Very poor hot water pressure through kitchen mixer tap

9 Jul 2021
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United Kingdom
Hi everyone,

We've just moved in to a property and the kitchen mixer tap has very poor hot water flow (from HW cylinder), while the cold water (from main) is fine, and they can't seem to mix at all. I understand the main cold water has higher pressure, but even when I move the tap to hot only, the flow is still extremely poor.

I have disconnected the hot tap and check the flow directly from the pipe and its perfectly fine. I suspect it is something to do with the cartridge (it is the 35mm mixer cartridge However even after I changed the cartridge, nothing has changed.

Where do you think the problem is? Is it inherent problem of mixer tap, or there is something I can do?
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It's open vented.

Its one of those typical pull out, single lever kitchen. Are they generally not for tank feed?
Check your taps specifications ,it will state a minimum recommend pressure.
Very unlikely to be suitable for most domestic ,gravity fed supplies.
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Check your taps specifications ,it will state a minimum recommend presdure.
Very unlikely to be suitable for most domestic ,gravity fed supplies.

I didn't buy this one so dont know how I can check the specification.

What type of kitchen tap that is generally suitable for gravity fed supply?
What are the rest of your hot taps like ,bath, basin,shower etc ? You could consider fitting a pump .
Most monobloc taps performance on gravity fed systems leave a lot to be desired ,and will never match the cold mains .
Some are sold as being " suitable for low pressure systems", but you won't find any where the gravity hot flow is as good as the cold mains flow.
Dual flow taps (mix at the spout) are the best monobloc taps for gravity systems. Even mix in the body taps that state they are low pressure can struggle with supplies that aren't balanced if the difference is significant and they use flexi pipes.
@Madrab Are dual flow taps are generally the monobloc type with separate handle/catridge for hot and cold?
Yes, 2 separate valves that then mix at the end of the spout, that way there's no resistance from a higher pressure supply.

The single level cartridge types always mix in the body/cartridge and therefore one can overwhelm the other and invariably need mains pressure on both sides to operate properly. That being said you do get mixer taps that have 2 valves but mix in the body and can suffer from the same problem.

A dual flow tap specifically has 2 separate streams through the spout and only mix once it gets to the end.

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