Boosting kitchen hot-water pressure

[Martin Bonner]

Apologies if this ends up as a duplicate post. I tried to post via a website, but it doesn't appear to have got through.

We are redoing the kitchen, and SWMBO has decided that we want some Perrin & Rowe taps with a spray attachment. The only problem is that it specifies it needs at least 1 bar pressure. Dredging up the facts from my rather distant diving days, that equates to a static head of 10m; I am pretty sure the header tank is at least 2m above the kitchen taps, and it might be 3m, but that still leaves me at least 7m short :-(.

The full solution would be to pull out the boiler and replace it with a combi - that would also mean we could move the boiler to the other side of the kitchen, and generally smooth things up. It would also probably triple our budget.

I think I need a pump of some sort. What does the group suggest? I don't think I have a problem with the cold water pressure (it comes out of the tap feeling as if it pushes pretty hard). Also I get the impression that connecting a pump to the mains is a bit of a no-no.

My other concern is that if I end up with more pressure in the hot water than in the mains, is there a risk that if somebody puts their finger over the end of the tap (who? me?) I will end up pushing hot water back into the mains?

-- Martin Bonner

From address is genuine but never read. Preferably reply to the group, but if you mail my name (with a stop between) at pitechnology dot com, it will get to me.

[John Stumbles]

Grundfos do one for this sort of application: it's like one of their central heating pumps with a flow switch to turn it on when you draw water. I think it's called a Home Booster or summat like that. Costs about 100 notes, mind :-(

I think DPS sell them (google)

Should be direct from the mains

Also I get the impression that

Correct :-)

Not unless both your pump and your finger are in the Arnie mould ;-)

[Christian McArdle]

I would suggest that if you are adding the pump, you should pump the entire hot system for better bath and shower performance. A heavy duty single impellor shower pump is what you need for this. The cold system can remain on the mains. A thermostatic shower mixer with pressure balancing can cope with (i.e. loves) a cold mains and pumped hot feed.

If the kitchen tap doesn't mix at the spout, which appears likely in your case due to the hose attachment, then you should install double check valves on any mains fed supplies to it. (Just the cold in your case). However, I'd fit to both supplies to prevent the hot water being pushed back, too, although it isn't a legal requirement.

Christian.