Hire the best Gas Fitter

Davey pressure pump and pressure tank

Results 1 to 16 of 16
  1. #1
    Senior Member
    Join Date
    Aug 2011
    Location
    Chum Ck, Yarra Valley, Victoria
    Posts
    104

    Default Davey pressure pump and pressure tank

    I have a Davey HM160-15t Torrium 2 which is used to supply water to our house and garden from a 90,000L tank. The largish pump size was recommended as we are in bushfire prone area, and may need to have flow for a number of fire hose reels that are spread around the house surrounds.

    To reduce the number of pump start-ups in low volume water usage situations, I'm considering adding a Davey Supercell pressure tank. However, the manual indicates the tank size maximum is 20L. Is that large enough to make a worthwhile difference for those occasions when those low volume water needs (e.g., hand washing, toilet cisterns, etc) are all that's required?

    Does a 20L pressure tank mean that the pump won't kick until you've used around 20L?

  2. #2
    Golden Member
    Join Date
    Oct 2017
    Location
    Melbourne - Yarra Ranges
    Posts
    713

    Default

    ...not sure on the answer Does a 20L pressure tank mean that the pump won't kick until you've used around 20L? , but assume yes. A spec sheet may provide you with the answer.

    If the above is true, than yes 20l will be more than enough. A modern toilet flush is ~3 to 9 liters and washing your hands, unless its using a fire hose outlet is likely to be less than 1 to 5 liters


    The other alternative is if you have a hill, you could set up a 5,000L header tank using solar (if you have it) to pump up every few days.....obviously a lot more $ investment required.

  3. #3
    4K Club Member Marc's Avatar
    Join Date
    Jul 2003
    Location
    Sydney
    Posts
    13,859

    Default

    If your pump has an electronic pressure switch to start and stop, that is precisely what it is intended to do. That replaces the old pressure tank

    Adding a pressure tank should reduce the start and stop but it may interfere with the way the controller is meant to work. Ask your local pump supplier.

    I have an old pump with no controller, just a pressure switch and a 20L tank. If it means anything, the pump will kick in after about 5 litres have come out the tap. May be 10 but no more.
    As far as I know, I could have a larger pressure tank and bigger is better. However, if you have a controller, I don't know why they say limited to 20L THere must be a reason. I could go as far as 50L no problem ... only problem is the cost.

    PS
    Actually, now that I think about it ... ... the bigger the tank, the longer the time before it kicks in, but also the longer the pump will stay engaged to fill the tank back. Pumps have a limited time they can be on, so perhaps that is the limitation. Continuous duty is usually not more than 10 minutes.
    “It is not necessary to accept everything as true, one must only accept it as necessary”
    Franz Kafka

  4. #4
    Seasoned DIY droog's Avatar
    Join Date
    Sep 2005
    Location
    Bendigo
    Age
    57
    Posts
    2,636

    Default

    Quote Originally Posted by hemp View Post
    I have a Davey HM160-15t Torrium 2 which is used to supply water to our house and garden from a 90,000L tank. The largish pump size was recommended as we are in bushfire prone area, and may need to have flow for a number of fire hose reels that are spread around the house surrounds.

    To reduce the number of pump start-ups in low volume water usage situations, I'm considering adding a Davey Supercell pressure tank. However, the manual indicates the tank size maximum is 20L. Is that large enough to make a worthwhile difference for those occasions when those low volume water needs (e.g., hand washing, toilet cisterns, etc) are all that's required?

    Does a 20L pressure tank mean that the pump won't kick until you've used around 20L?

    A 20l pressure tank is 20 litre in volume but that includes both water and the air above it to allow compression (water does not compress). It will require less than 20l of draw off before the pump starts, for Davey they provide the estimated draw off but this is also dependant on the settings of the pressure switch for the pump.
    https://www.daveywater.com/au/produc...pressure-tanks
    Look for the table "HYDRAULIC PERFORMANCE – NOMINAL DRAW OFF IN LITRES"

  5. #5
    4K Club Member Marc's Avatar
    Join Date
    Jul 2003
    Location
    Sydney
    Posts
    13,859

    Default

    Droog, do you know if a electronically controlled pump can have a pressure tank added on? I think that is the main issue, not so much the size of the tank. I have no experience with controllers. You are right about the bladder volume that would take 1/3 of the tank capacity, also, the cycling time will depend from the pressure in the bladder.

