Numatic WMD750 Extractor

[AndreB]

Good Afternoon,

Purchased one of these machines from Axminster via Ebay(Customer Return). Curious if anyone else has any experience with these extractors. It came with no documentation, so I've downloaded the NVD750 extractor(which seems to be identical other than the bag system) manual from the Axminster site, and I'm quite certain I've installed the filters, etc correctly. However, when I start it it sucks the bag up inside the machine and within short order, blows a hole in it. I've looked at some photos of the machine on the Internet and it looks as though it is may have a flap at the bottom which is pulled shut when the machine starts so as to not allow the bag to be sucked inside. I'm not certain of this though as the photos aren't terribly clear. In any case, my machine has no flap. If this is not the cause, then I suspect the bags as the ones which were provided with the machine are quite thin and flimsy(quite similar to the recycling bags provided by the council), and may not be up to the task. Maybe they chucked in a roll of bags which may have not necessarily been the correct ones when the packaged up the machine. I intend to get in contact with Axminster on Monday with these questions, but if anyone has any insight it would be most helpful and allow me to make a better informed query to Axminster in regards to this issue.

On a positive note, the machine is very easy to mount on the wall with a quick release bracket system which allows it to be very easily removed from the wall for cleaning,etc. It also seem to have a massive amount of suck until the bag pops. I haven't tried to reroute the exhaust yet, so the verdict is still out on noise levels.

Thanks,

Andre

 

[WellsWood]

Hi Andre

I got one of those cheap from Axminster too, earlier in the year. Fantastic machine, like you say loads of suck - so much so that on a couple of times when I've started it up without opening one of the blast gates it instantly collapsed the hose.
You're absolutely right, there IS supposed to be a flap over the hole at the bottom. The idea being that this flap is sucked up against the outlet sealing it while the machine is running. When the extractor is turned off and the vacuum dissipates the flap drops down allowing the collected waste to drop into the bag below.
The customer return items are notoriously lacking bits and bobs, but it's usually the accessories that go missing not parts that are bolted on (mine was missing part of the wall mount). If you can't get one as a spare from Axminster you may get more luck going direct to Numatic. Failing that it would not be very difficult to knock up something that would work just as well.
Let me know if I can help further - pictures of the missing part for example.

 

[AndreB]

Hi Mark,

Thank you, that is very helpful. I strongly suspected that there was some sort of flap system as the design didn't make a whole lot of sense otherwise. I assumed that there would be a few missing bits (Mine was missing the 32mm hose, and has one fairly minor dent) but at half price I didn't have a problem with it. I have now tried it with a circular piece of MDF blocking the hole at the bottom and it seems to work as intended, so I will definitely follow up with Axminster/Numatic tomorrow about the possibility of obtaining a flap assembly.

I've noticed that Axminster has listed another WMD750 on Ebay and this one seems to be missing both the flap and the bag cage, and possibly the wall mounting assembly, so maybe not such a good deal.

I'd be very interested in seeing any photos you may have of your dust extraction setup as I'm curious as to how you've plumbed in the extractor.

Thanks again,

Andre