Hello, first try cleaning the flame sensor, this is a small rod that ison the opposite side of the igniter, use some steel wool clean it and reinstall. Make sure you turn off power to furnace when cleaning. Also it could be that you furnace is shutting down on high limit due to the furnace overheating, this could be due to a dirty filter, dirty blower wheel, blower wheel not running up to speed due to a weak capcitor.
Should be an easy fix. Take the front panel off the furnace that accesses the valve, burner, etc.
Find your pilot assembly, this consists of the hot surface ignitor, (which glows bright when lighting) and the little rod next to it about around as a pencil lead. This is the sensor. Your sensor needs to be taken out and cleaned. One screw should hold it. It has one wire that leads to it. You may have to unplug the wire, be sure to notice where it goes before you unplug it.
The sensor can only be cleaned with very fine sandpaper or emery cloth. Do not get your fingers all over it or get it wet. After cleaning it put it back it in where it goes. Biggest chances are, your furnace will work fine! Hope this works. Stay warm.
1.
Thermostat calls for heat.
2.
Draft inducer motor starts.
3.
Pressure switch attached by a small plastic or rubber tube senses the
negative pressure produced by the draft inducer and
closes.
4.
Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a small
metal probe about 1/8" in diameter, with a white
porcelain base) does not sense the flame, so after 8
to 10 seconds the hissing sounds stops with no
ignition of gas to heat your home. Your furnace shuts down and goes into a lock out condition until you turn your power switch back
off and on again. Then the sequence starts all over
again with no ignition of the gas.
Solution:You probably need to
purchase and install a new ignitor. I would suggest that you inspect your
ignitor closely for cracks. Make sure you do not
touch the ignitor with your bare hands. If you do not
visually see a crack, then you could have a furnace control board problem or a
limit, rollout switch problem. The furnace's control board
might not be supplying the voltage to the ignitor. If your furnace
lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then
you need to clean your flame sensor with light sand paper or steel wool. You
might need a new flame sensor, but most of the time they can be cleaned an will
work well after cleaning.
129 views
Usually answered in minutes!
×