    Where is John when you need him?
    “It is not necessary to accept everything as true, one must only accept it as necessary”
    Franz Kafka

  6. #6
    Seasoned DIY droog's Avatar
    Join Date
    Sep 2005
    Location
    Bendigo
    Age
    57
    Posts
    2,636

    Default

    Quote Originally Posted by Marc View Post
    Droog, do you know if a electronically controlled pump can have a pressure tank added on? I think that is the main issue, not so much the size of the tank. I have no experience with controllers. You are right about the bladder volume that would take 1/3 of the tank capacity, also, the cycling time will depend from the pressure in the bladder
    I don’t see why not, the electronic controllers still have a pressure accumulator just a lot smaller and spring loaded, they cut out at a preset pressure and cut in when that pressure drops below a certain point. I fitted one to a pump without issues although it was only for a garden supply and did not have the amount of cycling of a whole house system.

  7. #7
    4K Club Member
    Join Date
    Jan 2014
    Location
    Kangaroo Island
    Posts
    4,414

    Default

    Quote Originally Posted by Marc View Post
    Where is John when you need him?
    All of the booster pumps I have ever owned work perfectly fine without a pressure tank. They do not cycle on and off; they run as long as a tap is on, even when a trickle. However when a pressure tank is part of the system some special things happen: 1. the pump cycles on and off as the pressure tank fills and empties, maybe twenty times or more during a shower for example; 2. the water pressure at the tap and the flow rate goes up and down substantially as the pressure goes up and down because of the pressure tank filling up and emptying; and 3. the pressure tank fails in a few years and is thrown on the pile of failed pressure tanks somewhere near the tank and/or the pump (in rural areas at least).
    Before you speak, ask yourself: Is it necessary, it is true, does it improve on the silence? - Baba

  8. #8
    4K Club Member Marc's Avatar
    Join Date
    Jul 2003
    Location
    Sydney
    Posts
    13,859

    Default

    Yes, I remember you being a critic of pressure tanks. My experience, limited to just one pump is different. This is a 20 years old pump that is on it's second pressure tank and still the same pressure switch. No pile of old tanks here. Plus for a bit extra I could buy a plastic tank that would outlast the pump.
    Yet the controller if reliable, has some advantages. I believe it is soft start so the stop and start are not as dramatic as in the case of pressure switch. Still, will an electronic controller last 20 years without failing? If you had experience with several pumps, is it because they failed and needed replacing?
    “It is not necessary to accept everything as true, one must only accept it as necessary”
    Franz Kafka

  9. #9
    4K Club Member
    Join Date
    Jan 2014
    Location
    Kangaroo Island
    Posts
    4,414

    Default

    Quote Originally Posted by Marc View Post
    Still, will an electronic controller last 20 years without failing? If you had experience with several pumps, is it because they failed and needed replacing?
    I've only ever bought one new pump, all the others are ones I have 'inherited' as part of a property purchase, or bought secondhand. I have repaired a couple of pressure switches that failed because of a <$1 capacitor inside. The one pump I bought new, for the main house supply, has a DC motor with proportional flow control making it an energy efficient, constant pressure pump. With it the internal plumbing performs better than being connected to mains water, because there is no long pressure dropping pipe from the street feeding into the plumbing. I have seperate pumps for the garden, well, fire pumps, etc because they are all different water sources.

    I remember from the 1960s when my grandfather moved into a new house the pump with pressure bladder used to cycle on and off as the bladder filled and emptied. This had the annoying effect of causing the water in the shower to run hot and cold, as the hot water was gravity feed from a cistern, but the cold was fed directly from the pressure pump and bladder.

    I've lived and worked in a lot of rural places. The water supply in houses with pressure tanks alway performs worse than those without IMHO. Bladders are usually the point of failure, not the bladder tank per se. The stressing of the pump motor is the same at switch-on irrespective of whether a bladder is used or not, but with a bladder the amount of cycling of the pump motor increases, in fact probably more than doubles, so I don't know how that is supposed to make the pump motor last longer. It's usually the pump bearings that give out, seals that start leaking or a failure of a cheap electronic component in the pump controller that ends the service life of a pump, not the motor.

