Many devices including this one have what's known as a thermal cut out.
It is there for obvious safety reasons and prevents the temperature in
the locality of the cut out from exceeding a pre-defined value.
Some of them require you to press a reset button in order to switch the
power back on and other types simply reconnect the electricity supply
when the temperature returns to normal (safe) operating limits.
The Dyson DC07 has a thermal cut out located close to the motor and it is of the "self resetting" type.
If your vacuum cleaner switches off after a few minutes the most
probable cause (there can be others) is the thermal cut out has
operated.
The first and most important thing to do is to establish why it has
operated.... If the airflow around the motor has become restricted then
it will not be being sufficiently cooled and so it will have cut out
correctly. However, thermal cut outs are often quite crude internally
and it is not uncommon for them to start cutting out at too low a
temperature. So...
Here's what to do...
(some tools may be required to complete the following so read the entire
procedure before starting. Please note this is not an absolute guide if
you need really foolproof step by step instructions... buy a manual!
But this should help)
- remove and thoroughly empty the dust bin (do not put it back yet)
- remove and clean the drum filter to the right of the motor (right
when looking at the front of the machine). (N.B. Never put this back if
it is still damp)
- remove the accessories from the upright section
- withdraw the handle and separate it from the flexible hose (all
of these and the following parts have a colored (commonly yellow)
release tags/buttons/levers *** Never force anything!! ***
- remove the flexible hose
- remove the pipe union to the left of the motor
- carefully lie the machine on its front (wheels uppermost) and remove the u-bend
Check all these parts for blockages/clogging before continuing...
There are now only two areas left that I know of which may cause
further blockages. One is the "whole of life filter" located under the
dust bin and the other one is inside each of those seven little cones
(cyclonic chambers) at the top of the dust bin (root 8 cyclone is
usually written on one of them). The following will require some tools
and some common sense...
- carefully prise the plastic disc up (the one under where the dust
bin rests) use a flat bladed screwdriver or similar releasing it from
the lug you can see at the front. Inspect the filter and replace if
necessary (when replacing it you may find the original has been glued
to the plastic lid - if so gently scrape it off )
- If none of the above has revealed an obvious problem lets turn
our attention to these pesky little cones... if you have ever vacuumed
up any damp material these can become blocked. You will need a size 15
star drive (sometimes known as torx TX-15) screwdriver. I recommend you
buy one with a shaft length of at least 70mm (you will need one this
long if you are to access the thermal cut out later)
- Place the bin assembly on a suitable dust sheet.. this can get messy!
- remove the clear plastic outer bin
- undo the three star drive screws at the top and partly withdraw the top ***careful*** you can not fully withdraw this piece. All we are doing here is creating a bit of limited access and "peer room" (before withdrawing the lid you may wish to peer underneath and for future reference note how the release rod is engaged).
- now here you have to use a big dollop of care and common sense.
By peering into these cones (shine a powerful torch through the
sidewall of the cone) see if you can tell if any of them are blocked.
- using a small piece of wire or similar gently poke any blockages
away. Be careful not to damage the loose but still attached lid.
- reassembly is a bit tricky because you have to re-engage the
release rod at the bottom whilst at the same time pushing the lid back
into position. Take care not to damage or trap the large rubber sealing
ring as you press the lid home Finally replace the three screws being
careful not to over tighten.
If none of this revealed anything very positive... Its time to open up and inspect the motor casing/thermal cut out.
**** WARNING**** The next section requires someone who is technically
minded, has fiddly fingers patience and a basic understanding of
typical plastic goods assembly techniques. As I am not including
photo's the descriptions given can only be considered as pointers to
how to do it (I'm not writing a Haynes manual here! So if you are a cak
handed clot with little or no patience and a tendency to resort to ever
bigger hammers - take the vacuum cleaner to an independent repair shop
- explain the symptoms, tell them what you have done so far and leave it
to them!!
- In order to release the roller brush and belt mechanism turn the
vacuum cleaner face down undo the three 1/4 turn screws and carefully
withdraw the grey plastic cover (ease the belt guard section gently
away)
- coax the belt from the motor end then withdraw the belt and roller from its housing
- Now we need to release the mains cable from the switch area to the motor housing - Undo the screw below the yellow switch
- Working from the back prise the plastic housing forwards (this is
tricky) leaving the switch in the on position can help but the main
lugs stopping the housing from coming forwards are at the top just
behind the big yellow switch button. the best way is to insert a fairly
small flat bladed screwdriver in past the upper lugs at the back and
put a slight outwards force on the housing tou are trying to remove...
patience! Repeat for the other side
- Now undo the electrical connections and release the flex from its
channel so it is free to be withdrawn when you release the motor
housing
- turn the vacuum on to its front and remove the four torx drive
motor housing securing screws (two of these are down a fairly deep
recess)
- carefully withdraw the complete motor assembly from the shell
- The remaining part of the grey plastic casing can now be removed (a bit fiddly)
- You should now have the complete motor assembly housed in a black
plastic case with the grey intake at one end. Inspect this carefully
and you will see that the grey intake is held in place with four lugs.
gently prise the black plastic over these lugs and the grey intake will
come away
- Now you need to do two things in stages - pressing on the shiny
metal motor shaft will push the motor out of the black casing but make
sure that at the same time you feed the mains flex complete with rubber
boot through the hole.
- Voila the motor is now exposed
- Inspect the motor for any signs of overheating or damage - check
the brushes are OK (if you don't know what these are and you've got
this far, now may be the time to ask a friend with a bit more knowhow
to help!)
- Unplug the electrical connections and undo the small Phillips
screw holding the plastic assembly to the motor casing (this contains a
capacitor and firmly pressed against the metal motor casing is the
thermal cut out
- If all else seems OK replace the thermal cut out with a new one and reassemble
- No I'm not going to explain how to do that! For the most part
just carefully reverse these instructions! - come on you've made it
this far!!
NB. NEVER remove or bypass the cut out. this really could be very dangerous!
I hope this is of some help... Regards to all.
