Alternative solution to increasing water pressure?!

[HeartyHail]

Hi everyone,

we've just moved into a upstairs/downstairs house and first night discovered that the water pressure for the shower was less than poor! (Lesson learned for viewing our next place to rent!)

Anyway, the managing agent sent round a plumber who very quickly said there was two options:
electric shower
fit a water pump

After a brief look online I've seen a third option (Pressurised Unvented Cylinder) but generally its only those 3 solutions that are mentioned. I'd like to suggest another and maybe someone can tell me why it won't work! Lengthy story to follow!! :smile: (by a non-plumber!)

So our system is fairly standard/common. We have a header tank in the loft, fed from the water mains. The header tank supplies all the cold taps in the house, as well as a vented hot water cylinder (directly below on the 2nd floor). There isn't a combi boiler, its an old condensing boiler I think (Potterton 40el) in the kitchen downstairs.

The shower being on the 2nd floor, is only about 2 meters below the top of the header tank (short and squat), hence the poor pressure.

So for the solutions suggested:

• Installing an electric shower means that the hot water tank would then only supply the hot water taps in the bathrooms and kitchen sink. Since there is a fairly new dishwasher and new washing machine, we'll hardly use any hot water from that (what a waste to keep the tank heated and ready) .
• Installing a pump means we're using electricity to provide pressure, when there's already water pressure from the supplier, "in the street" ( a waste of electricity, our money not the landlord's)
• Installing a pump or electric shower, means using (more) electricity to solve the problem.

I guess the unvented system would be more expensive than these options.

Also, I'd really like to do away with our potable water going through the header tank (at least the cold) , since it didn't look so great in there...

So I thought, why not fit a pressure reduction valve from the mains feed, to the "output" of the header tank (feeding cold and hot) ? The output pressure could be set at 0.8bar or 0.9bar (the hot water cylinder is rated to 10m working head, and I think that's the lowest rating) to give adequate safety margin.

That way, we get more pressure than currently, for free and get rid of the (open) water storage in the loft (and get rid of the risk of it breaking and flooding). I then realised that the hot water cylinder needed a vent, and I don't really have a solution for that. Other than maybe just venting it as an overflow into the garden or drain (like an overflow). How much water would be wasted like that? A litre a month? Liveable.

Why isn't this a solution thats mentioned? Have I overlooked something?

Most pressure reduction valves I've seen are minimum 1bar, but I did find one ( a FIG 800 by Nabic http://www.nabic.co.uk/resources/db/Fig 800 & 850 Pressure Reducing Valves.pdf ) that was suitable for potable water and UKWFBS approved and minimum outlet pressure of 0.5bar . So they do exist .


An alternative would be to feed the cold water directly from the water mains. That way, we get high presure for our shower and the rest of the house, our drinking water isn't going through the header tank, and the mix of hot/cold water in the shower would mean we'd probably need to fully open the hot tap and keep the cold almost turned off, but we'd live with that. Is that a possibility?

Thanks for any answers !

Hadyn

 

[HeartyHail]

So I've just read for CW fed from mains and HW from the tank, I'd need non-return valves for all mixers in the house. That's probably not going to happen so I guess that leaves only my first suggestion , of a PRV feeding the CW and HW tank, meaning nearly equal pressure in the cold and hot pipes.

Additional info that may help: The kitchen has just recently been fitted out , and the bathroom doesn't look too old (maybe around 5 years) so can I guess they are all monoblocs? The shower is over the bath, and fed from the bath mixer.

 

[Simon F]

Hello HeartyHail,
A home made unvented cylinder - NO !
the fact that all your house is fed from the storage tank suggest you could have low mains pressure.
could the cold tank be raised any higher?

 

[nickelarsed]

imho far simpler to just clean your cws if you don't like the look of it, and then fit a proper lid etc. anyway your kitchen sink will already be on mains pressure. put an electric shower in is my thinking. Unvented are good but will cost you, and if your renting it's a bit ott unless landlord wants to pay.

And as said above, really, don't try and manufacture an unvented system or mess with vent pipes

 

[southcoastboile]

bad idea, well done for looking all that up and what you are saying makes sence but its just not viable. You can't do that, it could potentialy be dangerous, unvented cylinders are designed to to what you are sugesting. If it was as simple as what you said they would not exist. If its that much of a problem then you should go with the booster pump, it won't cost alot to run. Or as sugested, raise the cws tank. Are you sure its not something stupid like a scaled up shower head? have you tried running shower with the head removed? also some showers have filters on them that may block up.

 

[HeartyHail]

Thanks for the replies, and I was so hopeful!

The tank could be raised a bit, but only a meter or 2.

Downstairs kitchen does have more pressure but I thought that was due to the height of the tank, not due to Mains supply.

And the bath and basin run as slow as the shower so I don't think anything is blocking.

The plumber and electrician are coming tomorrow to assess how much work the electrics will be for shower or pump. I was hoping to insist they consider this, but doesn't sound like it's viable so I'll just keep quiet and accept whatever.

Thanks again.I'll let you know what we get..

 

[PlumbBobBob]

you could think about a whole house pump which will boost all outlets.

 

[dancinplumba]

should really have kitchen and basin taps fed with potable water for drinking, cooking and cleaning teeth,
dont drink your stored water.
imo