How to Test a Pellet Stove Vacuum Switch?

Are you worried about your pellet stove, which is not working? Are you worried because your pellet stove was new? Do you want to confirm that your pellet stove is permanently shut down or a temporary issue? We have covered you. By the end of this article, you will know how to test the pellet stove vacuum switch. Before diving directly to the test portion. We will let you know some basics like how it works? Why pellet stove ruined or shut down? Signs of bad vacuums, and how to fix common problems of pellet stove? How to Test a Pellet Stove Vacuum Switch?

Here’s How to Test a Pellet Stove Vacuum Switch Problems and Fix Them?

 You may face different problems with the pellet stove vacuum switch. Here I will explore some common issues and their solutions that may help you in some way. Also, the answer to the main question is How to Test a Pellet Stove Vacuum Switch? So, let’s start with the first and common problem.

Pellet Stove Not Turning ON

If the stove is not working or not starting then you may have a power bulging and not know this. Look at the stove or feed system, it may stumble. You may need to push the button to restore power. Another reason is maybe the fuse blew up.

Pellet Stove Starts but Shut Down Randomly

If when you start your pellet, it works well but after some time it shutdown slowly or abruptly. This is due to mechanical or sensor issues. If there are some mechanical or sensor issues, you can test them by seeing these three symptoms. If symptoms exist then the problem is mechanical.

  • The burn pot has some burned and some unburned pellets
  • After shutdown burn pot is empty
  • All the pellets are unburned

Pellet Stove Is Feeding Too Much Fuel

The most common reason for this problem is the dirty stove or vent. They are enough dirty to stop the flow through the stove fast, thats why fuel is running. If your stove is well cleaned then make sure

  • Your damper control is open
  • Burnpots are free
  • The firebox is airtight and does not leak from anywhere.

Pellet Stove Switch Will Not Shut Off

If the pellet stove is not shut off on its own, then shutting down be allowing it to keep running out of fuel, or just pulling the power cord are not only improper methods but dangerous also. You need to check whether the low limit switch is smashed, if so change it immediately.

Why Does the Pellet Stove Vacuum Switch Shut Down?

The safety system of a pellet stove uses a vacuum switch and a hose. The hose connects from the plenum to the negative port on the switch. Most of the pellet stoves use a negative port because the hose projected on the plenum is sucking air and compels the vacuum switch to close.
The positive part is where the air gust into the switch, and this positive pressure close the switch. If the exhaust blower shuts down, the switch stops the auger from turning as a pellet stove vacuum shuts down.

How Does the Pellet Stove Vacuum Switch Work?

The vacuum switch, also known as a safety switch, shuts down the pellet stove switch if the blower fails. When you Switch off your pellet stove, it takes 20 to 30 minutes to identify heat off. During this time, the power is sent to the exhaust blower to pull the air back. Once the air starts flowing through the stove, the vacuum switch senses the pressure and closes the circuit.

If the negative pressure of the switch is enough to close the switch normally, but if negative pressure drops below the safety range, the switch cause interrupts the power to the stove. If your pellet stove starts, stop suckle pellets after the cycle is over, then your vacuum switch is bad.

Signs of a Bad Vacuum Switch

Here we would like to highlight some signs, and if you see this on your vacuum switch, it means your vacuum switch shut down or at the edge of being destroyed.

  • Giving poor performance
  • Feel smelly
  • Poor performance
  • Produce smoke

What Can Happen With an Old Stove?

The hoses of the old stove get cracked or rigid, and some of the hoses get unbend from the point where they connect to the barb of the hose. The wire inside the stove may become weak or have a leakage somewhere. The hose and the vacuum bladder membrane connect to either plastic or metal. Different manufacturers of the furnace have other procedures to make their switches, hoses, and stoves. Some cost-saving engineers make the stove in this way that it creates more failures. New stove designs use a plastic vacuum that can carry a small voltage.

Test a Pellet Stove Vacuum Switch

Before testing the pellet stove, make sure taht the power of the vacuum switch shuts down and none of the parts of the switch touches the ground. Carefully insert the jumper in the switch and then plug the power back in. Do this step yourself if you are confident that you can do this. Otherwise, a trained engineer can assist you in doing this. After that, run the stove to see if the stove start working? If the furnace starts working, there is an issue with a vacuum. Then check the vacuum ports and hose if both are clean; there is an issue with the vacuum switch. An easy process for interim testing is the wire with a yellow arrow spike to the jumper wires inserted in the pellet stove connector.
This testing works fine if the stove is starting and working well with a tester or digital meter. If the stove begins to heat, then this part of testing may fail. Usually, a bad control panel can cause failures.


I hope you get everything about the pellet stove, and if found some typical problem, you’ll be able to solve it yourself. Otherwise, you can easily detect the issue and ask the engineer about a particular situation. If you have any questions, kindly ask below. Protection Status
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