Troubleshooting Shop-Vac Problems

Shop-Vacs are the ideal choice for wet and dry vacuuming in workspaces like your garage. They’re so popular that the term ‘Shop-Vac’ has become synonymous with these wet/dry vacuums, even when they’re produced by other brands.

Troubleshooting a Shop-Vac is straightforward. If it doesn’t turn on, check for incoming power from the socket and the circuit breaker. If it won’t start, the switch or motor is likely faulty. When dust leaks out where it shouldn’t, the cause is typically a damaged filter or hose. Lastly, weak or no suction is caused by dirty filters and full bins that must be cleaned.

Let’s take a closer look at common Shop-Vac problems and how you can fix them yourself.


When troubleshooting or repairing your Shop Vac, be sure to disconnect the unit from its power source. That will prevent the danger of electrocution and protect your fingers from being injured by moving parts.

Shop-Vac Won’t Turn On

A common problem that you might face with your Shop Vac is that you find you can’t turn the unit on. The most likely reason for this is that there is a problem with the incoming power.

To troubleshoot this problem, you must answer this question: “Is my Shop-Vac receiving any power, to begin with?”.

Answering that question will require you to inspect the following parts:

  • Household Power: Firstly, check that your household is receiving power from the local grid. You can do this by checking if your lights and other appliances are working in the same room, as well as in other parts around your home.
  • Circuit Breaker: Next, check the circuit breaker for the wall socket you’ve plugged your Shop Vac into. That breaker might have tripped, preventing the socket and your Shop Vac from receiving any power.
  • Wall Socket: Wall sockets can also be faulty, so check that the one you’re using is functional. You can do this by plugging another appliance, like a lamp, into the same socket.
  • Shop-Vac Power Cord And Plug: Lastly, inspect the Shop Vac’s power cord to ensure it is not torn or twisted. The plug on that cord must also be in good working order.

How To Fix It: The solution here will depend on the core problem. For instance, if your household isn’t receiving any power, you must contact your local power company. There’s a possibility that your area is experiencing a power outage that you might not be aware of at the time.

If the problem is a tripped breaker, check your household’s main electrical box. There, you can identify any tripped breakers and switch them back on.

A faulty wall socket, however, is a little bit more complicated. For the time being, you can use the Shop-Vac by plugging it into another working wall socket. After that, however, you will want to replace the faulty socket yourself or by calling a qualified electrician.

Lastly, a damaged power cord or plug must be replaced entirely. To keep your Shop-Vac safe to use, these kinds of electrical parts should be replaced with brand new items instead of trying to repair them yourself.

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Shop-Vac Won’t Start

Suppose you’ve confirmed that your Shop-Vac is indeed receiving incoming power, yet it won’t start. If that’s the case, then the two most likely reasons are:

  • The unit has a defective or dirty power switch.
  • The unit has a defective motor.

With a defective power switch, the incoming power will not flow to the motor when you turn it on. Therefore, the vacuum unit will not start.

On the other hand, a defective motor simply will not run even though it receives the power it needs.

How To Fix It: The affected part will need to be replaced if you have a defective switch or motor. Thankfully, both the motor and the switch are located within the motor housing.

Firstly, lift the top half of the Shop-Vac and place it in a suitable workspace. From there, all you have to do is unthread the few screws that hold the motor housing in place.

Before you go about replacing the switch, first check to see if there’s any dirt obstructing it. There’s a good chance that dirt might have gotten trapped around the switch contacts, preventing it from working correctly.

Once you’ve ruled that out, replacing the switch and even the motor is very straightforward. Simply disconnect the electrical connectors to either part and lift out the motor or switch. Then, put the replacement part in its place, and reconnect the wires the same way as before.

Image source: iFixit

Lastly, screw the cover back together again and use the Shop-Vac like normal.

