
If the house starts to cool, open interior doors, close off unused rooms and keep the warmest room in use while you wait for repair.
The Master Plan "Designing Dedham 2035" reports that 74 percent of Dedham houses were built before 1978. For you, that means the heating equipment and the piping around it may be older than the boiler itself, so a technician should look at valves, supply lines and the condition of old connections while on site.
Two code points apply to boiler work. Mass.gov states that permits for plumbing work are issued only to licensed plumbers. The safe waste pan policy applies to boilers of 6 gallons or more installed above an occupied space, with the pan piped to a trapped fixture or within 12 inches of the floor. If your boiler is being replaced, ask the plumber how the pan and permit are handled.
Keep the house safe while you wait.
- Close the doors of rooms you do not need and keep the family in one room.
- Never use a gas oven, stove burner or outdoor grill to heat the home, because they produce carbon monoxide.
- If rooms get cold enough that pipes could freeze, ask the plumber on the phone whether to shut off the water and drain the lines.
- Check on older neighbors and relatives who may not tell you they are cold.
- Keep the boiler area clear of boxes and chemicals.
If pipes do freeze, our leak detection page covers finding where water is escaping after a thaw.
Nearby towns.
Heating failures are common to the whole area. Whether your home is in Needham or Walpole, the same triage and safety rules apply. Ask your own utility and building department about local requirements.
Frequently asked questions.
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The burner may be firing, but heat is not moving. Trapped air, a stuck circulator pump, a closed valve or a zone issue can all cause it. Bleed radiators if you have hot water radiators, check that zone valves are not stuck closed, and call if nothing changes.
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Usually one reset is acceptable if the manual allows it. If the boiler locks out again, stop. Repeated lockouts point to a safety device doing its job, and forcing it can be dangerous.
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Test another gas appliance. If the stove burner also fails, call your gas utility. If gas is smelled, leave the building and call 911 from outside first.
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Mass.gov says plumbing permits are issued to licensed plumbers by the local inspector. Ask the Dedham Building Department's Plumbing/Gas Division and your plumber how the permit is handled for your project.
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Tenants should contact the landlord or property manager immediately, because the owner usually decides who is called. If you cannot reach them, ask about emergency dispatch and tell the owner what you found. Keep a written record of times and temperatures.
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A combined system means no heat may also mean no hot water. If hot water is the only problem, a separate check of the tank or indirect heater is needed. Mention both symptoms when you call.
Codes, standards and sources.
Plumbing work in Massachusetts is governed by 248 CMR 10.00, the Uniform State Plumbing Code, and plumbers are licensed by the Board of State Examiners of Plumbers and Gas Fitters. You can read the state's consumer fact sheet on plumbers and gas fitters before you hire anyone.
Local facts on this page come from the Dedham-Westwood Water District, the Town of Dedham, the other towns named and Mass.gov, and were checked in October 2026. Where a fact could not be confirmed, the page says to ask the utility or the town.