Kitchen plumbing from sink to outside tap help

[MattLaw]

Hi there,

My girlfriends mother has just moved into a bungalow in Spalding which was owned by an elderly lady and is quite dated.

The kitchen only has a main water supply (15mm) that goes to a wall mounted water heater and then onto the cold kitchen tap. She wants water for a washing machine, dishwasher and finally an outside tap.

The 15mm mains comes out of the floor, into the loft and then back out to the sink.

I will be removing the water heater so the mains will go straight to the cold tap.

Can someone clarify that it is ok to run all the appliances and the cold tap from this run? Will I need to take the mains 15mm pipe into a 22mm pipe which will run to the last appliance (with 15mm feeds from the 22mm to appliances and kitchen tap) and then just 15mm pipe at the end going to the outside tap?

So basically I want to know if I should take the mains into a 22mm pipe before going to anything along the rest of the system so that there is enough flow for all the items above?

I'm aware of the check valves etc needed for this installation (currently at college but not done a lot of manual work!).

Many thanks
Matt

 

[stanrog]

Provided you have adequate mains pressure, 15mm should be ok. In addition to the run you will have, I have a downstairs cloakroom and all are fed from 15mm mains. It is worth noting that there will be few, if any occasions when all are drawing water at the same time and for any length of time.

 

[MattLaw]

The pressure just didn't seem very high (I have no means of testing). If this is the case will a 22mm pipe be better for the job?

 

[MattLaw]

Ok then, what tool do I need for measuring the pressure and what pressure would be ok?

 

[MattLaw]

Anyone?

 

[bathroomswap]

Surely going from a 15mm pipe to a 22mm pipe will result in lower pressure, albeit the same volume of water ?

 

[MattLaw]

I'm not sure to be honest, that's why I am asking.

 

[MattLaw]

Anyone? I will ask my college tutor tonight but it would be nice to get all the bits I need this afternoon.

Thanks
Matt

 

[slippyr4]

Surely going from a 15mm pipe to a 22mm pipe will result in lower pressure, albeit the same volume of water ?

Same static pressure, reduced pressure at maximum flow.

You will almost certainly be able to run every cold service in the entire house off a 15mm supply without problems.

In my house, when i moved in, I had kitchen sink, outside tap, 2 toilets, bath, 2 wash basins, washing machine, all on one 15mm pipe.

I then added a cold water storage tank to it, still fine.

I have since replaced this with 22mm. But the reason for using 22mm was to reduce the water velocity in the pipe; which has made cistern fill significantly quieter.


A very crude way of testing pressure is to see how much height you can get a jet of water out of your hosepipe. It'll usually reach the roof of a 2 storey house.

 

[MattLaw]

Thanks slippy, that's just the answer I was looking for.

Chances are all will be fine as I'm sure all the appliances and taps won't be working at the same time.

Cheers mate!