Brown marks on ceiling around DVS/HRV ducts

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nzben

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#305981 18-Jun-2023 15:37

Had a look at a property today, it was generally in need of some TLC but one thing that I noticed that I'm unsure of the cause is that there were brown patches around the DVS vents. My initial thought would be that it was from staining from smoke, but there is no fireplace and no evidence that the current tenants smoke.

My understanding of these systems are that they are pushing air into the house from the ceiling cavity, therefore the marks would be caused by particles in the air coming in - which is meant to be filtered.

Is it possible that this would be caused by a bad / clogged filter? Any idea what would cause this. The area of the stain / mark is probably about 10-20cm around the ducts, and it seemed to be around every duct in the house.

Thanks

Ben

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#3091493 18-Jun-2023 15:46

Just dust grab a cloth and it comes right off

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Jase2985

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#3091497 18-Jun-2023 15:53

the air gets statically charged in the fan and vents and the dust end up sticking to the roof round the vents, quick dust or wipe with a damp cloth gets if off pretty easily.

you will find its very fine dust that is smaller than the size the filter filters to.

timmmay

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#3091506 18-Jun-2023 16:20

The brown is from mouse farts.

tweake

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#3091518 18-Jun-2023 16:52

the other thing it might be, i've only only read of it not seen it, is that if the vent is not well sealed against the ceiling the air flowing over the edge of the vent causes air to be sucked through that gap. i would make sure the vents are not loose, otherwise a bit of sealant or foam gasket may be required.

personally i have not had that issue on mine and i'm not exactly clean.

scuwp

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#3091612 18-Jun-2023 17:00

Happens on ours from time to time. A quick zap with the end of the vacuum with the brush nozzle deals with it easy enough.

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thenine

37 posts

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#3092028 19-Jun-2023 15:12

the middle part should be screwed in. Loosen it so the gap is wider and that should help stop it happening in the future.

tweake

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#3092032 19-Jun-2023 15:15

thenine:

the middle part should be screwed in. Loosen it so the gap is wider and that should help stop it happening in the future.

the problem with doing that is most of them use that to control how much air flow goes into the room. opening it up will increase flow and reduce flow in the other rooms. you really need to have some gauges to test with to get the correct flow rates.

Silvrav

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#3092042 19-Jun-2023 15:44

Does it look dustlike? What I have seen on some, due to the extreme temp difference it can cause condensation, and causes stain marks around the vent.

Handsomedan

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#3092114 19-Jun-2023 17:11

Ours developed brownish "stains" around the vents after we had a particularly dusty bit of work done around the house.

Simply wiped it away after a quick vac to remove the initial dust.

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