Shut off the Gas Supply: Shut off the main gas supply to the furnace, keeping the pilot gas supply line open. light by holding it near the pilot flame jet's opening. Restore Power and Gas: After relighting the pilot light, turn the circuit breaker and the main gas supply back on.
There is a work-around to waiting. If there is no safety risk (like a gas leak), a furnace can be reset to bypass this wait. Turn off the furnace's power switch and wait 10 seconds before turning it back on.
Troubleshooting Weak Flames
Checking for any visible blockages, ensuring proper ventilation, and holding the equipment can help improve gas flow and subsequently strengthen the weak pilot flame. If these measures do not resolve the problem, contacting a professional technician from your gas company would be advisable.
Defective Igniter or Pilot Light
If it clicks but your furnace won't ignite after the combustion cycle, the electronic ignition systems probably need to be replaced. In cases where the furnace ignition starts normally but only stays on for a few minutes and then goes out, a new pilot light likely needs to be installed.
You can reset the ignition on your furnace simply. To do this you must cut the power to the furnace first by turning off the circuit that powers it. Once the power is off you can remove the burner door to reveal the ignitor. Turn this to “off” and leave it off for at least 5 minutes.
Most likely, your furnace is making a clicking noise and not providing heat because your furnace's spark igniter is trying to ignite your pilot light or burners but is failing to do so. In other words, there's an ignition system malfunction that needs to be fixed. Otherwise, your furnace won't start.
You may have an ignition system or fuel supply issue if your furnace doesn't produce heat after turning it on. You can check if you have fuel issues through the following steps: Look at the gas supply line to make sure the gas valve is open. Make sure that your tank has enough fuel if you use oil or liquid propane.
Attach one wire from your multimeter to the flame sensor wire and the other one to the unit where you unplugged the wire. Turn on the unit. Look for a reading between . 5 and 10 micro-amps with the normal range between 2 and 6.
Checking your thermostat is the best place to start. Make sure it's set to “heat” and that you've set the temperature higher than the current room temperature. If that doesn't resolve the problem, try switching your fan to “on” to force the furnace to start working.
The flames from the burners may be going out because they're struggling to draw enough oxygen for combustion through excess dirt or other grime along their surface. This is often a problem in a furnace that hasn't received regular maintenance.
If a furnace isn't receiving enough airflow, it may overheat and trigger the reset button to trip. Make sure to clean or replace the air filters and keep the air vents open enough for proper airflow. Occasionally, the flame sensor rod may be coated with dirt and debris, causing the furnace to shut off.
If nothing's happening when you're expecting the whir of a blower, check the circuit breaker and fuse. At your electrical panel, make sure all switches related to the HVAC system are on. Reset any tripped breakers and replace all blown fuses, and your furnace should kick back on.
Turn the gas control valve off and let the gas dissipate for five minutes before turning it back on in order to prevent a fire hazard. Turn the gas back on quickly, not letting it build up for longer than a couple of moments. If you get interrupted, turn the gas off again and repeat the process.
If your furnace won't ignite, the source of the issue may be a broken flame sensor. The sensor is responsible for turning off the gas burners to avoid gas buildup. Once this component starts to malfunction, it may stop the burners from igniting altogether.
The first thing to check is your thermostat. It might be clicking yet failing to trigger the heating. Ensure it's set to 'heat' mode and the temperature is above the current room temperature. Incorrect settings or a malfunctioning thermostat can be a primary reason for the furnace clicking but not turning on.
There are several reasons why your furnace may not turn on. The most common include a broken thermostat, gas line issues, clogged air filters, blocked ductwork, a tripped circuit breaker, and issues with the furnace itself.
Short cycling is a common sign of a bad flame sensor. The sensor thinks that there isn't a flame, so it shuts off the gas as a safety mechanism. Except, there is a flame and without the gas to supply it, it dies. This is a frustrating problem, but an HVAC technician can fix it.
If your furnace's problems continue, contact an HVAC expert. Also, if you notice discoloration when you check the pilot light, get professional help. If there are cold spots in your home, even though hot air is coming out of the air vents, the issue could be different from your furnace not working.