Water flow rate bathtub query

BobbyJoe · Oct 2, 2020

Hi everyone just looking for some advice regarding water flow rate:

Live on 2nd floor flat
Boiler: Vokera Easi heat 25 combi boiler
Water supply: Incoming water for hot and cold water is via the mains water supply
Boiler on kitchen wall is about 10 metres from bathroom

Does this seems about right or normal as I filled a 10 litre bucket of water from the bathtub mixer tap:
Cold water from tap filled 10 litre bucket in 25 seconds
Hot water from tap filled 10 litre bucket in 60 seconds

I have a red gate valve (22mm) which supplies the water to the flat in a high cupboard, to reduce the cold water flow rate is it okay to turn it until the flow rate is lower or should it be left fully open?

I just want to know if the cold and hot water flow rates are normal and if it matters if I reduce the cold water flow rate by turning the red gate valve.

Any information would be really appreciated many thanks.🙂

JCplumb · Oct 2, 2020

That boiler is advertised with a flow rate of 10.2l/minute with a 35deg rise, so the flow is set correctly for that boiler.

Ric2013 · Oct 3, 2020

BobbyJoe said:
I have a red gate valve (22mm) which supplies the water to the flat in a high cupboard, to reduce the cold water flow rate is it okay to turn it until the flow rate is lower or should it be left fully open?

Is this your mains pressure cold water? If so:

I would leave it fully open. What harm would turning it down do though? Not a lot, might eventually wear the valve out, but we're talking years. Might also reduce your hot water flow rate as you are also supplying the boiler through that valve.

If you wanted to reduce the maximum pressure for some reason, a partially shut valve is not the best way; the best way would be a Pressure Reducing Valve.

BobbyJoe · Oct 3, 2020

Thank you so much for the replies, I will just leave the gate valve as it is. I just didn't know that the hot and cold water flow vary and it is normal for hot and cold to have different times when filling a bucket of water.

Ben-gee · Oct 3, 2020

It depends upon the system, the flow rate is not different because one is hot and one is cold , please don’t think that.
In your system; the flow rate is slowed down by the boiler so that it can be heated sufficiently as it passes through on demand - this results inthe hot flow rate being less than the cold.

In a gravity system; both hot and cold are fed from the same tank, the hot is heated and stored for later use- both hot and cold will have the same flow rates.
There are other systems too, but you get the idea.