Replacing Furnace Pressure Switches
Furnaces are one of the most important systems in a home. They keep us warm during winter and cool during summer. While it’s natural for some differences to occur in the temperature of different areas of a home, if you notice that certain rooms are colder than others, this could be a sign that your furnace isn’t working properly and needs to be repaired or replaced.
If you’re experiencing a heating system issue, it’s best to hire a professional contractor who can diagnose and repair the problem correctly. However, if the problem is something minor, you can take some minimal steps to troubleshoot your furnace repair and possibly restore it to its normal functionality without calling in a professional.
One of the most common issues with furnaces is that a pressure switch is stuck open, which means it’s not sending 24 volts across its terminals to close the gas valve when the inducer fan pushes air through the system. This happens when the hose that connects the pressure switch to the inducer is clogged with leaves, feathers, dirt, snow, or some other substance.
Luckily, if you’re able to remove the obstruction from the hose, this will probably fix the problem. If not, then it’s likely time to replace the pressure switch.
Repairing or Replacing Furnace Pressure Switches
First, you’ll need to shut off the gas and power to your furnace. Then, you can open the access panel to remove the old pressure switch. Once you have the replacement, be sure to follow the directions in the installation guide that came with your new pressure switch.
Before you install the new pressure switch, you should test for continuity on its two terminals using a multimeter. This should be done with the switch turned off and the hose removed. You should see a continuity reading of 0 or very close to 0. If the reading is higher than that, then your pressure switch has failed and must be replaced by a certified HVAC technician.
You can also use a multimeter to check the hose port that connects to the pressure switch for water. This can be a good way to confirm that the hose isn’t blocked by debris, and you can also check to see if the port is filled with water from condensation.
It’s important to remember that the parts for your furnace are specific to its brand, so be sure to find a supply house that carries the right parts for your particular unit before ordering replacements online. If you’re having trouble finding the correct part, you can always call your manufacturer to ask what they suggest. They’ll often have a list of recommended supplies on their website, as well. Be sure to include the part number of your old pressure switch and the model of your furnace when you contact the manufacturer’s support team. This will help them find the right part for you faster.
