Shower losing flow rate due to buildup on filter

[snowlucas]

Hi,

I have an upstairs shower (Aqualisa) which has been losing pressure or flow rate very quickly over the last few months.

Initially I thought this was limited to the shower and replaced the thermostat cartridge but after it happening again I've realised I keep getting a buildup of sugar sized white stuff on the shower filter (also appears on the tap filter in the same room). This substance seems to dissolve when I touch it and is easily cleaned from the filter. Initially after cleaning there was no improvement but after running the water for a while it gets back to and acceptable level. I assume this is due to air locks from having to turn the main supply off to clean the filter.

Annoyingly this seems to be happening in a fairly short period of time and the buildup comes back within weeks. The buildup only appears on the hot feed of the filter (they are separate) and the cold water pressure is always good.

The system is a Megaflow unvented cylinder and the only recent change (last 9 months) is the addition of solar diversion to the immersion heater. Previously the gas boiler handled all the hot water for the tank. Don't know if this is relevant.

I'd prefer to not have to clean the filter each week so does anyone have any idea what this buildup might be and how I mught prevent it.

Thanks

 

[ianmcd]

This has been covered a few times on here and it seems to be caused by the air gap membrane in the mega flow breaking down, if it is that then new cylinder time

 

[snowlucas]

Is there a way to confirm this. It’s not that old and the particles are easily dissolved. I would have thought the situation your describing would fill the filter with something that wouldn’t dissolve?

 

[snowlucas]

So filter cleaned last week and now looks like below. Even after cleaning the pressure is poor. Again the filter is easily cleaned and the debris has a sort of blue white colour.

I’ve tried to replenish the air gap in the mega flow again and got maybe a minute of gurgling. It’s on the bottom floor so I don’t really have a tap that’s lower than the tank (slightly lower than the relic valve though). Can I use another method to create the gap and is there a way to confirm it has worked?

Couple of other questions if someone would be kind enough.

Can I confirm the pressure coming off the tank in anyway?

Would it be normal for the shower downstairs to have decent pressure while the one upstairs has poor pressure if it was a megaflow problem? I assume the tank could have low enough pressure to cause issues on the first floor but high enough that the downstairs is fine.

Could low pressure cause a buildup of minerals on the shower filter as I’m seeing?

Thanks for any help. I don’t mind if it is the Megaflow (well obviously I’d be annoyed) that has failed I just want to be able to confirm it as the issue.

 

[Gasguru]

https://www.diynot.com/diy/threads/whats-on-my-filter.517984/

Pressure gauges plumbed in either side of the pressure reducing valve will tell you all you need to know.

You could try burning the substance or using acid on it to confirm whether it's scale or a plastic type material.

 

[snowlucas]

Very helpful thanks. I struggled to find those types of threads and that picture does seem similar to what I'm seeing unfortunately. I'm going to contact Megaflow and see what they think. The warranty situation confuses me. Its about 9 years old but installed by the previous owner. Anyway I will confrim the situation with them.

When I turn off the cold supply and run a hot tap it runs for less than 5 seconds (even after I try to replenish the air gap). Is this a sign that the air gap isnt being replenished as most descriptions expect the water to run for a period of time before you open the pressure relief valve?

 

[Gasguru]

The shorter the time the water runs the less the air gap.
You may need to drain the cylinder at floor level.

 

[snowlucas]

Ah thanks so I certainly don’t have good pressure and haven’t really replenished the air gap successfully. How do I drain at floor level? Megaflow don’t seem to show instructions if your unit in ground floor but surely it isn’t that much more complicated?

 

[snowlucas]

I’ve booked for a Megaflow engineer. £270 inc parts and labour if it can be fixed (which I’m assuming it won’t) or £90 inspection fee if it cannot be fixed. Warranty situation is very confusing as they say 25 years on the cylinder but we’re non committal on the membrane. Looks like others have successfully had the tank replaced and the call out fee repaid after the membrane was shown to be faulty so that’s where I think I’m heading.

I would still like advice on how to refill the air gap on the tank itself if anyone could help.

Thanks for the help so far.

 

[snowlucas]

 

[snowlucas]

So engineer visited and has confrimed the baffle is intact and isn't the issue. Said the tank was collecting a lot of limescale and she believed this is what I'm seeing on the shower filter. Suggested I might be able to get someone to remove the limescale from the tank and that I should use a water softener as this was a hard water area, south east water list it as moderately soft so this doesn't sound right to me, to stop this happening again.

So it seems my issue is some sort of limescale blockage on the hot water feed to the shower so I'm going to have to look into getting that fixed. I also need to get the tank empty of this limescale and look into softening the water. The only thing I can think of that may have caused the sudden change is the use of a solar diverter on the immersion which means it is being used regulally compared to previously where the hot water was from a gas boiler only.

Has anyone got any advice on removing the limescale from the tank or know anyone who will do it in the South East (Kent)?

Also interested in any advice around water softeners and if its a good idea to fit one? I'm getting some test strips to see whats really going on with the hardness.

Thanks

 

[dilalio]

So engineer visited and has confrimed the baffle is intact and isn't the issue.

How did she do this?
Does sound as though the immersion may have something to do with this... always consider recent changes to a system as a likely cause of new problems! Did the solar upgrade involve a new immersion heater or just how the existing one is powered? It would be worth draining the cylinder and removing the element... maybe this was furred up with "something" and is now dumping that into the tank through regular use, as you say... Chances are, it could eventually dissipate!?
Have you contacted the solar installers and asked if they've experienced this before, on previous conversions?
Might be worth fitting a strainer to the hot outlet of the cylinder!

 

[snowlucas]

How did she do this?
Does sound as though the immersion may have something to do with this... always consider recent changes to a system as a likely cause of new problems! Did the solar upgrade involve a new immersion heater or just how the existing one is powered? It would be worth draining the cylinder and removing the element... maybe this was furred up with "something" and is now dumping that into the tank through regular use, as you say... Chances are, it could eventually dissipate!?
Have you contacted the solar installers and asked if they've experienced this before, on previous conversions?
Might be worth fitting a strainer to the hot outlet of the cylinder!

She emptied the tank and I believe she said inspected the baffle through the PRV (which she then swapped as it was covered in limescale). I suspect the swaping of the PRV was more of a way to make the job chargable rather than an inspection but honestly at this stage my biggest concern is having to rip out tiles in the bathroom to replace pipework.

We dont really have issues elsewhere with limescale so potentialy a strainer might be a good solution over a softener, if I did it that way surely I'd need to have the tank cleaned of limescale on a fairly reguar basis? If I added a softner just for the tank I assume limescale in my hot water would never be an issue again?

 

[snowlucas]

I'm assuming limescale can build up in pipework and this could be the ultimate cause of my shower issues? What is the best way to confirm this and what is a normal way to fix such an issue? I'm going to ask a plumber to investigate and fix but it would be nice to know what to expect so I can avoid getting messed around.

Thanks for everyones help.

 

[Gasguru]

What does the "scale" do in vinegar or kettle descaler?