Ask a plumber/heating ‘engineer’ anything

[OutInTheShed]

Trustmeimadoctor said:

RustyMX5 said:

This one might be a head scratcher but I'll give it a punt.

4 bedroom 2 storey house on multiple levels (rear rooms are higher than the front rooms).

1 x shower room with toilet
1 x shower room
1 x bathroom
2 x toilet rooms

Because there isn't enough space in the loft for tanks there's a plant / utility room at floor 1 1/4 (the level at the rear of the ground level). The utility room contains a freezer, washing machine, 245 litre unvented hot water tank, a boiler, a water softener, 227 litre cold water tank and a Grundfos Scala II pump which pushes the cold water around the house.

My main issues are as follows:

The Grundfos pump, although it does a great job is bloody noisy.
The 227 litre cold tank is absolutely massive and I'd rather something smaller so I can use the sockets behind it for a tumble dryer or something else.

When I specced it with the plumber I went with no loss of pressure across any of the showers if they are running at the same time. The reality is that I probably went too high on the spec and the plumber delivered a solution which would deliver against that.

So what options are available to either do away with the tank / pump or just the tank?

do you mean pressure or flow rate, id assume flow rate.

how much do you want in lpm from each shower

The answer might depend on what the mains will deliver in terms of litres per minute into various pressures.
The trouble is, you can't expect a guaranteed supply pressure 100% of the time.
With decent thermostatic shower mixers, you should be able to accept a bit of pressure variation, it should not be like electric showers where the temperature is directly coupled to flow rate or fiddly mixers wich scald you if someone flushes a loo.

The rest of it depends what you want in terms of flow rate.
How badly do you want a powerful shower?
Personally we can run two showers which we find adequate without a pump.
It did involve choosing a suitable mixer and sprayhead and avoiding restrictive adaptors.

[Trustmeimadoctor]

Oh I agree but we need to establish what they actually want first
Even if the mains can't supply it you could use a buffer if you really need 45lpm for some reason

[Actual]

Trustmeimadoctor said:

people never listen when i say you dont need huge l/min for a shower

and you cetainly dont need it for a tap on a sink so get a 3lpm flow reducer in them

my shower is 5.4l/min is absolutely fine one issue is you cant just restrict any shower down and it be fine if its too big or the holes too big you do notice it but a well designed low flow head isnt hugely noticeable

fk that.

Moved to this house and the bathroom taps had a flow rate of 3.5L/min. I measured.

It took about 5 minutes for the hot to run hot let alone fill the basin.

Installed a mixer tap and specially chose one from Screwfix which was NOT labelled "Saving water at home" and now I get a glorious 17L/min.