Boiler Repair & Service in Baltimore, MD

Boiler Repair Across the Greater Baltimore Metro

Boilers are not furnaces, and they should not be serviced by someone who treats them as a variant. Hydronic systems have their own failure modes, their own safety considerations, and — importantly — a genuinely different repair-versus-replace calculation. A cast-iron boiler can be worth repairing well past the point where a forced-air furnace would be replaced.

Dundalk has the highest concentration of boiler-heated homes we serve, with more across Baltimore City, Catonsville, Essex, Pikesville, and the older parts of Glen Burnie and Ellicott City. We service gas, propane, and oil-fired boilers, hot water and steam. Request service.

Safety first, before anything else

If a carbon monoxide alarm sounds, or if people in the house have headaches, dizziness, or nausea that improve outdoors, leave and call 911 or the gas utility — not your HVAC contractor first. If you smell gas, leave before calling and do not operate switches inside. Boilers are combustion appliances and produce CO when venting is blocked, combustion air is inadequate, or the heat exchanger has failed.

Two hydronic-specific safety items: a pressure relief valve that is discharging is doing its job and signalling a real problem — do not cap or plug it. And a system with no water showing on the gauge should not be fired.

What the symptoms usually mean

No heat at all

Check the obvious: thermostat, the service switch (often at the top of the basement stairs), the breaker, and on oil systems the reset button — press it once. Repeated resets pump unburned oil into the chamber and turn a service call into a bigger job. Beyond that: ignition faults, a failed gas valve, a tripped low-water cutoff, or an aquastat problem.

Some radiators or baseboards heat, others do not

Usually air in the system, an unbalanced circuit, a stuck zone valve, or a failed circulator. On hot-water systems, bleeding trapped air often resolves it. On steam systems, this is more likely a venting or pitch issue and needs someone who understands steam specifically.

Pressure too high or too low

A hot-water system typically runs around 12–15 psi cold. Persistently low pressure means a leak somewhere; pressure climbing means an expansion tank that has lost its charge or a feed valve passing water. Neither should be topped up indefinitely without finding the cause.

Banging, knocking, or kettling

Banging in steam usually means water where steam should be — a pitch or venting problem. Kettling in hot water is scale on the heat exchanger causing localised boiling. Both are worth addressing rather than living with.

Visible water or corrosion around the boiler

Near-boiler piping, circulators, and fittings corrode over decades, particularly in the damp basements common near the water in Essex, Middle River, and Joppa. A weeping fitting is a repair; a leaking vessel is usually not.

What we do on a boiler call

We trace the actual circuit rather than assuming the original design is still in place — older Baltimore-area systems have frequently been modified repeatedly over the decades, and the drawing rarely matches reality. We check combustion and venting, inspect the vessel and near-boiler piping, test the safety chain including the pressure relief valve and low-water cutoff, verify expansion tank charge, and check circulator and zone valve operation.

You get the findings with photographs, and a flat-rate quote before work starts.

Repair or replace, honestly

This is where boilers genuinely differ. Cast-iron sectional boilers are robust and many are worth repairing at ages where a furnace would be replaced without discussion. Circulators, zone valves, expansion tanks, aquastats, and controls are all serviceable components, often several times over the life of a system.

What ends the conversation: a cracked or leaking heat exchanger or vessel, a failed safety chain that cannot be reliably restored, or a system that can no longer be brought into safe combustion. Our first job on any older boiler is determining which of those you have — a repairable boiler or a safety problem — because they are entirely different conversations. See boiler installation and replacement and the repair-or-replace framework.

Domestic hot water

Many boiler-heated homes produce domestic hot water from the boiler via a tankless coil or an indirect tank. If your hot water has changed at the same time as your heat, those are likely one problem rather than two. See water heater repair.

Related services

Boiler-heated homes have no ductwork for cooling — ductless mini-splits are usually the practical answer, and the boiler keeps doing the heating. Annual service matters more on oil and propane than on natural gas; see heating maintenance and tune-ups.