What do I need to increase shower pressure?

[farticus]

Hi. I'm having the bathroom redone and want to install a better shower. We have a basic mixer one and the pressure is quite poor.

Our hot water is from a tank in the bathroom. I think it's a pressurised closed system. There is the main hot water tank with a backup immersion heater, and the boiler with a separate smaller tank labelled "expansion vessel" on the cold water feed. There is a pressure gauge that reads 2.2 bar, and a couple of valves we can open to top it up if the pressure falls.

Cold water is direct from the mains, the tank was removed.

If I'm understanding this right, I need something like a Trevi Boost, but those doesn't seem to be available when I search for them. Is it right that you can't control the temperature at the shower with those?

I see there are various other pumps available, but they seem to be designed for gravity fed systems. Can't have a power shower because they can't be connected to the mains. Is there anything else? Thanks.

 

[Madrab]

OK, there are 2 things here - A CH system that by the sounds of it is sealed (pressurised) and a Hot Water Cylinder that may or may not be unvented.

Can you take a couple of pics and upload them of the HW cylinder and area that has the expansion vessel and the gauge etc. What colour is the expansion vessel? Is there more than one?

 

[farticus]

As you can see, it's red.

Thanks for your help.

 

[Madrab]

OK, that's your central heating and the expansion vessel for it. The system pressure is quite high BTW. You really don't want it over 2 bar when it's hot, dropping to 1.5bar when cold (ignore that green segment on the gauge, it's misleading). So you (edit spell) either have it too high cold or the expansion vessel pre-charge needs checked if it goes that high hot.

As far as the Hot wat cylinder is concerned then it looks like it's open vented, so should have a cold water cistern in the attic feeding it? It certainly doesn't look like it's unvented as it would have it's own white/blue expansion vessel.

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Then the only realistic way to increase the shower pressure would be to pump it. You could use a Trevi boost but hear really mixed reviews about them, never fitted one mind you.

 

[MNW67]

Cold water is direct from the mains, the tank was removed.

Do you mean cold water to the shower is direct from the mains? Are you sure?

 

[Notch7]

I don’t know if these are a gimmick or actually work

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[farticus]

Thanks guys. Yes, I'm sure about the cold feed. We had a tank in the loft, but all sorts of issues with the boiler and vibration. Eventually they cut the tank out of the loop entirely, it's empty now. That was when they installed the pressure vessel.

It seems to work okay, we have hot water. The central heating pump runs all the time.

I'm not sure how to reduce the pressure. They just said top it up and keep it around 2.

About pumps. Where should the pump go? I've seen these ones which can go on the mains intake, should that increase pressure to the hot as well?

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[Notch7]

Do you mean cold water to the shower is direct from the mains? Are you sure?

I don’t see how that could be possible with that hot water cylinder

maybe op means the F/E tank was removed

separate smaller tank labelled "expansion vessel" on the cold water feed

Farticus, are you thinking that’s the cold water feed?

its not a feed, the cold water goes nowhere It’s just using the pressure for the expansion vessel,- as explained above


you must have a tank in the loft

 

[Notch7]

We had a tank in the loft, but all sorts of issues with the boiler and vibration. Eventually they cut the tank out of the loop entirely, it's empty now. That was when they installed the pressure vessel

But they do different things

that expansion vessel is for pressurised fully pumped heating…nothing to do with hot and cold water.

have you not got another tank in the loft - a bigger one?

if you could post a pic of the empty tank that would help

 

[MNW67]

I don’t see how that could be possible with that hot water cylinder

maybe op means the F/E tank was removed

I agree. OP definitely needs to check to see if there is still a cold water storage tank in the loft.

 

[MNW67]

Yes, I'm sure about the cold feed. We had a tank in the loft, but all sorts of issues with the boiler and vibration. Eventually they cut the tank out of the loop entirely, it's empty now.

There would have been two tanks in the loft originally. The smaller one would provide water to the central heating circuit. That one has been cut out of the system. But the larger one should still be there and in use. That larger one feeds the hot water cylinder and usually provides the cold water for the shower as well.

 

[farticus]

There would have been two tanks in the loft originally. The smaller one would provide water to the central heating circuit. That one has been cut out of the system. But the larger one should still be there and in use. That larger one feeds the hot water cylinder and usually provides the cold water for the shower as well.

Ah, okay. Unfortunately it is very difficult for me to access the tank in the loft, I'd have to get someone to do it. I guess they didn't explain it very well when they made the change. I've stuck my head up the ladder and seen a big tank, but that was all I could see. There might have been another one out of view.

The boiler needs a service, so I'll see if they can check the pressure and ask them about the tanks, but it probably won't be before I have the bathroom re-done as that is supposed to be starting in a couple of weeks.

In the photo of the expansion vessel you can see the disconnected pipe from the loft on the left hand side. There are three other pipes going up there, one hot and the other two cold. I don't know if that helps.

Anyway, it sounds like it is all gravity fed and I could just have a normal power shower.

 

[Fred Blogs]

I have one of these......... https://www.plumbworld.co.uk/mira-event-xs-thermostatic-191-32529 A tad expensive but it's a brilliant shower. Mine is an older model as I do not have an on off switch. Absolutely oddles of power from it. I have two cold water tanks in my loft though. They were there when we bought the house 3 years ago as was the shower. I'm told by a plumber that the second tank is to feed the shower although that is the only explanation I have had. As long as it works I don't care.

 

[MNW67]

In the photo of the expansion vessel you can see the disconnected pipe from the loft on the left hand side. There are three other pipes going up there, one hot and the other two cold. I don't know if that helps.

Does one of the pipes from the loft go into the bottom of the cylinder, probably on the left hand side?

 

[farticus]

All 4 pipes go to the loft.

1 - Hot, bottom of cylinder
2 - Cold, top of cylinder
3 - Cold, mains feed from bottom, pressure vessel and boiler via he flexible hose
4 - Disconnected

I'm fairly sure 3 is fed from the mains. There is a tap that I believe is the stop cock, but it's stuck so I can't confirm that. Will probably leave that to the plumber. I installed the Eddy descaler thing, it seems to have had an effect which confirms that is the cold feed.