Boilers
Boiler Repair in Union County & Central NJ
Gas and oil boiler diagnosis and repair for no heat, leaks, pressure issues, and unusual noises.
When the radiators go cold, the useful question is which part of the system stopped, and a boiler has several: the thermostat and controls, the ignition and burner, the circulator or zone valves on hot water systems, and the water-level safety on steam. We repair both steam and hot water boilers, from no-heat calls to leaks, pressure problems and noisy pipes. You can reach us any hour of any day, holidays included, and the technician traces the fault through the system before quoting, so you are not paying for parts that were never the problem.
Common problems and how we handle them
Why is my boiler running but some rooms are still cold?
On a hot water system, a room that stays cold while others heat usually points to air trapped in that radiator or baseboard loop, a zone valve that is not opening, or a circulator that has stopped moving water. Trapped air often announces itself with gurgling and a radiator that is warm at the bottom but cool at the top. On a steam system, a cold radiator is often a stuck air vent that will not let steam in, or a pipe that has sagged and holds water.
Why is water coming out of the boiler's relief valve?
On a hot water boiler, the relief valve opens when pressure climbs past its setting. The usual causes are a waterlogged expansion tank that no longer absorbs the expansion of heated water, or a fill valve that keeps feeding water into the system. Occasionally the relief valve itself is worn and weeps. The valve is protecting the boiler, so the aim is to find what is driving the pressure up, not to stop the valve from opening.
What causes banging in steam pipes?
Banging, often called water hammer, happens when steam meets water that has collected in a pipe and drives it against a fitting. Pipes that have lost their pitch back toward the boiler, a water level set too high, or dirty boiler water that surges are the common causes. On hot water systems, a rumbling or kettle-like sound from the boiler itself more often points to scale or poor flow through the heat exchanger.
My steam boiler shut off and the sight glass is low. Is that a problem?
The low-water cutoff did its job: it stops the burner when the water drops too low so the boiler is not fired dry. Water loss in a steam system has a cause, such as a leaking return line, a failed radiator vent letting steam escape, or a leak in the boiler itself. Adding cold water to a hot, low boiler can crack cast iron sections, so let it cool before refilling, and have the source of the loss found.
How the job works
- Ask what you have noticed, such as which rooms are cold, any new noises and when it started, then check that the thermostat is calling for heat.
- Confirm the burner receives that call and ignites, and read any fault codes or lockout lights on the boiler control.
- Check the pressure and temperature gauge on hot water systems, or the sight glass and low-water cutoff on steam, and look for leaks at the boiler and nearby piping.
- Test the circulator, zone valves or steam vents serving the zones that are not heating.
- Explain the cause and the repair options with a written price, and make the repair once you approve it.
- Run the system through a full heating cycle and confirm every zone or radiator heats before we leave.
Cost of boiler repair
On steam, most boiler repairs involve the air vents, the low-water cutoff or water feeder, or the near-boiler piping. On hot water, they more often involve the circulator, zone valves, expansion tank or fill valve. The costly exception on either is a leak in the boiler itself, a cracked section or heat exchanger, and on an older boiler that is when we price replacement alongside the repair. You hear what failed and get the price in writing before work begins.
Why homeowners call Vanguard for boiler repair
- Licensed and insured. We work under NJ Master Plumber license NJMPL 13344 and HVACR license 19HC00609600, and every job is done by our own technicians, never a subcontractor.
- Upfront pricing, free estimates on most jobs. You approve a written price before work begins. No surprise line items when the job is finished.
- 4.9 stars across 556+ Google reviews. Read what customers say.
- Answered 24/7. Our phone is answered around the clock, including holidays.
Related boiler services
Areas we serve
We provide boiler repair throughout Union, Middlesex, Somerset, and Essex counties, including:
Boiler Repair questions
Is it safe to keep running a boiler that is leaking?
A small drip from a valve or fitting can often wait for a scheduled repair, but watch the pressure gauge or sight glass, since the system is losing water. Water leaking from the boiler body or onto its electrical controls is more serious; turn the boiler off at its service switch and call us. If you smell gas, do not operate any switches at all. Get everyone outside first, then call your gas company or 911.
Can a cracked cast iron section be fixed?
Sometimes. Many cast iron boilers are built from separate sections joined together, and on some models a cracked section can be replaced with a new one from the manufacturer, as long as parts are still available. The boiler has to be drained, taken apart down to the cracked section and reassembled. On many residential boilers that amount of labor makes replacing the whole boiler the more practical choice. The technician tells you which applies after looking at the boiler and finding where the crack is.
My boiler pressure gauge keeps falling. Where is the water going?
Falling pressure on a hot water system means water is leaving somewhere. Look for drips at radiator valves, bleed screws, the relief valve discharge pipe and the boiler itself, keeping in mind that some leaks hide under floors. An automatic fill valve can quietly top the system up, which masks the leak while the fresh water brings in oxygen that corrodes the system over time.
What should I note at the boiler before calling about no heat?
On a hot water boiler, note the pressure gauge reading; on steam, note whether water shows in the sight glass. Look for a lockout light or a code on the boiler control. Note whether the whole house is cold or one zone, and which thermostat serves it. Confirm that thermostat is calling for heat and the boiler's emergency switch, often at the top of the basement stairs, is on. On an oil boiler, press the burner reset only once, since repeated resets can leave unburned oil in the chamber.
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