What people keep running into with furnace
Complaints tagged furnace, each raised by more than one person. One-off posts are not included.
16 recurring problems · 140 people · 12 forums we read
Raised more than once
Most people first.
- 48Water keeps getting in the house during heavy rainHeavy rain overwhelms existing doors, garage thresholds, and drains, allowing water to pool inside the living spaces and garage. This sudden flooding forces residents to constantly manage overflowing entry points and deal with moisture damage from structural vulnerabilities.
- 14Why is there water on the floor around my new water heater?Water on the floor around a new water heater can be caused by condensation, loose plumbing connections, or a leaking tank. Determining the source prevents unnecessary panic over a potential tank failure and helps you address simple connection fixes quickly.
- 13Why do cooling coils keep freezing over?Melting iced-over coils with a heat gun fails to fix the problem because they quickly refreeze even worse within a day. This leaves the unit struggling to reach its temperature set point, trapping owners with a system that won't stay cold and leaving them unsure where to go from there.
- 12Thermostat showing low voltage and no powerHVAC systems often lose power due to a blown low-voltage fuse on the control board or a tripped float switch in the condensate drain pan. When this safety switch cuts power to prevent flooding, the thermostat loses its connection and displays low voltage errors, leaving the heating or cooling system completely unresponsive.
- 8Why is my AC making a loud noise after changing thermostats?Replacing a thermostat can trigger a loud thumping or banging noise from the AC compressor right as it turns on. This unexpected compressor noise creates disruptive disturbances, particularly when the outdoor unit is positioned right outside a bedroom wall.
- 7Why is my furnace blowing cold air with a red blinking light?A furnace blowing cold air and flashing a red error code often indicates a tripped pressure switch or an issue with the inducer motor preventing ignition. This stops the unit from heating your home, leaving you with unheated air running continuously. Fortunately, some underlying causes like blocked tubing can be checked and fixed at home.
- 5How to light the pilot light on an old furnaceOld furnaces often have hidden pilot assemblies or switches that fail to ignite even when following standard steps like holding the gas switch and hitting the igniter. This leaves homeowners struggling to figure out whether the system requires manual lighting or if there is a deeper mechanical failure, often forcing them to call a technician.
- 5Why does my thermostat keep losing power and resetting?A short in the 24V circuit or a failing HVAC transformer often causes the furnace control board to lose power, which trips the 3-amp safety device and kills the thermostat. This leaves the system completely dead or causes smart thermostats like the Nest and Ecobee to repeatedly reboot during a call for heat.
- 5How to get a stuck blower wheel off a motor shaftA blower wheel that has spun and shifted on the motor shaft can become completely locked in place, resisting standard penetrating oil and heavy hammering. Because there is often no room for a standard puller and no spare parts available, trying to force it risks destroying the wheel hub or damaging the motor.
- 4Why does my air fryer heater keep clicking off?Heater relays can repeatedly click off and cut power during initial heating, requiring multiple power cycles or drawer openings before staying energized. This prevents appliances from functioning normally on the first try, forcing users to manually restart them several times just to get them to heat up.
- 4Furnace won't turn on after new AC installationThe gas valve may have been left closed or something was missed during the recent HVAC installation, preventing the furnace from starting up when the weather turns cold. Homeowners worry that waiting too long to report the issue will make the warranty company or contractor upset about the delay.
- 4Is a seasonal HVAC tune up actually worth the money?Professional seasonal HVAC maintenance often comes with steep costs like $900 to $1,100 for repairs, leaving people who are out of work wondering if they can just handle it themselves. Paying these high prices strains tight budgets, but skipping service altogether makes it difficult to know if the system will run safely and reliably.
- 4Why does a new furnace heat exchanger fail after 3 years?Restricted airflow and early rust can cause a heat exchanger to crack prematurely just three years after installation. This unexpected failure leaves homeowners questioning whether the part can be repaired or if it requires a full professional replacement.
- 3What size heat pump do I need for a waterfront cottage?Choosing the right heat pump size and brand for a waterfront property requires balancing reliability with unique conditions like high wind and intermittent use. Oversizing or undersizing units, such as putting an 18k head in a 500 square foot loft, complicates quick warm-ups and leaves owners stuck trying to compare brands like Trane, Carrier, Rheem, and Goodman.
- 2Furnace making a humming noise even when it is not runningA low-frequency hum or vibration coming from a furnace often traces back to an electrical issue or a stuck blower motor that is receiving power without spinning. While shutting off the furnace breaker stops the sound immediately, simply replacing components like the capacitor does not always resolve the underlying motor failure.
- 2Massive gaps around furnace filter and a pipe in the wayAir flows freely around massive gaps on both sides of the filter brackets, making it look like a botched upgrade missing protective foam. Attempting to replace the filter is often physically blocked by a black drainage pipe. Even after disconnecting the pipe's clamp, the leftover piece remains too long to clear the metal panel, trapping the filter inside.
Comes up alongside
Topics that keep appearing on the same problems — not topics with similar names.