What is it doing?
- is it "pulsing" that is turning on and off rapidly when the trigger is pulled? This is something designed into the cordless vacs so they don't destroy themselves trying to overcome a clog. Usually the vacuum will pulse for a few cycles and then shut down completely. you will have to wait for a short time before it will restart.
- Is it running for a while and then shutting off? This is much more common with the Dyson Corded vacs, but the cordless ones can do it as well. Again this is a feature to protect the motor of the vacuum from burning up.
- In both cases the issue is that the vacuum is heating up (triggering thermal protection in the motor) or the control circuitry of the vacuum (cordless models) is triggered by the behavior of the motor due to lack of airflow or a glitch in the system. Two main causes: Clogs and Dirty Filters. We will start by looking for clogs, but first we check battery and charging issues for cordless models.
The Battery Is Low
While this applies to cordless models only, it is important to fully charge the battery before doing all of the other troubleshooting steps.
- A low battery will cause the unit to shut itself off to prevent motor or battery damage.
- If the battery won't charge properly, you should replace it.
- Check to see if the unit still shuts off after charging or replacing the battery.
There Is a Charging Glitch
On some Dyson cordless vacs there can be a condition where the vacuum will run for about 10 seconds then shut off (no pulsing) One possible fix:
- Unplug the charger from the mains.
- Reconnect the charger to the mains
- Put your vacuum in the charger and hold the trigger for 15-20 seconds. Nothing will happen while the trigger is pulled
- Remove vac from charger and it should be normal
- For further info go to this answered question
The Vacuum Is Clogged
We will concentrate mainly on the cordless vacs here because they have this shutdown issue most frequently. For corded vacs, you should check out this page on clogs.
There are several common locations for Dyson cordless vacs to develop clogs. Just think "follow the air".
- The brush roll head is the first place to check. Dyson cordless brush rolls are quite simple to disassemble for cleaning.
- Since they have a one piece brushroll, it comes off from the end and allows easy access to the airway behind the roll.
- There is often some shrouding to remove, so be prepared to do a little disassembly if you can't see into the airway.
- There is a piece which can be removed to allow better access for clog removal in the airway, that needs only a coin to open.
- If you find a clog, remove it, reassemble the machine and test it. If no good, continue the checks.
- Next take a look at the wand and see if there are any clogs in it. Given that it is a straight pipe, the likelihood of a clog is low.
- The next step is to detach the wand from the vacuum body, and look at the opening where the air enters into the dust container. There is a deflector located there that can sometimes trap debris.
- You need to remove the dirt canister for best access for the next few steps..
- There is a latch that you must release apart from the latch which opens the dirt container.
- It can be tricky to remove the canister, and a slight rotation may help
- Check inside the center of the main cyclone for debris. It's a good idea to clean the filter screen at this point,
- Reassemble and test, if no good, go to the next item.
The Filters Are Dirty
Dyson vacuums rely on their filters heavily to trap both large particles at the first pass and very small particles downstream. The next step is to check all of the filters.
- We have already checked the filter screen in the cyclone and cleaned it (a major offender for lost suction).
- On cordless models there is a filter located in the middle of the cyclone portion which can frequently get dirty, and must be washed or replaced.
- When dirty, this filter can cause pulsing on cordless units. In some cases it may be simpler
- it can be washed by running water through it, but it helps to disassemble the filter before washing it.
- There is a plastic frame inside it that helps it keep its shape but also makes it harder to clean.
- To remove this, you have to carefully unlatch three clips at the top of the filter.
- When removed the filter can be more effectively squeezed, and gently wrung out
- Remember that any time you wash a filter, Dyson indicates that it should dry for at least 24 hours before being installed again.
- There is usually a motor post filter (often HEPA) that should be checked as well for dirt. On cordless models this often doubles as the endcap for the unit over the motor.
- Dyson has produced enough different models that it isn't possible to give detailed location information for each filter for such cleaning.
- Generally, the vacuums always have pre-filters before the motor that should be maintained regularly, except for the Cinetic models, which don't.
- All Dyson vacuums have a filter downstream of the motor. In some cases, like the Cinetic models, this filter will have to be reached by disassembly and is supposed to be a lifetime filter.
- If you have cleaned or replaced all of the filters, check to see if the vacuum operates normally. If so, you are done, If not go to the next step.
The Switch Has Failed
At this point, especially on cordless models it is a good idea to check the switch.
- Cordless models use a microswitch for the trigger switch, and if this fails or becomes intermittent, the vacuum will shut off unexpectedly.
- The microswitch completes a circuit which is sensed by a control board. The control board then sends power to the vacuum so it will operate.
- You can test the switch by disconnecting the battery, and disconnecting one lead of the switch from the unit and using a continuity tester. Since the switch is often prewired to the battery protection board, this may be difficult to do.
- If possible test the switch in place, rather than removing it from the vacuum. Some failures, especially intermittent ones, can best be found by wiggling things as they are in operating position.
- You may be able to test the switch by using something to hold the switch in the on position steadily.
- Watch to see if the vacuum shuts off when it isn't moved.
- If that happens it is less likely the switch, and more likely some thermal problem with the motor or control boards.
- If it doesn't shut off, charge it again, and check this by next trying the unit while shifting your grip on the switch; if the intermittent shutoff happens, you have found the problem.
- If the switch tests good go to the next step.
Control Board or Motor Has Failed
At this point, the causes are more catastrophic, the control board is not a readily available part and is relatively involved to replace. In many instances it can be purchased with the motor attached, as they often come as a unit. You can replace them together if all other issues have been checked.