Black Deposits

[Brian1960]

Hi all, can anyone explain what the Black deposits could be that come out of the Hot water tap in the Bathroom, It also comes out of the Hot tap in the Bathroom basin.
We have an unvented water heater (15lt) which is not very old.
It supplies the Hot water to the Bath and Basin in the Bathroom.
It also supplies the Kitchen sink which shows no sign of any Black deposit.
The Black deposit is of a gritty feel to it.
At first I thought it was coming from the Heater but with it not showing in the Kitchen it sort of ruled that out.

Thanks in advance.

 

[Wayners]

Mould

 

[Brian1960]

Certainly not mould, it’s like a hard grit.

 

[Roddy Young]

When the diaphragm in the expansion vessel in our unvented sytem died, lots of black spots came through the hot taps. They were slimy, so maybe not the same as yours. We also noticed the water in the bath had a brown tint which was rust from inside the EV.

 

[Brian1960]

When the diaphragm in the expansion vessel in our unvented sytem died, lots of black spots came through the hot taps. They were slimy, so maybe not the same as yours. We also noticed the water in the bath had a brown tint which was rust from inside the EV.

What puzzles me is its not coming through the Hot tap on the kitchen sink.
Heater is less than 12 months old.

 

[mattylad]

Somewhere in that pipe run you have a rubber washer or similar that has perished, possibly in the tap if it's old.

 

[Brian1960]

Somewhere in that pipe run you have a rubber washer or similar that has perished, possibly in the tap if it's old.

Deposit feels like grit though, not rubber based.

 

[jj4091]

If it's less than 12 months old get the installer back to look at it. Presumably the old one never did that. Sounds like possibly ferrous oxide but you don't have any radiators to corrode.

 

[Stivino]

Do you know if there is manganese in your water supply?

 

[HERTS P&D]

Flexi tap connector breaking down?

Andy

 

[dilalio]

Flexi tap connector breaking down?

Andy

Beat me to it mate

 

[Brian1960]

Beat me to it mate

It's in the bath as well as the sink.

 

[dilalio]

It's in the bath as well as the sink.

Flexis on both?
Same age.
Has to be localised.
Remove any aerators and see what's behind them.

 

[Brian1960]

Flexis on both?
Same age.
Has to be localised.
Remove any aerators and see what's behind them.

Aerator on hot tap on the sink has a build up of the Black substance, it's not a rubbery texture though, flexi pipe on sink is not that old.
Really is a strange one this.

 

[dilalio]

Aerator on hot tap on the sink has a build up of the Black substance, it's not a rubbery texture though, flexi pipe on sink is not that old.
Really is a strange one this.

Leave aerators out and give the whole DHW pipework a good flush through... Any shower valve filters will need cleaning too.
Then see if it returns.
What UV cylinder?