Grey Gritty Sludge Blocking Shower Filter

[keithmdw]

Hi Everyone

I had an issue recently where my shower slowed to a trickle (bar shower mixer fed by unvented cylinder for hot and mains for cold). Plumber replaced whole shower as when dismantled it was full of limescale and a grey sludge he said he’d never seen before.

New shower works great but every few showers it slows to a trickle again. I dismantle it myself and sure enough in the hot feed the filter on the cartridge is blocked with grey gritty sludge.

Could this be limescale coming from further down the system and what can I do about it as I can’t keep dismantling the shower every couple of days.

Thank you

 

[just pumps]

Next time you have to remove it hook up a hose and let water run out for 15 minutes then run some into a clear container and examine it.

 

[keithmdw]

Someone at work said it could be limescale from the hot water cylinder and maybe the system needed power flushing?

We had a faulty PRV on the HWC about 6 months ago and it had to be drained to be fixed. Could the refilling have dislodged crap from the tank I wondered.

By coincidence, we have a dodgy temp and pressure valve on the cylinder again and a gentle leak which British Gas are booked to repair in a week or two. The tank will need draining again though.

 

[Madrab]

Do you happen to have a megaflo unvented cylinder and does it look like this?

 

[keithmdw]

Certainly do

 

[Madrab]

@keithmdw have edited the post and added a pic

 

[keithmdw]

Thank you.

That is exactly what it looks like inside the cartridge filter

 

[Madrab]

Oh dear....you're not going to like the next bit .... How old is the cylinder and have you had it serviced regularly?

It is very possible and likely that the internal baffle inside the cylinder (the mechanism by how the cylinder creates it's expansion air bubble) is starting to break down. They have been known to do this and that pic is the very symptom/evidence that is shows when it's happening. Only fix is to replace the cylinder and they may do it under guarantee, hence the questions around how old and has it been serviced.

 

[keithmdw]

That doesn’t sound good at all.

On the plus side. We rent the property and the entire system is covered by British Gas care which the landlord pays for. So one way or another, apart from the hassle and disruption, the cost won’t be my problem.

no idea on age of cylinder. I think the entire system was new in 2006/2007 from something landlord said when we moved in.

Maybe that also accounts for the leaks on the cylinder which BG think are PRV.

Thank you for the quick and helpful responses.

 

[Madrab]

Yep, another symptom that is sometimes seen is the cylinders inability to retain it's expansion air bubble properly therefore it could suffer from increased pressure issues and the Temp and/or Pressure relief valve could be lifting as a consequence

 

[keithmdw]

Thank you. Will be calling British Gas on Monday and letting them know. They will still want to come out to assess it, but saves a wasted repair.

How can they tell that the tank is kaput? Is it an easy diagnose for them or subjective?

 

[Madrab]

They probably wouldn't know what it was unless that engineer had seen it before and confirmed it with Heatrae. Apparently it's the plastic baffle that sits inside the cylinder and holds the expansion air bubble that's breaking down.

No 2 in the diagram

Someone will need to call the and confirm but I don't believe it's repairable, it's a new cylinder time. Now whether it's a warranty call or not I guess sits with the landlord/BG

 

[Gasguru]

Do a search on the forum....there have been several posts (all within the last year) about the same problem and they were all due to the Megaflo baffles breaking up.

 

[fezster]

Does anyone know what causes the baffle to break down? Excess temperature? Hard water?

I've not experienced the debris myself, but I do have a Megaflo 250L and after a few years of use, the air bubble constantly required recharging every 3-6 months. I got fed up, so I had an engineer fit an external expansion vessel, which has been fine, but am wondering if and when I can expect the baffle to start breaking down like OPs.