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Commercial Boiler Repair Across the NYC Metro
When a building loses heat, every hour counts for tenants, occupancy, and your liability. Com+ Mechanical repairs hydronic and steam boiler plants for property managers, owners, and facility teams across the five boroughs, Nassau, Westchester, northern NJ, and Stamford. We diagnose hard-down boilers, restore heat fast, and keep your plant compliant and running.
Common Commercial Boiler Failures We Repair
Boiler is locked out and won't fire
The flame safeguard (Honeywell, Fireye) has gone to hard lockout after failed ignition or flame-loss. Causes include a dirty flame rod, weak igniter, fouled gas valve, dropped gas pressure, or a draft/airflow fault. We read the control's fault code, prove ignition and flame signal, and clear the root cause rather than just resetting it.
Low-water cutoff keeps tripping the burner
A probe or float-type LWCO (McDonnell & Miller) is sensing low water and shutting the burner off for safety. On steam systems this usually points to bad water level control, a failing feed/condensate pump, or scale on the probe; on hydronic systems, a system leak or makeup-water fault. We find why water is low instead of bypassing the safety.
Building has no heat but the boiler is running
The boiler fires but heat never reaches the floors. On hydronic plants this is typically a dead circulator, a failed zone valve, or an air-bound loop; on steam, a waterlogged boiler, clogged returns, or failed steam traps starving the risers. We trace distribution to find the break in the loop.
Banging, knocking, or water hammer in steam pipes
Loud hammering on startup signals condensate trapped in the steam mains, sagging pipe pitch, flooded returns, or failed steam traps and a too-high water line. Beyond the noise complaints, water hammer physically damages piping and fittings. We correct water level, traps, and return flow to quiet and protect the system.
Boiler is leaking water or losing pressure
Visible leakage or a pressure gauge that keeps dropping points to a relief-valve discharge, a leaking section or push nipple, a failed gasket, or a corroded feedwater/backflow assembly. Constant auto-feed makeup water accelerates internal corrosion. We isolate the leak source and stop the make-up water cycle.
Burner short-cycles or won't hold temperature
The boiler rapidly fires and shuts off, or can't maintain setpoint. Common causes are a failing aquastat or operating control (Honeywell L404/L408), a bad pressuretrol on steam, scaled heat-transfer surfaces, or an oversized burner against low load. We verify the limit and operating controls and stage firing correctly.
No-Heat Boiler Repair for Commercial Buildings
A commercial boiler that won't fire, won't hold pressure, or keeps tripping on safety is not a residential furnace problem. It is a building-wide outage that affects every occupied floor. Com+ Mechanical services the full range of commercial heating plants common to NYC properties: cast-iron sectional and firetube hydronic boilers feeding fin-tube, radiant, and air-handler coils, and low-pressure steam boilers feeding one-pipe and two-pipe radiator systems in pre-war and mixed-use buildings. Our technicians work the actual failure: a tripped low-water cutoff, a locked-out flame safeguard, a failed circulator or condensate pump, a fouled gas valve, a cracked section, or a waterlogged steam system. We carry common controls and parts, isolate the fault on the first visit where possible, and get heat back to your tenants. For multi-building portfolios we coordinate across sites so one call covers the whole plant.
What Our Boiler Repair Service Covers
Why Property Teams Call Com+ Mechanical
Our Simple Process
From call to comfort in 4 easy steps
Dispatch & Triage
You call (332) 600-4640 and describe the symptom and building. We triage no-heat emergencies first and dispatch a technician to the boiler room with the controls and parts most likely needed for that fault.
Diagnose the Root Cause
On site, we read control fault codes, test the gas train, water level controls, circulators or condensate pumps, and combustion. We isolate the actual failure instead of resetting and walking away.
Repair & Restore Heat
We complete the repair — replacing the failed control, pump, valve, or seal — purge or refill the loop, prove safe ignition and flame, and confirm heat is reaching the occupied floors.
Verify, Document & Advise
We test safeties, check combustion and stack readings, and document what failed and why. If the plant is at end of life, you get a clear repair-vs-replace recommendation for budgeting.
Types of Systems We Install
Hydronic (Hot-Water) Boilers
Cast-iron sectional, firetube, and condensing hot-water boilers that circulate heated water to fin-tube baseboard, radiant loops, and air-handler coils throughout the building.
- •Circulator pumps, zone valves, and air-elimination
- •Aquastat / operating-control and limit repair
- •Expansion tank, feedwater, and backflow service
- •Condensing-unit and heat-exchanger diagnostics
Low-Pressure Steam Boilers
Steam plants common to NYC pre-war and mixed-use buildings, feeding one-pipe and two-pipe radiator systems where condensate returns to the boiler for reheating.
