Hot water flow rate

[matt80]

Hi,

I've just had a new bathroom installed and have found that the flow rate for the hot water from the sink tap is very low. It is a francis-pegler mixer tap and it is very difficult to get an even flow of hot and cold water (thereby achieving warm water) because the cold water is so dominant.

None of the other taps in the house suffer from a low hot water flow rate. The guy who installed it has offered to fit a pump for the water coming from the hot water tank (I don't have a combi). Does this sound reasonable or is this a bit of overkill? Would it be noisy? Could it just be a problem with the tap itself?

Any help would be much appreciated

Cheers,
Matt

 

[Softus]

It sounds as though you have unbalanced supplies to the tap - does the cold come straight from the mains?

What the manufacturer say about the minimum pressure for this tap?

 

[weareleeds]

Poor flow rate @ hot because of small diameter pipes leading to mixer tap

 

[Softus]

In that case, since we're into making statements of the bleeding obvious, I'll just point out that it's Saturday today.

 

[Nige F]

Captains log ..stardate saturday .......I actually have some sympathy with the original installer .......because Frank Pegler USED to be a respected manufacturer of British brassware and I`d have thought the co. could make a low pressure mixer .......or NOT

 

[The_Scotty]

Potentially I have a similar problem. HW is piped from the boiler in 15mm copper. Is that too small a pipe for a decent flow rate?

 

[Slugbabydotcom]

Potentially I have a similar problem. HW is piped from the boiler in 15mm copper. Is that too small a pipe for a decent flow rate?

Potentially this is a topic hi-jack. Problem here is the mixer not being suitable for high cold pressure and low hot pressure. A lot of manufacturers are making taps for equal high pressure to the Hot and Cold. These taps have pipes that are too small for the job and sometimes non return valves that are totally inappropriate for older systems. Your question about the 15 mm feed to your hot taps has been answered but it is worth noting that if you want mixer taps on your sink that you will need one that can handle the mixed pressures.

Mains pressure cold is usually at about 3 bar
A hot water supply fed from a tank with a 3m head is 0.3 bar

If a mixer doesn't have separate waterways for the hot and cold the two pressures will 'fight' and the highest pressure, the cold, will often win making it difficult to get an adequate 'mix'

In the case of the holder of this topic; matt80 the answer would be to run H&C into the bowl seperately or get an appropriate tap.

Btw a sink is found in a kitchen and is used for culinary preparation etc.
A basin is usually found in a bathroom and its purpose is personal hygiene.

 

[matt80]

Hi,

Thanks for the advice. I have had a look for a tap that handles different water pressures but haven't been able to find any - could you give me an example of one, or tell me what terms I should be looking for?

Cheers

 

[Softus]

Thanks for the advice. I have had a look for a tap that handles different water pressures but haven't been able to find any - could you give me an example of one, or tell me what terms I should be looking for?

I think such a tap doesn't exist.

If you have mains cold going to the tap, then you need a kitchen mixer, which isn't really a mixer, or a bath filler.

The only other way out is to pressure limit the cold supply to the tap with a pressure limiting device.

 

[matt80]

Thanks Softus...

What do you think about the suggestion of adding a pump to the hot water supply to increase the pressure? Is this overkill or a decent solution?

 

[Softus]

Sorry - touch of brain fade there - I shouldn't have said the only other solution is a PRD.

A Pump is a fine solution - one of these would probably do:

http://www.stuart-turner.co.uk/products/building/showermate12.htm

You need to make sure that the pump can't be starved - the traditional method is Surrey/Warix/Essex flange on the cylinder. My personal favourite is the Essex.

 

[Slugbabydotcom]

Providing a tank fed cold for the mixer would do the job but at the kitchen sink you would also have to run a separate supply from the mains for drinking water.... Not a good way to deal with it
The sort of 'mixer tap' you are looking for will have a separate core in the spout ie. 2 waterways for hot and cold respectively.

Softus is quite right in that it doesnt actually mix the water

 

[matt80]

That pump is for showers, can it be used for taps aswell? Will it be nosiy... I have a shower pump at the moment that is quite noisy and would get annoying if it was that loud everytime i turned on a hot tap...