Ed Sirett wrote:

Generally the two hole mixers tend to be suitable for lower pressure
supplies. Has the end of the spout got an aerator?

My kitchen mixer tap has always been slow on the hot water side, around 3
litres/min whereas my bathroom single hot tap (immediately above the kitchen
& fed from the same supply) is around 6 litres/min.

Logic tells me it should be the other way around.

Does the presence of an aerator indicate a high pressure tap or would
removing it help matters?

Dave

david lang wrote:

My kitchen mixer tap has always been slow on the hot water side, around 3
litres/min whereas my bathroom single hot tap (immediately above the kitchen
& fed from the same supply) is around 6 litres/min.

Logic tells me it should be the other way around.

Why? Kitchen cold tap will be at full mains pressure, and your bathroom
cold tap evidently is too (and is close to the point of entry so the
flow won't be throttled back by a long length of pipework.

You don't say whether or not your hot water is at mains pressure too. If
it *is* at mains pressure, then the large differential with the cold
flow would suggest a partly closed valve or blockage somewhere; even if
not, you'd expect slightly less flow rate than in the cold because
there's more pipework between the hot taps and the incoming rising main
(which creates the pressure) than there is between the cold taps and the
rising main.

OTOH, if the hot water is *not* at mains pressure, the the hot water
pressure will presumably be generated by the height of a cold water tank
sited in your attic or similar; and unless you have really low mains
pressure, the hot water will inevitably be at lower pressure than the
cold in such cases.

So either way, your cold water would be expected to flow faster than the
hot.

David

David

Lobster wrote:
Why? Kitchen cold tap will be at full mains pressure, and your
bathroom cold tap evidently is too (and is close to the point of
entry so the flow won't be throttled back by a long length of
pipework.

I'm not talking about cold taps, they are fine. It's just the hot taps.
The kitchen tap should have a greater 'head' because it's further below the
tank.


You don't say whether or not your hot water is at mains pressure too.

No, from a cylinder.


OTOH, if the hot water is *not* at mains pressure, the the hot water
pressure will presumably be generated by the height of a cold water
tank sited in your attic or similar;

Thats right.

and unless you have really low
mains pressure, the hot water will inevitably be at lower pressure
than the cold in such cases.

I know that, as I say the cold is fine, its the difference between tqo hot
taps I'm asking about.

Dave

david lang wrote:
Lobster wrote:

Why? Kitchen cold tap will be at full mains pressure, and your
bathroom cold tap evidently is too (and is close to the point of
entry so the flow won't be throttled back by a long length of
pipework.


I'm not talking about cold taps, they are fine. It's just the hot taps.
The kitchen tap should have a greater 'head' because it's further below the
tank.


You don't say whether or not your hot water is at mains pressure too.


No, from a cylinder.


OTOH, if the hot water is *not* at mains pressure, the the hot water
pressure will presumably be generated by the height of a cold water
tank sited in your attic or similar;


Thats right.


and unless you have really low
mains pressure, the hot water will inevitably be at lower pressure
than the cold in such cases.


I know that, as I say the cold is fine, its the difference between tqo hot
taps I'm asking about.

Ah, sorry - misunderstood: thought you meant you were comparing H vs C
in bathroom and kitchen.

Could the problem be a partly closed service valve in the kitchen or
elsewhere in the pipework?

David

david lang wrote:

My kitchen mixer tap has always been slow on the hot water side, around 3
litres/min whereas my bathroom single hot tap (immediately above the kitchen
& fed from the same supply) is around 6 litres/min.

Logic tells me it should be the other way around.

Does the presence of an aerator indicate a high pressure tap or would
removing it help matters?

Chances are you have a kitchen tap designed for mains pressure (many of
them are). They still work on low pressure (usually - although some
quarter turn mechanisms will fail to turn off properly without
sufficient pressure), but you don't get the flow rate.

--
Cheers,

John.

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