Not happy with with new unvented system, although it works fine. Shower pressure issue

[kash]

Old setup.
Vented system - indirect
x2 Cold water tank in the loft. x2 80L Hot water tanks, regular boiler and stuart turner 4bar twin shower pump for the master bedroom shower. Worked pretty good, although the tanks were manky and old. The shower though was epic and used to blast water out. The house was gutted for refurbishment so plumber advised to change the set up for a new unvented system, that would deliver mains water pressure throughout the house. which it does.

New set up
Kingspan 300L horizontal tank. No shower pump and just the regular boiler. It’s all installed correctly, signed off and actually works quite well. All the taps and showers get mains water pressure.

Problem
I got too used to the shower pump pressure. The showerhead we have is an XL rainwater shower head and used to love the water blasting out. Whilst the showers still ok, it's just ok and not amazing anymore. If the shower in the family bathroom is run, there's a slight drop in pressure which i was expecting, but this makes the shower experience even less enjoyable.

Is there a solution?
We can’t install the same shower pump on the mains as it would draw too much water from the rest of the house and stop the other taps working - and probably mess with neighbours too. Assume this would also stop things like toilets refilling and draw air once water supply is exhausted.

So my questions are..... What is the solution for me to have a dedicated water supply for the shower again, so that I can use the pump?
Can I install a smaller vented system in addition to the unvented system that I have? The plumbers going to have a think on the best way of achieving this and let me know a price, but thought I’d ask on here too.

I know it’s potentially an expensive addition... but it just depends on cost. The shower is absolutely ok as it is, but i know how good it was and just wanted to make it awesome again.

Are there any other solutions that can be used with the new unvented tank I have?

 

[steadyon]

If you have the space, you could consider installing an accumulator.

 

[EvilDrPorkChop]

Is the main adequately sized to the Unvented, do you know what your water pressure? An Unvented will only be as good as your incoming supply and pipe sizes for pressure and flow rates. Do you know what pipe sizes are to your shower valve?

If all of the above are OK and correct then you could go down the route of an accumulator, however this is like the size of another Unvented cylinder so you would need the room for this.

 

[kash]

accumulator

Will google this now - I think the plumber mentioned this

Is the main adequately sized to the Unvented, do you know what your water pressure? An Unvented will only be as good as your incoming supply and pipe sizes for pressure and flow rates. Do you know what pipe sizes are to your shower valve?

If all of the above are OK and correct then you could go down the route of an accumulator, however this is like the size of another Unvented cylinder so you would need the room for this.

I believe so. If i remeber correctly, I think i have 12 or 15mm pipe to the shower. And flow rate in the kitchen tap was cira 12 -14L per min. It was decent. Don't quote me on these.

I think part of the issue is that the new tank, sits in the loft space ontop of the single story extension on the side of the house. The shower pipe then runs up vertically about 1.5-2 meters to the 2nd floor loft then horizontal again before it goe to the en suite shower. (so two story house, with 1 story extension - tank and boiler is in this roof space)

I have plenty of space here or in the 2nd story loft space where the cold water tanks used to be.

 

[SJB060685]

As EvilDr has said accumulators are large, they need to be sized correctly. The give about 50% of volume boosted pressure, so a 100 litre accumulator will only give about 50 litres of boosted pressure before it drops off and needs to fill again. Because of this working principle you would need a lot of space to install the correctly sized one as he mentioned above.

 

[kash]

As EvilDr has said accumulators are large, they need to be sized correctly. The give about 50% of volume boosted pressure, so a 100 litre accumulator will only give about 50 litres of boosted pressure before it drops off and needs to fill again. Because of this working principle you would need a lot of space to install the correctly sized one as he mentioned above.

Just reading online - maybe i'm misunderstanding but it says "A common misconception. Accumulators do not increase water pressure. They simply allow the system to work at its maximum pressure capability. Each hot water system has a standing pressure and a working pressure. Just as it sounds, “standing pressure” is the pressure that exists when no outlets are being used and the water is at rest. This pressure will drop to “working pressure” when taps or showers are being used. "

So if have this installed, will I be drawing hot water from the new unvented cylinder and the cold from this accumulator, all at mains pressure - and then the shower pump drawing water from both (its a twin feed pump for both hot and cold?)

 

[SJB060685]

Yes you are right. An accumulator does not increase dynamic pressure, it just maximizes it, sorry I should have worded it better. Yes they are installed on the cold mains, hot water will be drawn from the cylinder, which in turn fills and supplies from the cold main accumulator. They can be installed virtually anywhere within the property but must be sized correctly as I said. If its boosting all outlets, hot and cold then this will be a large accumulator. What did you say your incoming pressure and flow rates is to the property? As mentioned above size of pipework, both into and around the property has a big part in what you'll achieve at outlets.

 

[EvilDrPorkChop]

Just reading online - maybe i'm misunderstanding but it says "A common misconception. Accumulators do not increase water pressure. They simply allow the system to work at its maximum pressure capability. Each hot water system has a standing pressure and a working pressure. Just as it sounds, “standing pressure” is the pressure that exists when no outlets are being used and the water is at rest. This pressure will drop to “working pressure” when taps or showers are being used. "

So if have this installed, will I be drawing hot water from the new unvented cylinder and the cold from this accumulator, all at mains pressure - and then the shower pump drawing water from both (its a twin feed pump for both hot and cold?)

Before considering any of that you need to check your static and dynamic water pressures, and flow rates (At a outside tap, kitchen tap and shower).

Other things to consider are whether dirt has got in the system when you've had the upgrade and whether the filters on the shower are possibly blocked...

A picture of your install might help too of the cylinder and components.

 

[kash]

Before considering any of that you need to check your static and dynamic water pressures, and flow rates (At a outside tap, kitchen tap and shower).

Other things to consider are whether dirt has got in the system when you've had the upgrade and whether the filters on the shower are possibly blocked...

A picture of your install might help too of the cylinder and components.

I'll take some pics tonight and try and do some measurements too.

 

[ShaunCorbs]

Just for your info an unvented needs a min of 3.5 bar and 20 lpm