hot water cylinder

DELLBOY_2

looking at installing a non vented water cylinder run from electric only .
needs to run a shower so how can i check the water presure will be enough ?

also how efficient is the heat transfer and how big should i go ??

PaulF81

Whatever the water pressure going into the tank will be - static head - a little bit for pipe friction losses = pressure at the shower head.

If you are in a poor pressure area, your shower pressure will be poor. We are in an area that meant we had to have our water pressure regulated down from 6 bar to 4. This was upstairs.

As a rule of thumb, for every metre above the inlet point the shower head will be, you need to take 1 bar pressure off for static head. The only way round this is using a pump to boost pressure.

unclebulgaria

I'm not sure you've got that right PaulF81.
Take a pressure reading from an outside tap that's connected to the rising main. You can buy a wet pressure meter from a plumbers merchants.
If its 4 bar standing pressure then that's 56psi of water.
Divide the height of the tank from the ground floor by 2.31 then take that off your 56 psi that should be your pressure at the tank.
Just a point, if you're not qualified to fit un-vented cylinders then I'd be careful when you carry out the work.
It cost me a lot of money and time/experience to fit these and if you don't do it right it could be dangerous. You have minimum requirements for safety on these installs for a good reason.
If you require a pressure from a cold water tank just work out the distance from the cold water tank to the shower head. Its .1bar per metre pressure.

PaulF81

Sorry, you are right! One of those engineering conversion factors in the back of the head that I got the decimal place in the wrong point (not a plumber, but I am a qualified engineer).

Fully agree on the unvented system install, this with gas is one of the 2 systems I dont meddle with... there are some pretty nasty youtube vids of people having had their roofs taken off when the safety features havent been installed properly or even disabled!

All i intended was to offer a quick and dirty for the op to carry out some basic calcs for system viability, before they have to get into pumps etc.

General rule of thumb with an unvented, good water pressure in = good water pressure out!

unclebulgaria

PaulF81 wrote: »

Sorry, you are right! One of those engineering conversion factors in the back of the head that I got the decimal place in the wrong point (not a plumber, but I am a qualified engineer).

Fully agree on the unvented system install, this with gas is one of the 2 systems I dont meddle with... there are some pretty nasty youtube vids of people having had their roofs taken off when the safety features havent been installed properly or even disabled!

All i intended was to offer a quick and dirty for the op to carry out some basic calcs for system viability, before they have to get into pumps etc.

General rule of thumb with an unvented, good water pressure in = good water pressure out!

Hey no probs. I thought it may be the decimal point.

DELLBOY_2

ok so my presure appears to be ok but what about the heat transfer and size of tank required ?

gas4you

Your G3 registered fitter will tell you all about that.

DELLBOY_2

I like to get views from other people as well as the guy im paying as he might just have a vested interest

southcoastrgi

DELLBOY wrote: »

I like to get views from other people as well as the guy im paying as he might just have a vested interest

so you already don't trust the guy you say you are going to use, thats a good start ain't it, as you have already asked the questions about water pressure me thinks you are going to fit it yourself & as you must be certified to fit these you aint getting any advice from me

DELLBOY_2

well thanks for that, i think its a good start to get as much imformation on a product before you decide on spending the money .
after all would you buy a new car tv or washing machine just from the chat from the salesman or would you maybe ask some one who has bought one or check out the reviews in a magazine like which .
Surely thats a better approach isn't it ?