    On farms and station properties discarded pressure tanks are all over the place like discarded beer bottles. Living remotely off grid with no mains water, things that fail are an luxury I am happy to live without, especially when they detract from utility, not add to it.
    Before you speak, ask yourself: Is it necessary, it is true, does it improve on the silence? - Baba

  10. #10
    4K Club Member Marc's Avatar
    Join Date
    Jul 2003
    Location
    Sydney
    Posts
    13,859

    Default

    Haha, yes, I remember your comments on this topic.
    I don't experience any variations in pressure in the shower, unless someone else opens a tap full blast.
    But anyway, I can see your point.
    I am looking to buy a new pump since I believe I have pushed my luck enough.
    Looking for a grundfos 50L/h + but not sure which one.
    They offer such avast variety of pumps that it is mind boggling.
    Multistage , Multistage self priming and Variable speed, each category with many variations. https://justwaterpumps.com.au/grundfos-pumps/

    Sorry Hemp for the hijack.
    “It is not necessary to accept everything as true, one must only accept it as necessary”
    Franz Kafka

  11. #11
    4K Club Member
    Join Date
    Jan 2014
    Location
    Kangaroo Island
    Posts
    4,414

    Default

    The best thing is to get advice from a reputable dealer. The one pump I've bought is a Grundfos Scala2, which I bought mainly because of its low energy consumption. It's a good pump with settable pressure, pipe burst and leak protection (so tanks aren't emptied out if something in the plumbing fails). The 'list' price is ~$1200, but the 'street' price is ~$600! I am reluctant to recommend it though, because the pump failed with a weeping seal and I had it replaced under warranty. Grundfos are meant to be the Rolls Royce of pumps, so that was a bit disappointing.
    Before you speak, ask yourself: Is it necessary, it is true, does it improve on the silence? - Baba

  12. #12
    Senior Member
    Join Date
    Aug 2011
    Location
    Chum Ck, Yarra Valley, Victoria
    Posts
    104

    Default

    Thanks for all the responses.

    Given that putting a pressure pump inline would take some rejigging, and that doing so would not reduce the number of starts per day of the pump, I've decided that it ain't broke ...

  13. #13
    Community Moderator phild01's Avatar
    Join Date
    Aug 2009
    Location
    Sydney, north
    Posts
    16,178

    Default

    Hi hemp, please change your profile location to be more specific, state level as a minimum. It helps for advice (regs, services, products etc).

  14. #14
    Senior Member
    Join Date
    Oct 2009
    Location
    Murrumbateman, NSW, Australia
    Posts
    110

    Default

    I put one of the Davey Dyna Drive DD90 pumps in for our Garden system and boy does it push some water out. You can hear it spool up as you keep turning taps on. It also adjustable pressure output and if your really keen, start staking them up in Parallel for even more output.

    I was so impressed I put one on the house as well. We now have very little change in flow or pressure if your in the shower and someone else flushes the bog or turns a tap on.

    Dave.

  15. #15
    Senior Member
    Join Date
    Nov 2014
    Location
    Sydney
    Posts
    288

    Default

    dmac: Any chance you could provide a clue as to how much the one you use in your house cost?

    Thanks.

  16. #16
    Senior Member
    Join Date
    Oct 2009
    Location
    Murrumbateman, NSW, Australia
    Posts
    110

    Default

    Sent you a pm.

Similar Threads

  1. Replies: 7
    Last Post: 13th Aug 2012, 02:40 PM
  2. header tank to pressure pump conversion
    By gottaoutlaw in forum Plumbing
    Replies: 2
    Last Post: 9th Oct 2010, 01:23 PM
  3. pressure pump question please
    By masterblaster in forum Plumbing
    Replies: 4
    Last Post: 21st Aug 2006, 09:21 PM
  4. tank water pressure pump question please
    By masterblaster in forum Plumbing
    Replies: 7
    Last Post: 28th Jul 2006, 09:14 PM
  5. Pressure Pump - pressure switch setting?
    By Woody Allan in forum Plumbing
    Replies: 4
    Last Post: 4th Jan 2006, 04:12 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •