Heating · Boilers & Hydronics · South Shore MA
Boiler Repair & Service
Half the homes on the South Shore run hot water heat, and a lot of those boilers are older than the people living with them. We repair cast iron and high-efficiency boilers on gas, oil and propane—and we know the difference between a boiler that has decades left in it and one that is done.
Relief valve discharging, or water pouring out of the boiler? Shut the boiler off at the emergency switch and close the cold water feed if you can reach it safely. A relief valve dumping means the system is over pressure or overheating—that is not a wait-until-Monday problem. Call (781) 974-5239.
What Your Symptom Usually Means
Boilers are honest machines. They tell you what is wrong if you know how to read them. Here is what we find behind the calls we take most, so you have some idea what you are dealing with before we arrive.
No heat anywhere
Failed circulator, dead aquastat, tripped high limit, bad thermocouple or igniter, or low system pressure. Most are same-day repairs with parts on the truck.
Some zones cold
Air trapped in the loop or a failed zone valve. Both are straightforward and inexpensive. If a zone has been cold for two winters, it is almost always one of these two things.
Banging or kettling
Scale build-up, low flow, or a waterlogged expansion tank. Worth addressing early—kettling is the boiler overheating locally, and it shortens the life of the heat exchanger.
Short cycling
Firing and shutting off every few minutes. Often a control or sensor issue, sometimes an oversized boiler fighting a small load. It burns fuel and wears parts fast.
Losing pressure
If you are refilling the system regularly, water is leaving somewhere. Chasing the leak matters—constant make-up water introduces fresh oxygen and rots a cast iron boiler from the inside.
No hot water, heat is fine
On an indirect tank, usually the tank circulator or its aquastat. On a tankless coil or combi, often scale restricting the domestic side. See water heater service.
When a Boiler Is Worth Saving
Cast iron boilers are the exception to most replace-it advice. A well-maintained cast iron unit can run thirty to fifty years, and the parts that fail on it—circulators, valves, controls, aquastats—are all replaceable at reasonable cost. We fix those and leave the boiler alone.
A cracked section is the end of the road. So is a heat exchanger leaking internally on a high-efficiency unit that is out of warranty—those repairs frequently cost more than a meaningful share of a new boiler. When we get there, we will tell you plainly and show you what we are looking at.
If replacement is the honest answer, see boiler installation—and ask us about Mass Save incentives and 0% HEAT Loan financing before you commit to anything.
Common Questions
What pressure should my boiler run at?
On a typical two-story home, roughly 12 to 18 psi cold, rising modestly when hot. Well below 12 and upper-floor zones stop heating. Climbing toward the relief valve setting means the expansion tank or the fill valve needs attention. Tell us what the gauge reads when you call—it helps.
Can I bleed my own radiators?
Yes, on standard fin-tube or cast iron radiators—open the bleeder slowly with a rag underneath until water runs steady, then close it and check system pressure afterward. If a zone still will not heat after bleeding, the problem is not air, and it is time to call.
Do you work on Navien and other combi units?
Yes. We are Navien Certified and service combi and condensing boilers regularly, including annual descaling and heat exchanger cleaning. Those units need real maintenance—skip it and you will be replacing components early.
How do I stop this happening again?
An annual cleaning and safety check in the fall. It catches the failing circulator, the waterlogged expansion tank and the drifting control before they leave you without heat in January—and it keeps your warranty intact.
Boiler acting up?
A real person answers our phone around the clock.