Tap for a gravity based hot water system

[Niall_Glasgow]

Hi,

I have a gravity based hot water system, and recently had a new kitchen installed. We never had a noticeable hot water pressure issue before, but the flow from the new tap is down to a trickle.

Pressure head is c.3m. Flow is 2L/min compared to 12L/min minute out of the hot water tap upstairs. The new tap has a minimum pressure of 0.5bar, so presume it just the wrong tap.

Plenty of taps on Screwfix suitable for gravity based system with min pressure 0.1bar, but a read of the reviews for most of them suggest you still only get a trickle for a gravity based system.

Looking for someone who has experience of this issue to recommend a tap that will maximise the flow? Any help much appreciated.

Thanks

Niall

 

[Ben-gee]

Get one with compression valves.
A good one is Franke Rotaflow

 

[Deleted member 120897]

Have you had the kitchen fitters back? Has a flow rate been checked without the tap fitted? Has any investigation work been done to ensure it is actually the tap? Is the tap a lever type?

 

[fowlerboi]

I believe most kitchens come with a clause saying the tap they provide might not be suitable for low pressure which is a massive cop-out on their part as they can't seriously expect customers to understand that. The fitters need to be held a little bit accountable.

Is your tap upstairs a pair of hot and cold taps or a mixer? If its a pair then the hot supply to the tap will likely have 15mm pipework while your new one downstairs may be on flexible pipes with only an 8mm bore and even more restrictions inside the tap hence why it wants 0.5 bar.

You say your head is only 3m but your kitchen is ground floor and bathroom is upstairs? Where is the cold water storage cistern located?


If its in the roof then you may be close to 0.5bar. Typical ceiling heights would be 2.2-2.4m. Your tap will be 1.3m off the floor so 1m to the ceiling, the next floor would be 2.3 and then the water level of the cistern will be likely 0.8m off the deck, then add in the joist depths of 0.2m x2 for each floor you get 4.5m of head or 0.45 bar.

If what I said above is correct I would probably change the tap for a 0.1 bar tap with 12mm connections in the bottom and ditch the flexi's and use copper tap tails (unless they come with large bore flexi's.) A picture of the inside of the kitchen cupboard will also help us eliminate any restrictions the kitchen fitter may have caused such as non-full bore isolation valves