Hot water Presure to Bath

[rdo1104]

Hi Again,

I've had a new 22mm feed put into my new bath as the pressure was poor (probably because I'd run a 15mm feed - doh). On completing the work it did sohow somw minor improvement but nowhere near what was expected. The plumber has advised that the tap is a continental one which only has 10mm inlets which he says are designed for pressure systems - mine is gravity fed.

I could get a new tap with 15mm inlets which I want to try and avoid due to the cost but was wondering if there are any pumps on the market for this type of scenario i.e. a single feed in line pump - any advice on this would be good

Thanks
Rhys

 

[Gunslinger]

10mm feeds to a bath tap are small, however may be common in europe (i'm not sure)

the only ones i've seen that are narrow like that are kitchen sink or basin taps, and i have seen suggested that swapping the braided flexi hoses to the tap for larger bore ones may help ease the problem, but i'm not 100% sure this will work, as the basic internal tap design will more than likely be narrow for use on pressured systems.

how is the 22mm pipe connected to the tap ? is it via braided flexi hoses ?

There are a number of pumped solutions available, ranging from single ended to twin, and at various pressure and flow rates, so it should not be too difficult to find one that will increase your hot pressure/flow rate, to something similar to that of your cold supply, just remember that you cant put a pump on the cold mains directly, so a twin ended one is unlikely to be what you want, and, you will need non-return valves fitted to both the hot and cold supply lines just before the tap, this will also likely affect your cold pressure, so do this first and test it before you go and buy all the other parts you need, or you'll be mighty annoyed if the non return valve reverses your current problem.

Also check the pump manufacturers preferred / recommended method of connection to the hot tank to avoid aeration

 

[rdo1104]

Thanks Gunslinger.

The cold feed is via 15mm, mains supplied and uses a flexi to reduce to 10mm. The hot feed (new one) is 22mm all the way to just short of the connector which then reduces to 15mm then to 10mm. Forgot to mention that this is one of those fancy taps which has individual hot / cold taps and a separate filler + a showevr connector. They are all connected through a brass fitting underneath the bath. This brass fitting does not have flexi connectors.

Also, I got a bit confused with your response about potentially reducing the cold water flow. Why do I need to add none return valves? I had envisaged just adding an in-line pump in the loft on the 22mm hot feed - apologies if I'm completely going off on the wrong path

Thanks
R

 

[Gunslinger]

Water regulations require a non return valve fitting to prevent back flow into the mains from stored water supplies.

on a practical point, you dont want a high pressure on one side of a mixer valve and low pressure on the other, as it will have a tendency to stop the flow from the lower pressured side, or at least reduce it so as to make getting a stable temperature out difficult

you would normally position your pump either near the hot water tank (at the base of it) or in the bathroom, fitting in the loft is not normally an option as you dont want the hot tank higher than the pump. The hot feed i assume comes from the tank in your airing cupboard, simply put the pump in there with it.

If your on a combi boiler and have no hot storage tank, then thats a whole different ball game (i am assuming however that you do have a hot tank, as you said the system was gravity feed)

 

[rdo1104]

Gunslinger

All my tanks etc. incuding hot water cylinder are in the loft so I guess I am okay to go ahead with a pump in the loft as long as it is at the same level as the bottom of the tank.

Also, are the return valves easy to get hold of and will any plumbers merchants hold them?

Cheers
Rhys

 

[Gunslinger]

ah ok, didnt figure on your hot water tank being in the loft with your cold storage tank !

yes the non-return valves are easy enough to get, there are a couple of different types available, for different purposes, not 100% sure if you will need what is referred to as a "double check valve" or if a "single check valve" will suffice, have a quick search around here as i'm sure the info will be available, unless someone else can chip in with the exact info required.

Sometimes, but not always, the valves are supplied with the pump, or can be bought from the same place as the pump if not

 

[Gunslinger]

have a look around these 2 links as the info you need should be in there

http://www.wras.co.uk/Get_a_copy.htm

http://www.arrowvalves.co.uk/content.php?id=9