We use different types of safety switches and gears at our home to make our home safe and deter some unwanted accidents. The furnace pressure switch is such a safety switch. You will find it near the motor; it works to shut or stop the furnace when detecting negative pressure.
Sometimes, you need to replace the switch or repair it if it gets damaged or stops working. You may find your furnace pressure switch is not working correctly. Today, I will show you the reasons and the solutions accordingly.
Why is my furnace pressure switch stuck open?
Your furnace pressure switch is stuck open because of the clogged hose or the disconnection. If you use the furnace pressure switch for a long time without maintenance, the hose might be clogged with debris. As a result, the switch will be stuck open, and you won’t get the safety.
Some other reasons are there why your furnace pressure switch is stuck open. Let’s explore them.
Venting Problem:
Sometimes, the gasoline or the motor fails to pass the inside gas or air through the pipe.
The main reason is that the pipe might be damaged or get too much dust. So, the ventilation becomes disrupted, which causes the furnace pressure switch to be stuck open.
Ventilation is a must for any motor or engine. If you look at the car engine, you will get the perfect example. You get the check engine light when the engine fails to pass the air. The same happens with the furnace pressure switch.
Broken Switch:
If your furnace pressure switch becomes too weak to work and is broken for some reason, it will be stuck open. It’s a typical case to get a broken furnace switch after a long time. Consequently, your furnace pressure switch is stuck open.
You have to replace the broken switch with the new one because repairing is not an ideal solution. And, you can’t expect to use the repaired pressure switch for a long time.
Clogged Hose:
The most culprit reason your furnace pressure switch is stuck open is the clogged hose. Sometimes, the hose is clogged due to the debris and dust inside the motor. In that case, it will fail to work correctly and create unusual pressure.
It’s ultimately stuck open the furnace pressure switch and doesn’t let it work properly. To avoid such an incident, you have to clean the motor once in a while.
Disconnected Hose:
Since the hose plays a crucial role in the furnace pressure switch, it needs to be connected. Otherwise, the furnace pressure switch can’t do anything. In a nutshell, the disconnected hose will keep the switch stuck open.
Blocked Drain:
Sometimes, the drainage system might get dust and debris, which is clogged for a long time. As a result, the motor will fail to pass the fuel and create internal issues. It will directly cause the furnace pressure switch to get stuck open.
Are furnace pressure switches normally open?
The furnace pressure switches are normally open. Manufacturers make this switch to remain open until it gets the negative pressure from the motor. As soon as the switch feels the negative pressure, it will be closed and stop the engine immediately.
Getting close is quick, and it will take a moment to be closed. Since it’s a safety switch, manufacturers create it with an automatic system. It has artificial intelligence to detect negative pressure. After that, it goes down and remains closed until you solve the problem.
Whenever you find your furnace pressure switch closed, check your motor carefully. There might be something that forces the furnace switch to shut down. First, disconnect the motor, and then check it properly.
What happens when a furnace pressure switch is stuck open?
When a furnace pressure switch is stuck open, it will not do the job that it’s supposed to do. We use the furnace pressure switch to shut down the furnace if it creates any negative pressure to avoid home accidents.
Sometimes, the clogged hose or the broken switch keeps the furnace pressure switch stuck open. Consequently, your safety switch will no longer do any task. It will fail to detect the negative pressure and remains open.
How to fix furnace pressure switch stuck open?
You can fix it since you get why the furnace pressure switch is stuck open. Still, I’m giving you some ways that you can follow to fix it quickly.
Check the Pressure Switch:
When you get the furnace pressure switch stuck open, you must check the switch first. Maybe the inside wires are disconnected and stop working, or the wires are burned. Anything can happen.
You have to check the pressure switch manually. If you find any mismatch, you should solve it. Connect all the wires if they are disconnected.
Reset the Control Unit:
After checking the switch, you need to reset the entire furnace control unit if you don’t find any issues there.
You find the circuit board or the electric board where all the head switches are placed. You need to reset the whole furnace control unit and fix it up.
Check the Ventilation:
If you still have the furnace pressure switch stuck open, you need to check the furnace motor. Maybe, the ventilation pipe is clogged and stops passing the hot air. You need to clean that and ensure secure ventilation.
Clean the Drain Line:
After checking the ventilation, you should also clean the drain line or the drain pipe. The drainpipe is often clogged with dust and debris that ultimately keeps the furnace pressure switch stuck open.
You have to clean the drain pipeline and then start the furnace intensely. This time, the problem should be fixed. If not yet, you have to go through the following steps.
Replace the Switch:
You check everything that causes the furnace pressure switch to get stuck open.
Still, you have this problem; you need to replace the pressure switch in this situation. Sometimes, the pressure switch stops working once it reaches the highest uses.
The new switch must sort out your problem. You might get the new pressure switch stuck open in the worst situation.
Call an Expert:
Last and the least is to call the HVAC expert. If you have tried everything I described above but still can’t fix the problem, you need to call an expert. He/she has professional experience and uses high-quality tools.
Therefore, the HVAC will be able to check the entire furnace and fix the furnace pressure switch stuck open problem.
How to open a stuck pressure switch on the furnace?
You can open a stuck pressure switch on the furnace by following the below steps.
Tap Gently:
If there is no significant reason behind the stuck pressure switch, you can gently tap the switch. It might be okay and come to the normal mode. That’s the first step; if you don’t get the result, you must follow the following steps.
Open the Switch & Find the Reason:
You need to open the switch from the furnace by unscrewing it. Remove the screws softly and keep them aside. Then, check the interior and find why the switch is stuck open.
You may find the wires are not connected anymore. If that’s the case, you have to connect the wires and replace some if needed.
Replace the Switch:
If the switch is still stuck open, you need to replace the switch. Maybe the switch is broken and can’t handle the pressure anymore. Therefore, replacing the lousy switch with the good one will be wise.
How much does it cost to replace a pressure switch on a furnace?
It costs around $250 to replace a pressure switch on a furnace inducing the labor cost. The switch price will be around $170-$180, whereas the labor cost will be $65-$70. You can save the labor cost if you know how to replace the pressure switch on a furnace.
But it’s safe to hire a professional HVAC and replace your pressure switch on a furnace. Don’t try to do it yourself since it might be dangerous if you don’t have previous experience.
However, the price of the switch will depend on the model and quality. The brand is also a deciding factor here. You have to make a flexible budget and then look for the best available pressure switch with the best quality.
Getting the best quality pressure switch will require a reasonable budget. Since it’s a safety concern, you should never go for the budget-friendly or cheap quality pressure switch. It might fail to respond in a complex situation.
Final Thoughts
The main reasons your furnace pressure switch is stuck open are the clogged hose, ventilation problem, clogged drain, and disconnected hose. You can solve the issues by following our tips. Every time you won’t be able to solve the problem, you have to hire the HVAC.