How to Replace a Gas Furnace Pressure Switch

What You'll Need
Jumper wire
New pressure switch

If you believe that your gas furnace is not functioning as it should be, then it could be the gas furnace pressure switch that is causing the problems. There are a few things you can check and steps to follow in order to ascertain whether this is the reason why the furnace is not working. It is in fact one of the simplest things you can do when replacing the switch.

Step 1 – Understanding the Problem

Gas furnaces can have many different types of pressure switches so it is worth knowing which one is in yours. The first type is one that takes into account the movement of air pressure in the fan of the furnace. This makes sure that there is a fresh air supply coming through regularly. In addition there is a water pressure switch that is used to for furnaces that heat water. If your gas furnace is not heating or it never shuts down, then you may have an issue with the switch. It may be broken or failing and will need replacing.

Step 2 – Examine the Switch

If you have a jumper wire handy then you can place this across all the wires that are leading into the switch. This can be done once the blower has begun. If this manages to light the burner and it remains lit, the switch is most probably the issue. It could be a blower that is broken, but is more likely to be the pressure switch that is faulty. The switch will be much easier to fix than the blower.

Step 3 – Replace the Switch

Once you have ascertained the problem and then checked the switch to make sure this is your problem, the next thing you need to do is to actually replace it. This is extremely simple to do. For the majority of gas furnaces the wiring will be low in voltage. This means that the chance of you being shocked is low. However, despite this, it’s still important that you turn off the power before undertaking this job. Check the screws in the box where the switch is located and get them out with the use of a screwdriver. Then you need to just move the two wires contained over to the new switch you are using and tighten the screws again so it is secure.

Step 4 – Turn the Power Back On

After you have completed these simple steps, the final thing you need to do is turn the power back on to your gas furnace. Once the power is on again you can test the device to ensure that it is not functioning correctly. Fire up the furnace in much the same way as before and check how it is operating. Bear in mind that it may take a little while for it to go through the process of lighting. However, hopefully now the switch has been changed, you should have a gas furnace that is fully functional again and heating your house correctly. So, it really is a very simple process that you need to go through to change a gas furnace pressure switch.