Low mains pressure/...
 

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[Closed] Low mains pressure/unvented cylinder shower question

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So I want a new bathroom and currently have an electric shower in there, I recently had a 125 litre unvented cyclinder fitted (though it does have an expansion vessel above unlike the Megaflow I thought I was getting, it does have a tundish so is pressurised)

i live in a low mains pressure area at the top of a hill though I still have an ok shower with the electric but not exactly a power shower. Can I run a shower with a mixer directly off the mains and hot water cylinder?  I want a bath tap/shower bar thing.

There is no cold tank in the loft just a cold main and the hot cyclinder fed by the mains.

evidently the flow rate is acceptable as Thames water tested it when they fitted a meter.

any advice welcome.


 
Posted : 07/05/2018 7:02 pm
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Let’s assume the unvented cylinder has been installed by a certified competent installer, then a thermo mixer shower is indeed perfectly feasible.

you say you have low mains pressure though, how low? If too low, like under 1 bar then your new shower might still be disappointing.

check your pressure, you can get pressure test gauges for little money.


 
Posted : 07/05/2018 7:31 pm
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Let’s assume the unvented cylinder has been installed by a certified competent installer, then a thermo mixer shower is indeed perfectly feasible.

Yes, I made sure the fitter was certified. (G3?)

will hopefully get a pressure tester and try it on the washing machine cold feed.

i know I can fit a pump but would like to avoid it if I can, eventually this will be rented out when i shack up with the other half. That’s partly why I want an external mixer not something buried in the wall that’s a pain to fix/maintain.


 
Posted : 07/05/2018 7:48 pm
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Yeah, avoid a pump.

if your pressure is good then happy days.


 
Posted : 07/05/2018 8:27 pm
 Bear
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You can’t pump the water main unless you meet a load of conditions.

If the electric shower works ok the unvented should do as they are driven by the same pressure.


 
Posted : 07/05/2018 8:50 pm
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Thanks for the replies/advice.


 
Posted : 07/05/2018 11:15 pm
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My shower is just off the taps, fed by mains + hot water tank (unpumped).It's pretty crap, not helped by the fact the tank is at the same level as the shower. I basically have the hot open all the way and a tiny bit of cold so all the pressure comes from the hot water feed - although I have decent mains pressure I doubt having low pressure would make it any worse. It's usable but showering takes twice as long and would be a nightmare with long hair

I'm planning to switch to a combi boiler (and new thermostatic shower) but would otherwise look at a power shower or pumping the hot water from the cylinder.


 
Posted : 08/05/2018 8:13 am
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Is that from a direct fill unvented cylinder though? I’m presuming that makes a difference.

no gas here so a combi is out of the question


 
Posted : 08/05/2018 8:48 am
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there's also the actual shower head/mixer to think about - some have a minimum pressure to work at around 2-3bar as many of the big brands are made on the continent (Hans Grohe, Grohe etc).  the reason for this is they have small bore pipework in the mixer.

you might find that if the current setup isn't sufficient, then a different mixer shower, specifically for low pressure might be acceptable.


 
Posted : 08/05/2018 10:50 am

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