Recirculation extractor (cooker hood) not functioning correctly

by / Thursday, 20 November 2014 / Published in

HelloI have a brand new lamona extractor fan which is not ducted through the outside wall, it has the filters in that were recommended by Howdens but it doesn’t draw in any steam of the hob and instead just soaks my kitchen walls, cupboards, worktops the lot, can someone please tell me how to cure this without core drilling through the wall, starting to get on my nerves, Howdens have been no use at all, even after spending £10,000 with them, can someone please contact me 




Paul answers

Paul answers

Hi Allie
First I would like to say sorry to hear about the customer service at Howden’s they use to be a good company. If you have an extractor (cooker hood) that can be ducted to the outside I would thoroughly recommend doing it as you will save a fortune in filters that are really a waste of time as they don’t last long.
When the hood is used in recirculation mode, then the air is forced through a charcoal filter. This will reduce the airflow by up to 30% To start with!!.
The principle of a cooker hood is to suck the air from the hob then take it out of the room. When set on recirculation mode the air must go through the filters and then out through the top! back into the same room. If the air cannot flow through quickly enough all that will happen is the steam will get sucked up to the filter and then condense, which sounds like your problem. I would follow the flow and make sure it can go through the cooker hood quickly. Sometimes when fitted, people forget to take of the blanking plates off at the top (these are fitted for normal ducting). Or you have very bad blockage in the filters. Or if you are vent behind the cupboards something might be blocking the air flow. I would suggest reading the manual and checking the fitting.

Some useful info to know if you have the right hood.

To calculate the appropriate airflow level for your kitchen, you should multiply the volume of your kitchen by 10.

For example: If your kitchen is 3 metres wide, 5 metres long and 2.7 metres high, your calculation will be:
(3 x 5 x 2.7) x 10 = 405

This means that a hood with an extraction rate of 400 m3/h should achieve efficient ventilation of the room.

Most manufacturers, comply with the European standard IEC EN 61591. This means that the airflow is measured in a realistic scenario:

If a hood can only be used in re-circulation mode, then the airflow should be measured at the point of the metal grease filter with the charcoal filter in place (which reduces the airflow). This lower airflow figure is reported for  recirculation-only hoods.  Not all cooker hood brands use this accurate reporting method

One Response to “Recirculation extractor (cooker hood) not functioning correctly”

  1. Sinth says : Reply

    Hi I have the same problem, bought a new hood extractor for recirculatiion with filters. I have had a look online but can’t seem to find the answer of what to do exactly. I can’t have it ducted.
    Kitchen is soaking every time!!

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