Hot Water Flow In Kitchen Sink.

[Tilly2]

Has anyone any idea as to why the hot water tap in the kitchen is so pathetic? We did have a Homeserve plumber have a look at it and he said it was probably an air lock but didn't do anything about it. The rest of the taps in the house are fine and the cold water, from the same dual swan neck tap, comes out fine. When we switch from cold to hot, the pressure is minimal and it takes ages to fill a bowl with hot water in the kitchen sink.

[Tilly2]

Thank you Mr B. There are braided steel connectors used to connect to the underneath of the tap. We also have a built in water filter, so the tap actually has three on/off levers.

Maybe we should be looking at a Combi boiler or changing the tap. :-)

[The Builder]

The filter shouldn't matter Tilly. It's on the "cold" supply.

The braided connector on the "hot" may well be the problem.
Only a problem though if the mixer is NOT rated for low pressure.
Without the make and model I'm afraid I can't say.

[Tilly2]

I have the paperwork somewhere, Mr B. I'll have another look tomorrow. I do know it's a Franke, swan neck, three way chrome tap.

[Togo]

Can we ask Tills, is the hot tank upstairs or even in an attic or loft? If you live in a bungalow(I do) you do not have much of what is called a "head" of water. (no weight behind it) The bottom of the tank is therefor liable to be only about 4ft off the floor. The hot out pipe is going to be at the bottom(obvs). Your bath and bathroom basins are going to be fairly low but if you put a swan neck tap on a 930mm kitchen worktop sink then you have just halved the pressure if the swan neck tap is one of the Franke bigguns. ( the top of the swan neck will determine the height). It may even be above the tank outlet. That would reduce the hot pressure/flow without any other restrictions like the armoured connector link as well. You are basically trying to deliver hot water through a straw ... uphill.

[The Builder]

Ok, Tilly. I'll look in tomorrow.

So, it's one of those fancy ones?
Most of them need about 1.5 or maybe 1.0 bar of water pressure.
Assuming you are 2-storey, with a tank in the roof... that will probably be only 0.5/0.6 bar pressure.

I'll wait and see, but that may well be the problem.

[Togo]

// You are basically trying to deliver hot water through a straw ... uphill.//

Made my eyes water when I typed that Tills. (￣ i ￣)

[Atheist]

Tilly; is the problem a recent thing, or has it always been like that? If it's only recently started then something must have happened. If it's always been like that, then Builder's comments about tank height and available pressure are more relevant.

[alavahalf]

The fact you do have a some flow, says you don't have an air lock.
In a gravity fed system you need to allow the water to flow a easily as possible.
The first thing I would do is have a look in the water tank.. In the past I have removed pigeons, mice and even a rat from loft tanks. Any of these would reduce the flow.
Failing that I would be looking under the sink. The flexible braided hose could partially collapse after some time. I always carried flexible pipes with a larger bore, increasing the pipe diameter by a couple of millimeters could increase the flow by thirty percent.
The other culprit that will reduce the flow is the service valve. Nearly all of them reduce the flow. In a gravity fed system I would only fit a 'full bore' valve.

[Tilly2]

Two storey house and the hot water tank is in the airing cupboard on the first floor. The cold water tank is in the loft, second floor, I presume.

[Tilly2]

Atheist, I have only recently been bothered by the pathetic hot water flow from the kitchen tap. It's been fine for the last eight years.

Maybe a Power Flush would help the whole system?

[Tilly2]

Alava, when can you come and fix my tap? You seem to know what you're doing. x

[Atheist]

Power flush usually applies to the central heating radiators. I think an intelligent plumber should be able to find and rectify the problem - it sounds more like a blockage than an inherent design fault.

[Atheist]

I bet alava could diagnose in a jiffy if he was there.