- •Pressuretrol and water-level control repair
- •Condensate and boiler-feed pump service
- •Steam-trap and return-line troubleshooting
- •Water-hammer and flooding correction
Boiler Controls & Safety Systems
The flame-safeguard, water-level, and combustion controls that govern safe firing across both steam and hydronic plants.
- •Flame safeguard (Honeywell, Fireye) diagnostics
- •Low-water cutoff (McDonnell & Miller) testing
- •Gas valve, igniter, and flame-rod replacement
- •Relief valve and high-limit verification
Why Com+ Mechanical
Commercial Heating Specialists
We work commercial boiler rooms every day — sectional cast-iron, firetube, and condensing hydronic units, plus low-pressure steam plants. Not residential furnaces scaled up.
Built for the NYC Metro
From pre-war steam risers in Manhattan to hydronic plants in Westchester and northern NJ, we know the building stock, the climate load, and the local code environment.
Safety and Compliance Focus
Low-water cutoffs, relief valves, and combustion are life-safety systems. We restore them to spec and keep your plant inspection-ready, not just running.
Portfolio-Ready Service
Managing multiple buildings? One relationship covers every boiler room, with consistent documentation and a single number to call when heat goes down.
Transparent Pricing
No fees. No surprises. Just honest service.
Boiler Repair Service
Full repair of the diagnosed fault — control, pump, valve, seal, or section work — to restore safe heat to the building.
- Repair or replacement of failed components
- Hydronic purge / steam level correction
- Ignition, flame, and safety verification
- Confirmation heat is reaching occupied floors
Preventive Maintenance Agreement
Scheduled boiler-room maintenance to reduce mid-winter failures and keep the plant efficient and inspection-ready across the heating season.
- Seasonal inspections and tune-ups
- LWCO, relief valve, and safety testing
- Combustion tuning and efficiency checks
- Priority response for agreement clients
Pricing is scoped after an on-site assessment of your boiler plant, the failure, and any parts required.
Own a Commercial Property?
Business+ plans start at $499/year — includes 2 rtu tune-ups, 10% off all services, and priority scheduling.
Equipment & Brands We Service
Factory-trained technicians for all major HVAC manufacturers
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Don't see your brand? We service all major manufacturers! Call us to confirm.
Proudly Serving Nassau County
Fast, reliable service in your neighborhood
Frequently Asked Questions
Get answers to common questions about our services
Do you offer 24/7 emergency boiler repair?
Yes. A no-heat boiler in an occupied commercial building is an emergency, and we dispatch around the clock through the heating season, including nights and weekends. Call (332) 600-4640 and we will triage your building immediately.
Do you service both steam and hydronic (hot water) boilers?
Yes. We repair low-pressure steam plants feeding one-pipe and two-pipe radiator systems common in NYC pre-war buildings, as well as hydronic hot-water boilers feeding fin-tube, radiant, and air-handler coils. Many of our buildings run one or both, and we work the whole plant.
Can you support a portfolio with multiple buildings?
Absolutely. Property managers and owners across the NYC metro use us as a single point of contact for every boiler room in their portfolio. You get consistent documentation per site and one number to call when any building loses heat.
My low-water cutoff keeps tripping — can you just bypass it?
No, and you should be wary of anyone who would. The low-water cutoff is a life-safety device that prevents a dry-fire and a potential boiler failure. We find why the water is low — a leak, a failing feed or condensate pump, or a scaled probe — and fix that cause so the boiler runs safely.
Should we repair the boiler or replace it?
That depends on the failure, the age and condition of the sections or heat exchanger, and the cost of the repair against a replacement. After diagnosis we give you a documented repair-vs-replace recommendation so you can make the capital decision with real numbers, not guesswork.
Can a boiler repair also improve efficiency and Local Law 97 standing?
Often, yes. A short-cycling burner, scaled heat-transfer surfaces, failed traps, or poor combustion all waste fuel and raise emissions. Correcting these during repair — and tuning combustion — lowers gas consumption, which directly helps a building's carbon intensity under Local Law 97. We can flag efficiency upgrades worth considering alongside the repair.
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Heat Down? Get a Commercial Boiler Tech Dispatched.
Don't leave tenants and occupied floors without heat. Com+ Mechanical repairs hydronic and steam boiler plants across the NYC metro, 24/7 through the heating season. Call now and we'll triage your building and get a technician to your boiler room.
Call (332) 600-4640