Request for a bit of advice on low hot water pressure

[np223]

I'd kill for some good advice on boosting the hot water pressure coming out of my kitchen sink.

I replaced the old two-tap system with a two-pipe monobloc mixer on the weekend. The flexi-pipes entering the new mixer are a bit smaller than the pipes previously used (12 mm now, 15 mm before). The cold water is mains pressure and the hot water comes from an electrical cylinder located one floor up. There used to be plenty of hot water flow but, since replacing the tap, this has slowed to a trickle. The cold water pressure is still fine.

Any advice on what I can do to boost (equalise?) the two water pressures? At the moment, the hot water is so slow as to be unusable. Will any of the following help?

1. Install a pressure equalising valve just before the mixer (maybe it's also possible to buy one of those new-fangled valves that boosts the hot water pressure by using the cold?)
2. Buy a different mixer with feed pipes of 15 mm diameter (is this possible?)
3. Put in a pressure pump on the hot system (would this be cost effective?)


Any way, I'm at a bit of a loss, so anything you could tell me would be very much appreciated.

Thanks a million!

 

[Agile]

This is a fairly common problem because you did not know about the flow rates when choosing your new taps.

Most cheaper taps are made in Italy where the hot and cold are at mains pressure of about 3-4 Bar compared with 1-2 Bar here ( if yo are lucky ).

Your hot water seems to come from a gravity fed HW cylinder.

You can either get taps more suited for your HW pressure and they would usually have 15 mm tails. Or you can install a pump in the hot water feed to the kitchen tap. A shower pump for example.

I assume the bathroom all works fine and you have no flow problem there.

Tony Glazier

 

[np223]

Thanks a lot for your insight!

It's true that the flow in the bathroom is fine.

Is there any reliable way of telling the gauge of the flexi pipe "tails" attached to a tap? I'd be quite happy to return the other tap and buy online if possible. Otherwise, I suppose that a trip to Wickes or some other plumbing store is in order?

Should I take it that the equaliser/booster valves aren't a terrific option?

Thanks again to everyone!

 

[bathjobby]

since replacing the tap, this has slowed to a trickle

Is it really 'a trickle' ? because if it is, it shouldn't be. If your hot water cylinder is 1 floor up then (37ft head = 1 bar) you have at least 0.3 bar at the downstairs tap which should be ample (upstairs gravity fed showers operate ok'ish at 0.1 bar (with the correct shower head)).
Maybe the washer / ceramic disc is sticking in the hot ! Worth a quick check as its not uncommon.

 

[np223]

Yep, I'm afraid that the hot water really does come out at a slow trickle. It is gravity feed, but the (pricey!) Italian tap seems to reduce the diameter even further than 12 mm at the cartridges.

There's nothing jamming in the mechanism. I've disassembled it and checked. I've also swapped the feed lines so that hot water goes through the cold flexi-feed and vice versa. Same problem, I'm afraid.

Any further ideas?

Thanks over again!

 

[bathjobby]

Afraid not, you have done all the logical things. Was it advertised as suitable for gravity fed (low pressure) systems ? Where did you get it and what is the brand name (so we know to avoid it) ?

 

[bobw1956]

have u checked the flexy hose is not kinked

 

[np223]

Thanks for the suggestion: the flexi-hose is not kinked.