[Closed] Help - Waiting long time for shower to flow

it can take 15 minutes or more for flow to get going.

Any water to flow or hot water to flow?

It can be either I think. Sometimes nothing comes out, sometimes a dribble until it gets going. I think it can be warm before it fully gets going.

Would it be that during the day, using water on the other floors is actually emptying the pipes up to the second floor rather than taking water from the mains, so when you use the shower (2nd floor) it has refill the pipes first before the water comes out.

I'd try, get the shower running, switch off. then in turn open the taps / toilet downstairs one at a time - in between each try running the shower again and is there one tap that's more of a problem then the others.

Shower's above the hot water tank so a lot of effort's needed to get the water up hill. Not sure about pressurised systems but in old money it's negative head and you need to get a pump that switched into your shower on/off.

You have at least one problem there.
Sticking shower valve? so when you turn it on, it doesnt actually turn on. Happens with taps quite often.
Airlock somewhere in the pipes, though with a pressurised system, that isnt a prime reason for low flow, as the pressure will usually push the air out, though if there is a single pipe with an inverted U section, it may still be trapped air.
Pressure - your cylinder pressure should easily go above 1 bar, however, if the local water pressure is very low, you can only match what that is.
The boiler has nothing to do with the water pressure, it only heats up the water, nothing else.

More info needed. when you turn on the shower, and wait 15 mins, do any other taps on that floor work?
Do other taps in the house work?
If thelocal supply pressure is low, then the water at the top of the house may have more natural pressure than the incoming supply, so if you open a tap downstairs, the water may come, in part, from the upstairs pipework.
If there are any poor bits of pipework with unvented high spots, this could then lead to airlocks when you turn on the water upstairs.
I'd be finding out why the incoming pressure is low, that may be the cause of all your problems. Is you stop tap fully open? Have any pipes been damaged/kinked?

If the cistern is slow to fill, it's a problem with the cold supply, so it's not a problem with the boiler, although the boiler might be diagnostic, eg, if the boiler won't pressurise beyond 0.9bar it may be that the pressure of the supply at the boiler is only that. If that's the case, it won't push water more then 9m above that - but the pressure may fluctuate. Pressure meters that screw onto washing machine connectors are £10.

Are you sure that it's good pressure on the first floor, not just good flow? If the incoming pressure in your neighbourhood is low, it will drop in the morning when your neighbours are using their showers - assuming there are other houses nearby. If so, do others have problems?

Could be an issue with the cold water inlet composite valve which is on the cold feed to the unvented cylinder. The valve may also supply a balanced cold feed to all the cold water outlets in the house, except for one (usually the kitchen sink/sink closest to mains stop tap). The composite valve houses an inline strainer and pressure reducing valve; one of these being partially blocked/faulty could affect draw off pressure.

If you've got the same issue with both hot and cold on the en suite taps as well as the shower then it's not the shower.
I doubt it can be the boiler as it's a system boiler (which heats the tank) and not a Combi. There is hot water in the tank isn't there?
Your hot water is pushed around
byy incoming cold water.
I would be looking at either the house by the incoming flow and pressure - which are two different things.
The water company has a duty to supply a minimum water pressure, but poor flow can be caused by blocked or corrupted pipes.
We had good pressure but poor flow due to old galvanised pipe (coming from the meter in the verge) being corroded to the point that you couldn't see through a 2' section.
Replaced it with new pipe and flow is now great.

As other have said I’d want to know what the flow is like at the other taps in the house when this is happening.

I would want to measure flow rate and pressure as although they are linked they are very different. You can easily have high pressure and low flow.

And again I would be looking at the control group on the unvented, they incorporate a strainer, which could be blocked, a pressure reducing valve which could be broken, and a non return valve which can also get blocked by debris.

If it only affects the shower and wc, then the ball valve washer could either have become ‘lazy’ and remains mostly closed as that is how it spends most of its life or choked with debris again. The shower may have non return valves and strainers which could have become choked.

I’ve seen control groups on cylinders full of rust from galvanised mains, sand from ground workers pushing the pipe through a trench and handfuls of swarf from MDPE pipe.

If it is low flow but good pressure then I would recommend an accumulator, if both low pressure and flow, then an accumulator and charge pump.

Hi All,

Thanks for the tips and hints.

It affects supply to all water on that floor so I think it rules out the shower on it's own. I think if I turn a first or ground floor tap on while shower not running I can notice it's slower but it does flow.

There is a megaflow tank and it highlights operating pressure is 3bar - about 2 bar more than I am getting to it at the moment.

Sid

The control groups on Megaflows are the ones that I have had most trouble with.

It affects supply to all water on that floor

Then the fault very likely lies with the incoming mains supply.

If they’ve taken all the colds through the balanced port on the control group then I’d look at that.....

Solved! Everyone loves a good luck story!

Thanks all for the replies. With a combination of face timing my sparkie mate who dabbles in plumbing and him contacting his plumber we had zoned in on the pressure reducing valve [url= https://live.staticflickr.com/65535/50950432312_dd533ea17d.jp g" target="_blank">https://live.staticflickr.com/65535/50950432312_dd533ea17d.jp g"/> [/img][/url][url= https://flic.kr/p/2kCjhrw ]Untitled[/url] by [url= https://www.flickr.com/photos/97031505@N03/ ]Simon Darney[/url], on Flickr on the cold inlet. It contains a mesh filter which if partially blocked can prevent system pressure from being topped up.

I removed the plastic housing and started to clean the mesh filter[url= https://live.staticflickr.com/65535/50950432517_9a9f79629e.jp g" target="_blank">https://live.staticflickr.com/65535/50950432517_9a9f79629e.jp g"/> [/img][/url][url= https://flic.kr/p/2kCjhv4 ]Untitled[/url] by [url= https://www.flickr.com/photos/97031505@N03/ ]Simon Darney[/url], on Flickr and with a bit of jimmying managed to remove the cartridge as well. It dropped a shed load of debris, the spring [url= https://live.staticflickr.com/65535/50950336791_2bba50c69a.jp g" target="_blank">https://live.staticflickr.com/65535/50950336791_2bba50c69a.jp g"/> [/img][/url][url= https://flic.kr/p/2kCiN3B ]Untitled[/url] by [url= https://www.flickr.com/photos/97031505@N03/ ]Simon Darney[/url], on Flickr, on Flickr" alt="Spring" /> was completely worn in places and very mishapen and I couldn't even get it back on when I had finished cleaning to buy me some time. This meant a fun night with no running hot or cold water or toilets except cold tap in utility. We survived though!

At first I though I was going to have to install/have installed an updated version of the pressure reducing valve which due to being smaller would have meant some unwelcome pipework adjustments however, after a lot of to-ing and fro-ing I managed to confirm there was a replacement cartridge available and found one in stock 20 miles away! Refitted cartridge, got some silicone grease to help get housing back on and I was able to re-pressurise the system a treat (2.5 Bar); en-suite shower on top floor is like a bloody power shower now and toilet cisterns fill up in seconds!

Hopefully that might help someone in similar situation in the future!

Sid

That's excellent stuff.... Well done 👏
AFAIA those valves are generally not meant to be opened so it's not a surprise you couldn't get it back together.

I've got two megaflo cylinders though, so this is good info!

So the control group on a megaflo....

I've changed dozens of them, exactly like that, mesh filter blocks up, spring fails, new unit.

You are supposed to be able to clean them but that has never been very successful in my experience.

Good result.