Extractor ducting size - help please

Discussion in 'Kitchen Fitters' Talk' started by Rob H, Jun 20, 2018.

  1. Kat_H

    Kat_H New Member

    Hi Rob,
    Can I ask what happened with your extractor since. Im in the same predicament after my builder fitting 100mm x 60mm ducting under concrete but the length is about 3meters long. The manual which i sent him had a accessories with minimal width 150mm for an Elica nicolatesla prime hob/downdraft extractor and am concerned about its performance/noise level now
     
  2. gas monkey

    gas monkey Well-Known Member

    good moning mr r just being intrested what pressure regs are you saying abooout
     
  3. kitfit1

    kitfit1 Screwfix Select

    So, yet another builder penny pinching because "i know better than the manufacturer".
    The correct size ducting for your hood is 222mm x 89mm. Considering you will have laid out between £1400 and £1700 for the hob/extractor, i would force the builder to dig the trunking out and lay the correct size.
     
  4. Kat_H

    Kat_H New Member

    :(He had to dig it out already before laying it as they didnt consult me on my kitchen plan before laying foundations. The floor is down and kitchen being assembled today :((
     
  5. kitfit1

    kitfit1 Screwfix Select

    As a kitchen fitter i can tell you the following will be the result of fitting the wrong size ducting:
    1: the hood will be considerably louder than it should be.
    2: the hoods ability to move as much air as was it designed to move will be halved at least. If Elica assume a maximum ducting distance of 3m, then your hood will actually extract nothing.
    3: the warranty on the hood will be voided the moment you first use it, because it hasn't been fitted as per the manufacturers instructions.

    If you are prepared to accept what will happen, then go ahead and fit the kitchen.
    Floor laid or not laid, my advice remains the same. Force the builder to dig it up and replace the ducting with the correct size, at their own cost.
    Some have mentioned earlier in this thread about installing an in-line extractor to help. This is actually a complete red herring because the trunking under your floor is rectangular.....................there is no such thing as a rectangular in-line extractor.
     
  6. Pollowick

    Pollowick Screwfix Select

    Domus is actually 220x90 - not much difference though.
     
  7. kitfit1

    kitfit1 Screwfix Select

    222x89 is the size in the PDF for that hood.
     
  8. Kat_H

    Kat_H New Member

    Those are there for the ducting from the hob to ground level. The manual does say further duct at 150mm
     
  9. Pollowick

    Pollowick Screwfix Select

    150/6" circular has an internal CSA of approx 17500 sq mm

    220x90 is 18900
    222x89 is 18800

    All are considered similar and if teh manual suggests 150mm then using 220x90 or similar should be fine, but no smaller.

    Whereas the 100x60 you have is 5500 which is even worse than 4"/100mm with a CSA of 8000.
     
    kitfit1 likes this.
  10. kitfit1

    kitfit1 Screwfix Select

    Lol, was just about to post much the same thing Pollowick :D

    It can be confusing for peeps to work out what they need because the hood manufacturers always go by the circular size, which is of course 150mm.
    The reality is though though Kat_H needs this:https://www.i-sells.co.uk/system-220x90-flat-channel-1m?ref=prodDesc

    Which goes back to what i posted earlier, the ducting he has might as well not be there because it will never work.
     
  11. Mr Rusty

    Mr Rusty Screwfix Select

  12. Kat_H

    Kat_H New Member

    :[ The island isn't fixed to floor so can be moved to dig the floor up but im 100% sure Ill have a fight on my hands for it to be done. But no point in rolling over to have a useless extractor after all I did to afford it
     
  13. kitfit1

    kitfit1 Screwfix Select

    Have you paid the builder all the money yet ? if not, then tell the builder in no uncertain terms they are not getting another penny until the ducting is sorted as to the manufactures instructions. As you said, this hob/extractor has cost you an arm and a leg.......................don't give the builder your kidney as well.
    If peeps like yourself actually stand up to stupid builders that think they know better, then things like this will happen less often.
     
  14. Kat_H

    Kat_H New Member

    No, we havn't given him the final payment yet so will be holding tough on that as leverage. He claims he phoned the distributor for advice but I recall him saying he couldn't get onto them and that's why I found the manual and sent him it so will call the distributor in the morning to confirm what they advise before I throw down my glove.
     
  15. Joey__

    Joey__ Member

    It's your own fault so don't blame the builder he has just done what you asked him to do. Would you ask a joiner to change your lights?
     
  16. Joey__

    Joey__ Member

    The builder has done what he was asked to do so don't slate him he builder when it's the clients own fault
     
  17. kitfit1

    kitfit1 Screwfix Select

    The builder has not done what he was asked to do. The builder was sent the manual for the hood, which clearly states the ducting size to be used. But instead installed 100mm ducting which has a capacity 75% less than that of the correct ducting.
    Maybe read the thread before blaming the client :rolleyes:
     
  18. Pollowick

    Pollowick Screwfix Select

    Will the 100mm be big enough for the builder to bury the troll in?
     
  19. kitfit1

    kitfit1 Screwfix Select

    Are you referring to @Joey__ ?
     
  20. Pollowick

    Pollowick Screwfix Select

    I may well be especially as the mods seem to let him stay - giving bad and dangerous advise, trolling and digging up old threads.
     
    Timbo66 likes this.

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