Replace/clean rangehood carbon filters?

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MikeAqua

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#239612 26-Jul-2018 11:27

Our range-hood is getting bit sluggish. I've cleaned the primary screen, but the problem seems to be two disc shaped internal filters attached to the fan/motor unit.

These filters have charcoal gravel inside mesh panels. (similar in appearance to these https://www.appliance-smart.co.nz/ikon-ik-8999802-rangehood-filter?gclid=EAIaIQobChMIlcfdn7K73AIVBayWCh0hhgeVEAQYBSABEgJUIvD_BwE )

I've noticed that the mesh screens are getting clogged with lint. It's also possible the carbon is saturated. Can anyone tell me if it is possible to clean these filters - and if yes, how?

Our range-hood isn't the re-circulating kind. It vents to outside via about 4m of 150mm ducting. Would it be possible to remove the filters altogether?

Mike

gchiu

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#2062928 26-Jul-2018 12:15

I believe those filters are for using the rangehood in recirculating mode.

So, if you're venting outside, remove them.

This was the reason why our rangehood was sucking so poorly because the installer forgot to remove these filters on both ends of the fan unit.

MikeAqua

7773 posts

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#2062939 26-Jul-2018 12:38

gchiu:

I believe those filters are for using the rangehood in recirculating mode.

So, if you're venting outside, remove them.

This was the reason why our rangehood was sucking so poorly because the installer forgot to remove these filters on both ends of the fan unit.

I thought that too - but I'm hesitant in case they are there because the discharge duct is 4m long and grease/lint might accumulate within the duct?

It's in an apartment and the duct would be hard to get at (pull out all kitchen cabinetry hard).

Mike

gchiu

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#2062960 26-Jul-2018 13:43

If it's 4 m long then the air flow is already being compromised by those internal filters. And you're getting grease inside your kitchen as well.

But check the manual for your rangehood. It will likely tell you.

MikeAqua

7773 posts

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#2062968 26-Jul-2018 13:59

gchiu:

If it's 4 m long then the air flow is already being compromised by those internal filters. And you're getting grease inside your kitchen as well.

But check the manual for your rangehood. It will likely tell you.

No manual. No branding or model number. Probably bought as a job-lot when the apartment complex was built.

Definitely getting grease deposition inside the kitchen though.

Mike

gchiu

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#2062969 26-Jul-2018 14:04

Look carefully inside the rangehood for manufacturer's labels.

scuwp

3885 posts

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#2063018 26-Jul-2018 15:26

If it is externally vented...remove them. Other mesh filters come up good in a dishwasher.

Lazy is such an ugly word, I prefer to call it selective participation

MikeAqua

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#2064850 30-Jul-2018 10:34

After looking inside - no manufacturers name, but made in Italy and model is F19. A google search was not helpful.

Over the weekend I removed the carbon-filters and soaked and cleaned them with hot soapy water. They are currently drying.

The rangehood is now doing a much better job. I've also noticed that just after I turn the fan off I can distinctly a hear couple of plastic flaps closing. I've never heard that sound from it before, so it seems there is a significant increase in air flow.

I am still wondering whether or not it should have clean filters installed.

The range hood, bathroom and dryer all connect to the same discharge vent, so there would be some risk of grease build up along the ducting. Maybe that doesn't matter.

Mike

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gchiu

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#2064973 30-Jul-2018 14:11

That's probably the backdraft flap that you hear.

As for whether you need to reinstall the recirculating filters if you have managed to actually clean them and also managed to reactivate the charcoal, you could see how much grease builds up in the vent and decide then.

Active carbon filters are disposable items designed to remove grease and odours from cooking vapours before the air is channelled back into the kitchen. The active carbon filters must be replaced periodically to work properly, at least once every three months, depending on the frequency with which the rangehood is used.

...

Fully saturated carbon filters can become a barrier to air movement therefore limiting rangehood performance. In the event of fire, grease laden filters could be flammable and therefore regular replacement is recommended.

https://producthelp.fisherpaykel.com/nz/Cook/Rangehoods/Built-in_Integrated/HP90IDCHX2/User_Guide_HP90IDCHX2/05_Cleaning_and_maintenance

MikeAqua

7773 posts

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#2065012 30-Jul-2018 15:28

gchiu:

That's probably the backdraft flap that you hear.

As for whether you need to reinstall the recirculating filters if you have managed to actually clean them and also managed to reactivate the charcoal, you could see how much grease builds up in the vent and decide then.

Active carbon filters are disposable items designed to remove grease and odours from cooking vapours before the air is channelled back into the kitchen. The active carbon filters must be replaced periodically to work properly, at least once every three months, depending on the frequency with which the rangehood is used.

I've soaked and cleaned them with detergent until no more grease visibly came out and water stayed nice and clean/clear. There has been a substantial change in colour, weight (even wet) and feel and the hair-dryer is able to force more air through (very scientific test that last one).

I'm not sure whether the carbon has de-activated over time. There is no way for me to re-activate it.

3 months is a laugh. The apartment was built in 2010, and I'll bet they have never been replaced. I suspect the unit came with carbon-filters and a duct outlet so it could be installed as recirc or discharge and if a duct was connected the filters could be removed, but no-one ever did and no-one ever checked.

I think I'll reinstall them and see what happens. Test 1 - can I still hear the back-draft flaps. Test 2 - does the until pull all of the smoke out. If either test fails, I'll remove them.

The ducting is translucent and I can see it quite clearly from the manhole to check for grease build up.

Mike

gchiu

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#2065087 30-Jul-2018 16:42

How Is Activated Carbon Made? There are two different ways to make activated carbon but for this article we will provide you with the more efficient way that will create higher quality and purer activated carbon. Activated carbon is made by being placed in a tank without oxygen and subjecting it to extremely high temperatures, 600-900 degrees Celsius. Afterwards, the carbon is exposed to different chemicals, commonly argon and nitrogen, and again placed in a tank and superheated from 600-1200 degrees Celsius. The second time the carbon is placed in the heat tank, it is exposed to steam and oxygen. Through this process, a pore structure is created and the usable surface area of the carbon greatly increases.

So, unless you've managed to do all of that your carbon filters are spent. Putting them in an oven at 300 deg C doesn't remove the adsorbed chemicals either. You need to get new ones since you're intent on using your rangehood in recirculating mode.

MikeAqua

7773 posts

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#2065100 30-Jul-2018 17:08

gchiu:

You need to get new ones since you're intent on using your rangehood in recirculating mode.

Not intent, just going to have a try and see what happens. Only in the apartment for few more weeks. Then me move into another unit in the same building, which we have bought - with an identical rangehood .

Mike