Best Way to Boost Flow Rate at Bathroom Hot Tap

[_Sid]

We have recently moved to a house with a conventional heating system and the tap at the bathroom sink is about a foot below the top of the hot water cylinder which is in the airing cupboard next to the bathroom.

The flow rate at the hot tap is a piddling 1.8L/min and I am considering installing a pump to increase this but I'm not sure which pump to choose or where the best place is to install it - under the sink or in the airing cupboard. Has anyone done this successfully?

 

[terryplumb]

Are other hot taps such as bath / shower valve etc flowing significantly better than that basin tap ?
If so ,check the supply pipes to basin tap for restrictive isolation valves ,braided flexible hoses that are constructed / twisted etc. that tap may not be suitable for low pressure systems

 

[ChrisJP]

The flow from your tap is not dependent on its distance below the top of the HW cylinder. It is dependent on its distance below the water level in the CW storage tank that feeds your HW cylinder. If other taps are similar distances below the CW tank level and provide better flow then, as terryplumb suggests, there must be some sort of restriction in the supplying pipework.

 

[_Sid]

Thank you both.

The basin tap is the only hot tap at that level. The shower in the bathroom is a Mira Event XS which is fed by both hot and cold and performs really well. The kitchen tap which is downstairs is OK as is the one at the sink in the garage, so I'm thinking that there is not enough head of water.

Yes, of course, it's the HW feeder tank level that determines this, I was forgetting that. This is in the loft. Should that give a sufficient head for a decent flow rate at 1st floor level?

The taps are fed through 15mm copper but they do have 90° plastic bends near where they attach to the braided pipes. They don't have isolators. The CW seems OK with this at mains pressure but maybe not so good for the hot?

 

[blup]

Getting those supply pipes direct to the tap will help flow.

 

[terryplumb]

The restriction is the small bore inner tube of the Flexi hoses. Fine for mains pressure and rubbish for gravity fed hot water where the tap is closed ,height wise,to the loft tanks base.
You could fit a pump ,but is it really worth it for a basin ?

 

[_Sid]

So maybe that tap isn't suited - must have been a cheap job!

 

[terryplumb]

To be frank most monobloc taps with flexible hoses don't perform very well unless the water is under mains pressure.

 

[catlad]

must have been a cheap job!

Thats the type of plumbing I could do, I guess if you got a pro in and got rid of the flexies then things would be better.

 

[_Sid]

Thats the type of plumbing I could do, I guess if you got a pro in and got rid of the flexies then things would be better.

Yes, I think that is the answer. Thanks to all.

 

[Madrab]

As suggested - Gravity supplies are notoriously bad when run through mono bloc mixer taps with flexible hoses - both are extremely restrictive to flow and should really only be used with mains water supplies.

You won't be able to get rid on the flexi's for that tap as that's the only inlet hoses that will fit it. Most flexi's for that type of tap are M10's being 10mm at the connection to the body of the tap. Best type of tap for a single hole basin would be one with screw down compression valves, being the ones that would offer the least resistance to flow.

 

[_Sid]

.... Best type of tap for a single hole basin would be one with screw down compression valves, being the ones that would offer the least resistance to flow.

Plumbing has never been my forte. Can you post a link to a tap that would be suitable?

 

[fixitflav]

We have recently moved to a house with a conventional heating system and the tap at the bathroom sink is about a foot below the top of the hot water cylinder which is in the airing cupboard next to the bathroom.

The flow rate at the hot tap is a piddling 1.8L/min and I am considering installing a pump to increase this but I'm not sure which pump to choose or where the best place is to install it - under the sink or in the airing cupboard. Has anyone done this successfully?View attachment 361670View attachment 361671

Is the flow from the cold tap adequate? They both see the same head, so if it is maybe the problem is something specific to the hot.

 

[Madrab]

They both see the same head

Unless the cold is mains, which seems to happen all the time - unbalanced supplies.

Can you post a link to a tap that would be suitable?

Will it be better, well as others have said there could be several factors that is affecting the hot flow - as well as the supply to the HW cylinder, sometimes the valve that controls that may not be fully open.

One such tap though would be one like this, though again the restricting factor would be the flexi supply pipes

https://www.screwfix.com/p/swirl-traditional-basin-mono-mixer-tap-with-clicker-waste-chrome/310pg

It may be an idea to have someone in to look at the setup and see that everything is working as it should. If that someone looks for 5 mins and then tries to convince you into changing it all with major expensive work then show them the door and get someone else. A gravity system like your can work very well, it just has to have the right stuff and be setup properly.

 

[fixitflav]

Unless the cold is mains, which seems to happen all the time - unbalanced supplies.

I thought of that, but didn't think it very likely. Worth checking anyway. I believe it's not allowed for a shower, as mains failure could result in scalding.