Tip & How-To about Heating & Cooling
Normal
0
MicrosoftInternetExplorer4
/* Style Definitions */
table.MsoNormalTable
{mso-style-name:"Table Normal";
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-parent:"";
mso-padding-alt:0in 5.4pt 0in 5.4pt;
mso-para-margin:0in;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:"Times New Roman";}
The gas furnace is on the blink and you need to figure out
what is the reason why the heater isn’t heating. Grab your electric meter,
preferably a digital one, and we’ll check out some of the possibilities.
In your gas furnace find out where the power enters. Check
the voltage between the black and the white wires. Make sure that the black
wire is the hot and the white the neutral. Reversing these wires can make
intermittent problems.
We have power to the unit, so let’s check further. If you
turn the power on and the purge blower and the main blower both start to run
then you probably have a high limit reset tripped. Look for the limit switch or
switches to reset them. A little snap when you push the red button on the back
will let you know that you found the right one. If there are no reset buttons
then check for continuity across the terminals. If the switch is open then you
need to replace it.
If your purge blower only runs but nothing else happens then
you have one of two other problems. Either the igniter is bad or the pressure
switch may be bad or the flue blocked.
Check the pressure switch first by seeing if you get voltage
across the terminals of the switch. If the switch is closed like it should be
with the vent fan running then you will not get a voltage across the terminals,
this is good. Go on to check for the presence of power going to the igniter.
Many gas furnaces have an igniter that is very fragile and
cracks easily. A small crack will keep the little bugger from getting hot and
being able to light your furnace. Pull the plug apart going to the igniter and
check for power. You may have to recycle the power if you have had it on for
any amount of time. Often the furnace brain will time out the igniter try for
ignition and will not have power to it continually. Also the power will only
stay on for a few seconds when it does try, so you need to be ready and watch
carefully.
If you are getting power to the igniter and it is not
heating up then you have a bad one. This often will only be visible by a fine
line of white dust on the surface of the igniter. This is the white line of
death for the igniter and indicates a crack in it. Purchase an igniter that is
compatible with your furnace or it may heat up too fast or not fast enough to
work with your model furnace.
Hopefully this gives a few more tips to help you trouble
shoot your gas furnace. As always, be very careful around and handling
electrical parts. I have been zapped a few more times than I care to remember!
Here is a tip that will help you try to figure out why your furnace is not working.
Basic Furnace or Heating System Troubleshooting
heatman101
981 views
Usually answered in minutes!
×