Hi, I have the above mentioned vacuum cleaner for last two years. It keeps on switching off all of a sudden and doesn't turn on immediately. I have to wait about 20 minutes for it to start again. I have cleaned up all the filters and it still occurs. Any suggestions would be appreciated. Thanks
asked Oct 01 '11 at 11:07
When the Hoover WindTunnel, both bagged and bagless, including your Model U5780-900 run for a short time, turn off, then after 20 minutes can be turned back on, this is a very clear indicator that your Thermal Reset Switch Has Gone Bad, or there may be a clog in the machine somewhere, and the thermal reset switch is actually functioning the way it was designed.
What you'll need to do is first make sure that you are getting suction from the attachment hose. If you are, put the hose back into the vacuum, and recline the vacuum as if you were vacuuming the floors. Do you hear a noise change to a higher pitch sound when you are vacuuming the floors? If the noise is higher pitched, this indicates that you have a clog in the lower nozzle housing, usually this is right at the opening of the dirt port, where the dirt enters the vacuum. If a clog is the issue, what's happening is that because the motor can not get air sucked through it, it starts to heat up. Hoover installed a safety feature that will turn the machine off if the motor heats up, and won't allow it to be turned back on until it cools down. If you do have a clog, then you will notice there will be excess dust on the outside of the vacuum cleaner, this is a tell-tale sign of a clog. This could also mean that you need to clean / replace the filters, as well as the cyclone assembly. A Dirt filter that won't allow air to pass through can cause the motor thermal reset to trigger.
Try replacing the filter, Hoover WindTunnel Bagless Secondary Filter with Foam Filter Part 40110012, as well as the Hoover 40108212 Dirt Cup Lid and Filter Assembly to see if this fixes your problem.
If you have the same noise as when using the attachment hose, and there is no excess dust on the outside of the vacuum, then unfortunately this indicates that your thermal switch has gone bad, and is tricking the vacuum into thinking that your vacuum cleaner's motor is overheating, when in fact it isn't.
I don't recall the exact warranty on your particular model, but most models like these, including the U5781-900, UH70035, UH70085, and the UH70086 have only a one year warranty. It used to be that you could simply purchase the thermal reset switch, and replaced the defective one, however since Hoover was purchased by Dirt Devil, and has moved all production, and assembly to China, they no longer sell many parts separately, and now the only way to fix it is to buy the entire Motor, Thermal Reset Switch, Cord Reel, and Motor Housing Assembly complete, assembled and ready to go. For your U5780 the part number for this assembly is Hoover Part 21040104 Which retails for $109.99.
I hope this was helpful,
answered Oct 01 '11 at 12:04