Which Mains booster pump

Discussion in 'Plumbers' Talk' started by baracus, Aug 6, 2018.

  1. baracus

    baracus Member


    As part of the whole house refurb I am having a unvented tank ( telford horizonal) system installed. The plumbers have told me to research mains pressure boosters in case the flow rate isnt enough for me. They are allowing for it to be easily added later.

    I have a 32mm pipe coming into the house but it is smaller going to the tap in the street. There are 3 bathrooms all have a 15mm shower head input pipe.

    Do you have any recommendations of a booster than would enhance the showers and what should I look for in terms of the specification of a pump?

    Thanks in advance
  2. rogerk101

    rogerk101 Screwfix Select

    This doesn't make sense. If the flow rate isn't enough, installing a mains pressure booster on your side of the water meter isn't going to make a jot of difference.
    The flow that is available at the street is the flow that is available to your home. If that flow isn't enough for your needs, then you'll have to store enough water in/on your property so that there is enough flow when you need it. Then, and only then, does it make sense to install a main pressure booster.
    What is your available flow rate at the street, and at what pressure?
  3. The Teach

    The Teach Screwfix Select

    What are the water pressure & flow measurements your visiting plumber would have measured them prior to mentioning an unvented cylinder.
    try to avoid having a horizontal cylinder,performance & ongoing cost reasons can be an issue :(
  4. baracus

    baracus Member

    If a mains pressure booster wont affect the flow then what is it used for?
  5. jonathanc

    jonathanc Screwfix Select

    maybe the hint is in the name - pressure?
  6. rogerk101

    rogerk101 Screwfix Select

    It'll only be useful if you have a large quantity of stored water.

    If the mains flow rate from your water provider is x litres per minute, no amount of increased pressure on your property is going to deliver more water than what the water provider is able to supply. If you need a higher flow rate, then you need to store enough water to give you the flow rate you need for the duration you need and at the pressure you need such that your needs have been met by the time your stored water is depleted and the mains water feed can then catch back up again.

    If your plumber hasn't been able to explain this to you, then you should be looking for a better plumber.
  7. The Teach

    The Teach Screwfix Select

    what is the size of the tapping into the water main ? Currently getting a water main tapped to a larger diameter for a customer with poor water flow & volume although their pipework is more than adequate. costing them £2k plus (London price) :p
  8. Allsorts

    Allsorts Super Member

    BA, when you say the 32mm MDPE going to the street goes smaller at the street tap, do you mean down to 25mm or so? In which case, that ain't the root of your problem.

    A simply 'mains booster pump' isn;t going to give you what you want as these can only pump at the max rate of 12lpm.

    I suspect your plumber actually meant a 'mains booster unit' which combines a pump with a water accumulator.

    I can tell you that the Grundfos 3bar unit works an absolute treat and this will give you a phenomenal flow rate at 3 bar (you can even get 4.5 bar versions...). My bro has just had one of these fitted and it's too powerful for his small flat - the shower is 'painful'... - so he's going to have to fit a PRV on the unit's outlet...

    These are around £1200 at the moment, and fitting them is a doddle.

    Also check out the Challis CB+ range - I was quite taken by them, but the plumber my bro found would only fit Grundfos (no regrets, though.) Stuart-Turner also make a version. (Both are also cheaper than the Grund).

    If you are pushed for space, they can be fitted out of the way - a garage is ideal - or even in an purpose-built outside 'box'.

    Jobbie absolutely jobbed.
  9. baracus

    baracus Member

    You could be right Allsorts, he has refereed to this DAB one as an option;

    is that a pump and accumulator?
  10. Allsorts

    Allsorts Super Member

    No, not as it stands. That's effectively a mains booster pump, so is limited to 12 lpm max - and that's pretty pants.

    The only way to ensure and improved flow and pressure is to fit one that has an accumulator as well. That DAB can do it, but it needs that tank:

    In this model, the tank fills from the mains and this is then pumped to the house. You'd need to confirm the max flow rate it could provide - you really want approaching 20 lpm+ for a good thermostatic shower (don't forget the 12 lpm mentioned before has to be shared between the hot and cold).

    I like the Challis because what it does is to pump the mains in to a pressurised vessel which has a rubber diaphragm like a boiler's expansion vessel. This means you have 250-odd litres of water stored at 3 bar - that will blow anyone's socks off :)


    I think these are around the £900 mark - that's good for a complete pump & store system.
  11. baracus

    baracus Member

    Thanks for the explanation and recommendation, much appreciated.
    Allsorts likes this.
  12. The Teach

    The Teach Screwfix Select

    electric pumps have at atleast 1 disadvantage,either fresh water or shytte pumpers.

    think about it.
  13. Allsorts

    Allsorts Super Member

    I don't understand what you're saying, t'Teach?

    The idea with these units is that it'll fill - under pressure - a sizeable accumulator with mains water, ready to be supplied to the house at a terrific rate. Yes, the max the pump can draw from the mains is 12 lpm, but that's enough to recharge the tank fairly quickly. In the unlikely event that you drain the whole tank, then it'll still supply you at that minimum 12 lpm - so it never stops.

    Also, some of these models (eg the Challis and Grundfos) are ok for drinking water as they are sealed from the air and behave effectively like a very large piece of water pipe. Usually, tho', you have a separate pipe straight from the mains to the kitchen tap, by-passing the booster unit.

    If BA's low flow is down to the supply pipe to his house, then that's clearly what to fix. Many properties, however, suffer from a deliberately-reduced mains pressure and, for this, these units are a perfect fix.

    They do work.

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