Dust Is Coming Out From The Hose Or Exhaust

When a Shop Vac is in good working order, it will have no problems trapping wet and dry waste inside the bin (sometimes called the ‘tank assembly’). However, a tell-tale sign of a problem is when the dust comes out from the hose or exhaust.

If this happens, the problem is most likely in or around the filter or hose. To be precise, you might have:

  • The Dust is Too Fine: The filter you currently have on your Shop-Vac might not be enough for the type of dust that you’re trying to clean. For instance, exceptionally fine dust (i.e. smaller dust particles) will get through the filter instead of being trapped in it.
  • A Damaged Filter: After being used for a long time, filters can also suffer damage. For example, your Shop-Vac filter might have a hole in it that’s letting dust particles pass through and then leak out of the exhaust.
  • A Broken Filter Housing: Besides the filter, the filter housing that keeps it in place is also crucial. A broken housing will prevent the filter from being seated correctly, allowing dust to pass through the vacuum unit and out the exhaust.
  • A Damaged Hose: Hoses can also suffer damage. A tear or a hole in the hose could allow dust to escape instead of sending it straight into the tank.

How To Fix It: To fix this problem, first inspect your Shop-Vac hose, filter, and filter housing. It’s possible that the only solution needed is to clean your filter by shaking or blowing the excess dust off into a trash can.

However, if the filter or hose is damaged in any way, you will need to purchase a replacement. Although not ideal, a short term fix would be to duct-tape the damaged hose so you can continue to use it until you have the replacement.

Weak or No Suction

A Shop-Vac with weak suction can be very frustrating, and one without any suction at all is useless. If you’re facing this problem, there are three possible reasons:

  • Clogged Filter: Maximum suction from your Shop-Vac depends on the airflow inside. As the filter gets increasingly covered with dirt, the vacuum’s suction will become weaker. Eventually, there will be no suction at all because air fails to pass through the saturated filter.
  • Full Bin/Tank: The Shop-Vac bin or tank must also be emptied regularly. When it gets full, it will also jeopardize smooth airflow leading to weaker and weaker suction.
  • Suction Leak: A suction leak occurs when there’s a hole or tear, typically in the Shop-Vac’s hose. When that happens, the vacuum will suck in the air where it shouldn’t, and that will prevent it from focusing the suction where it’s needed at the end of the hose.

How To Fix It: Clogged filters and full bins are very straightforward to resolve. Firstly, clean the filters as best as you can. You can do this by shaking the filter into a trash can to remove the dirt or using compressed air to blow some of it off.

Image source: The Family Handyman

Remember: a Shop-Vac filter does not have to be perfectly spotless to restore suction. It simply needs to be clean enough to allow for air to pass through it smoothly.

As for the bin, you will need to empty it regularly. At best, you should empty it after each use. That way, you’ll never forget to do it, and you will enjoy maximum suction every time you use the Shop-Vac.

To fix suction leaks, first, locate the leak on the vacuum hose. Once you’ve confirmed that there is one, you will need to replace the vacuum hose entirely. You can cover the leak with duct tape, though that is only a short-term fix. 

Static Shock

When it comes to using a Shop-Vac, a common occurrence is when you receive static shocks from the unit. This issue can be very annoying, especially when you’re trying to get work done. However, you can rest assured that it is entirely harmless.

You get static shocks from your Shop-Vac because the air is dry in the space where you use it.

How To Fix It: Fixing this problem is quite straightforward if you own a humidifier. Simply turn the humidifier on in the workspace where you’ll be using the Shop-Vac. Alternatively, you could just wait it out. 

Again, it’s important to remember that static shocks are not dangerous to you or your equipment unless you’re working on small electronic equipment like computer or appliance motherboards.

Reader Comments (1)

  1. Don’t replace an enclosed switch just because there is dust around it. Check that the contacts open and close with an ohm meter. Don’t replace the motor before checking for open or shorted windings with an ohm meter. Check that the commutator brushes are not so worn where there is no carbon left. You may find that it would probably be more cost effective to buy a new vacuum than replace just the motor.

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