Pressurised system vs vented system and having a pump in the system

leprechaun1916

Hi all,

I am currently in the middle of a new build and was wondering what is the best type of plumbing system to go for.

I would like to have half decent pressure for showers, I will have 2 that will be using water from the hot water tank, I'm going for a solar panels so would like to use this water at a decent pressure for those two showers.

As I see it ( but as always am open to correction) I can go for a pressurised system which seems fine apart from the fact that where I am building there is often full day outages and as there will be no storage tank may leave me short.

I could go for a vented system and place a pump on it in the attic for the system, but I hear these can be noisy. Alternatively I could go for a pump on the wall at each shower and pump it for each shower at the shower.


I am basically interested in peoples experiences with regards use and prices for the systems I mentioned or any alternatives that I may not be aware of. Of course if people were in my shoes what they would do etc

Thanks as ever

sunnysoutheast

We have a fully pressurised system, with a 450l dual coil HW tank (no solar as yet though) and 2 x 300l CW storage tanks in the loft. The pump is a Grundfos MQ. We also put in a temperature reducing valve on the output to prevent scalding.

We've got the pressure set to 2 bar which is fine for us. You can set it higher but that shortens the life of the pump.

The other option is to just have the showers pressurised, with the taps on the vented system.

SSE

Carlow52

OP: as far as I know u must have a cold storage tank as most LA's will not permit a pump on the cold water mains to house.

I have a full pressurised system with a wilo pump on a rubber pad on a concrete floor: it is quite quiet:) if I was doing it again I would take the ensuite toilets off the pump as at 3am u will here the pump

Someone on the forum has a pressurized system where the rising main is used to pressurize the system using an air tank, I think it is dolanbaker

Ging Ging

Pressurised systems can be noisey. Depends on position of pump. Choose carefully (not in hot press next to masterbedroom). Have pump on rubber mat as stated above and take toilets off tank via gravity feed. Theres also pumps available that are small submersibles and fit into the cold water storage tanks, pros of this are sound of pump is insulated by being sussounded by water plus its usually in attic so not in middle of main sleeping area (possibly directly above). A normal pressurising pump system may be able to work as a gravity sytem if you switch the pump off (i.e. only switch on for showers) if theres sufficient head of pressure/tank height. With the submersible this is not the case as the pipe connects to top of tank.

Carlow52

Carlow52 wrote: »

OP: as far as I know u must have a cold storage tank as most LA's will not permit a pump on the cold water mains to house.

I have a full pressurised system with a wilo pump on a rubber pad on a concrete floor: it is quite quiet:) if I was doing it again I would take the ensuite toilets off the pump as at 3am u will here the pump

Someone on the forum has a pressurized system where the rising main is used to pressurize the system using an air tank, I think it is dolanbaker

Yes, what I have is called a "cold water accumulator" it's basically a cylinder with an air filled "balloon" in it which is squeezed by the rising mains water pressure and expands when a tap is turned on.
It increases the flow rate not the pressure of the water, but when using a shower it gives the impression of being a power shower, can easily drive a shower for about 10-15 minutes before the balloon stops expanding/tank empties.

By having it installed on the rising main, the high flow rate is available to all the taps in the house, just don't turn on the tap of the bidet too quickly :eek:

Ging Ging

Hi Dolanbaker. What way do you size the accumulater tank? Is it just the bigger the more capacity and less pump cycling? Yours 100litres? I'm assuming its like a bigger version of the white vessel thats fitted with an unvented dhw cylinder or maybe more like the blue one that goes with a deep well or submersible well pump.

Ging Ging

Ging Ging wrote: »

Hi Dolanbaker. What way do you size the accumulater tank? Is it just the bigger the more capacity and less pump cycling? Yours 100litres? I'm assuming its like a bigger version of the white vessel thats fitted with an unvented dhw cylinder or maybe more like the blue one that goes with a deep well or submersible well pump.

The tank I have is blue and iirc 250litres, it's totally passive there are no active pumps in the system.
The tank is "charged" by mains water pressure only.