I posted this last night but it seems to have got lost. Glad I saved
a copy!
On 26 Apr, 18:04, Ed Sirett wrote:
I and others can offer office chair speculations which can be
much more accurate if there are some numbers. Like ...
Standing pressure of mains cold.
Sorry, not sure how to do this one. "It belts out" is the best that I
can do
.
Flow rate of cold and hot at kitchen sink. (Ground floor)
Bearing in mind I was using a bucket to measu
COLD 11.5 lts/min
HOT 13.2 lts/min
Benchmark says 14 lts/min, for what it's worth. Not sure where that
was tested.
The kitchen cold is nearest to the stopcock but has never been great;
the kitchen hot furthest from the boiler (and the pipe is kinked).
I'm guessing that someone has fallen onto the tap at some point which
may account for the wierd cold reading (and the hot kink).
Flow rate of cold and hot at bath. (1st floor)
COLD 37.5 lts/min
HOT 12.8 lts/min
Flow rate of cold and hot at shower. (1st floor)
COLD 24 lts/min
HOT 11.5 lts/min
Remember this is actually a bath mixer. The readings on the taps into
the bath we
COLD 33 lts/min
HOT 12 lts/min
I've added a few other measurements that might help:
* Flow rate of hot shower when cold bath running.
COLD BATH 30 lts/min (c.f. 37.5 by itself)
HOT SHOWER 8 lts/min
* Flow rate of hot shower in ensuite when hot sink in bathroom on (hot
sink by itself is 11.8 lts/min).
HOT SHOWER 2 lts/min (measured with a 1/2 lt jug as I couldn't be
bothered to wait the estimated 5 minutes to fill the bucket
)
* Flow rate of cold in cloakroom (~2m before hits boiler). (Ground
floor)
COLD 27 lts/min (actually probably higher - I couldn't open the tap
fully without the water escaping the basin)
With a 40kW combi you really should be able to run a shower and bath
together.
Nice to know that we've not necessarily made a huge mistake and that
there's hopefully a solution
.
Putting a restriction on the bath HW supply and remving all other
restrictions is the way forward. 15mm pipe is not a restriction unless
kinked.
I take it that a restriction reduces the flow rate to the bath (in
this case) if the unrestricted shower is turned on, leaving more for
the shower. Will a restriction reduce the flow rate to the bath when
no other hot taps are on?
If not then that definitely sounds good to me.
Thanks.