What people keep running into with furnace
Complaints tagged furnace, each raised by more than one person. One-off posts are not included.
7 recurring problems · 46 people · 12 forums we read
Raised more than once
Most people first.
- 22Water 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.
- 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.
- 7Thermostat 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.
- 3Why 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.
- 2How 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.
- 2Why 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.
- 2Furnace 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.
Comes up alongside
Topics that keep appearing on the same problems — not topics with similar names.