- 98 Morris Turnpike, Newton, NJ 07860
- constantservice3@yahoo.com
- (973) 948-0680
FURNACE PROBLEM · DIAGNOSIS GUIDE
If your furnace keeps starting and stopping every few minutes, you've got a short-cycle problem. Here's what's causing it.
Short-cycling damages the heat exchanger over time. A cracked heat exchanger means full furnace replacement — not repair. Catching short-cycling early usually means a $150-$300 fix instead of a $5,000 replacement.
Short-cycling is when a furnace turns on, runs briefly (often 1-3 minutes), shuts off, then restarts after a short pause. The system never runs long enough to actually heat your home efficiently, energy bills creep up, and components wear out faster.
Modern high-efficiency furnaces have controls that intentionally prevent short-cycling. When they short-cycle anyway, something is wrong.
If your furnace is too big for your home (an installer's sizing mistake), it heats up the space too fast and shuts off. This is more common than you'd think — when in doubt, installers used to oversize. Replacement to a properly-sized unit is the only real fix.
Restricted airflow makes the heat exchanger overheat and trigger the high-limit safety switch, which shuts the furnace down. Replace the filter and see if that fixes it.
The flame sensor verifies the burner ignited successfully. A dirty or failing sensor reads no flame and shuts the gas off. Cleaning or replacement: $150-$300.
Erratic signals from a failing thermostat or a wiring issue can trigger short-cycling. We test wiring and thermostat function on every call.
Closed registers, blocked returns, or undersized ductwork can cause the heat exchanger to overheat and trip the limit switch.
Replace the filter first. If short-cycling continues, call us — short-cycling damages the heat exchanger over time, and a cracked heat exchanger means full replacement.
“Furnace was kicking on and off every two minutes. Turned out my filter was destroyed. They checked everything else for free anyway. Honest crew.”
Tom B. · Mendham, NJ
Same-day appointments in Sussex and Morris counties. 24/7 emergency dispatch — answered around the clock by a real on-call technician.
98 Morris Turnpike, Newton NJ · NJ HVACR Lic #19HC00108700 · Since 1999
At Constant Air, we specialize in delivering high-quality heating, ventilation, and air conditioning services that keep your home and business comfortable all year round.
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