Low pressure hot side bath mixer tap

[osburn fernandes]

I came across a job the property has a combi boiler upstairs sink next to the boiler had hot and cold similar pressure mixer tap. there is a bathroom down stairs where the hot comes in T’s off into the basin tap good pressure same as cold side basin tap. Then the pipe finishes off in the bath tap also a mixer tap ive replaced the bath tap for a new one basic mixer tap. No fittings between T for basin and bath. Ive cut the copper off under tap and swaped em for flexi. Pipe work in the bathroom running on 15mm copper. But the water pressure is still not same as the cold mains pressure Its moderate. Any advice

 

[Burger]

Any photos available? Any restrictions on flexi? Any hidden valve?

 

[osburn fernandes]

No restrictions brand new flexi and tap only thing is its 15mm pipe leading up to the tap dont know if its the cause. I dont kniw if its because its a 3/4” outletfrom a 15mm pipe.

 

[Stu-B]

Actual measured pressure or just “holding your hand under” pressure.

 

[Fantic156]

Pressure or flow rate?

 

[Roy_66]

If you havent creased the hose and only change is the hose and the tap, then does that indicate faulty tap, unless some crud dislodged somewhere. I'd take hose off tap (isolate first at the house main stop tap ) then fit a free standing drain valve to end of hose. Typically drain valves are 1/2inch bsp so if your baths are 3/4inch then you may need an adapter. Remember if measuring bsp its the inside dia of the male i.e. the tap. Go to good plumbers merchant if not sure. If not helpful find one that is (and remember we all have off days - well most of us).You can then do flow test into bucket. Alternative if you have a helper, you could point the disconnected hose into bucket while somebody else turns on the main stop tap (just half a turn). Dont do that if they cant clearly hear you shout "turn off !". What is the bend on your hose when fitted to tap ?

I'm assuming here your taps are UK BSP threaded connection ?

Here's an example of the test bits for 1/2inch BSP hose (The adapter if you need in my hand to convert to 3/4inch BSP):

e.g. Drain tap (from plumbers merchant or DIY):
Drain Cock Type B - 1/2" BSP Brass - 6922 | BES.co.uk

e.g. Adapter (The plastic one is ok for testing, not for any final installation) you can get this from DIY or garden centre, or ask plumbers merchant. Make sure there is sealing washer in the female end of the adapter:

https://www.amazon.co.uk/Hozelock-26-5mm-Outdoor-Threaded-Connector/dp/B000TAW5WW

Important point. If your nice new taps have ceramic valves then always flush through your new plumbing before fitting the taps else crud can damage the ceramic inserts (from experience on my own bath taps). If you have been soldering then you need hot water flush for that. So test bits like the above are very handy to have, also for fault finding. Get some female stop ends at same time for future projects.

P.S. Post title might be better as "poor flow at hot bath tap (high pressure fed)"
(I'm also checking my understanding here)

 

[Millsy 82]

Generally water won't be under the same pressure from a bath tap as it's going through a bigger hole.

What you want to measure is your flow rate. Get a bottle/ jug and measure how long it takes to fill that compare that with the basin/ sink.