What That Noise From Your Port Chester Heating System Means
Banging, hissing, clicking, whistling? Here's a homeowner's guide to diagnosing heating noises in Port Chester homes — and what's safe to ignore.
Published 2025-12-06 · Bravo Mechanical, Westchester County, NY
Port Chester (10573) homes range from 1900s wood-frame to mid-century brick to modern condos along the waterfront. Each has its own signature noises. Here's how to read them.
Banging and water hammer (steam boilers)
Cause: Trapped condensate slamming into incoming steam.
Why Port Chester: Many pre-1950 homes have radiators that have settled out of pitch. Condensate pools instead of draining back, then steam hammers it.
Fix: Shim radiator legs to restore pitch toward the inlet. Replace old air vents. If banging persists in the basement piping, near-boiler piping likely needs to be re-done.
Whistling or whooshing (forced air)
Cause: Restricted airflow — usually a clogged filter or closed registers.
Quick check: Replace filter, open all registers, listen again.
Persistent whistling: Undersized return ducts (extremely common in older Port Chester homes with flipped basements/finished living space).
Clicking before ignition (gas furnace)
Normal if it clicks 2–3 times then ignites. Problem if it clicks 5+ times then locks out — that's a failing igniter or flame sensor. Usually $150–$350 to fix.
Loud hum from outdoor unit (heat pump in winter)
Cause: Defrost cycle running.
Normal: Periodic 10-minute hum every 30–90 minutes when outdoor temps are 25–40°F.
Problem: Continuous hum + ice buildup means the defrost board has failed.
Vibration from boiler or air handler
Cause: Loose mounting hardware, failing blower bearings, or out-of-balance blower wheel.
Severity: Annoying now, expensive later. Bearings rarely last more than 6 months once they start humming.
Pop or boom on ignition
Cause: Delayed ignition — gas built up in the burn chamber before lighting.
Severity: Dangerous. Crack-the-heat-exchanger dangerous. Stop using the system and call for service.
Knocking from radiators (hot water systems)
Cause: Air trapped in the radiator or system.
Fix: Bleed the radiator using the bleeder valve at the top.
Hissing from a single radiator (steam)
Cause: Air valve doing its job (normal) — but should stop when steam reaches it.
Problem: Continuous loud hiss = stuck-open valve. $20 part, 5-minute fix.
When to call us immediately
- Gas smell + any noise
- Pop/boom on ignition
- Continuous outdoor unit hum with ice
- Vibration plus burning smell
24/7 Port Chester emergency service: (914) 318-7368 or book online.
Request service or a free written estimate or call (914) 361-9142. Serving all of Westchester County, NY.