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  1. #1
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    Default Need pump advice

    Hello people,
    I have installed a 10 000 litre tank & thought that I could get away with gravity to get the H2O where I wanted it. It kinda does, but I think it's time to hook a pump into the system, Only going to use for the garden & maybe to supply water to a large evaporative cooler that cools the shed. It's a long skinny block 60m x 20m on a bit of a slope. I have run 1 1/2" poly from to tank (which is up the back & on the highest part of the block) down along the backyard & house to the front yard. I want to install an automatic pump that will cope with the aircon float valve & power 4 taps for the garden. My question is - do I need a pump with a pressure tank? DAB pumps have some pretty good deals on at the moment but I'm finding the range a little confusing. Are there any pump gurus out there that can advise?
    Cheers!!

  2. #2
    Heavy Machinery Claw Hama's Avatar
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    Hi Boarder Boy, who did you buy the tank and poly pipe from, can they give you any advice. I think it would be sized on the number of taps you might have on at any one time ie evap cooler (which only uses a trickle while the unit is running) and a hose in the garden. And what pressure you want out of these outlets. I'd just phone and ask a couple of irigation suppliers.
    A good edge takes a little sweat!!

  3. #3
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    Thanks for the reply Claw,
    tank was purchased from one supplier, pipe from another, figured I could use gravity, but it sucks - as we all know - not quite hard enough - hence the pump. I'm sure I could get advice from any number of pump shops, but they would be pushing their brand. I was thinking that with the pump I could run 3-4 taps, feeding drip irrigation zones, at once. I realise that the cooler is just a trickle, but would it cause dramas with a non pressure tank fitted auto tank? ie. cause the pump to turn on & off quickly? I was hoping for some unbiased info.
    Cheers.

  4. #4
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    I purchased a no-name pump from Nightingale Electrics here in Melbourne. They import them by the container load from China. For $195 I got a 1.1hp pressure pump (No tank but they do sell a model with it for $250-odd), does 45 l/min, stainless impeller/housing and and an auto-controler. I only needed to run 3/4 poly to the front of my house, around 45metres and it will run the 9 pop-up lawn sprinklers and all garden beds with ease. The way I see it, it's 1/3 price of a Davey or Onga and does the same job. If it dies in a year or two, I buy another and keep the dud for replacement parts. You could possibly go a larger model but if it's only drip systems it would be fine.

  5. #5
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    Default

    Thanks for that BMD
    Cheers

  6. #6
    Senior Member totoblue's Avatar
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    Default

    In my experience, you need bugger all pressure to run drippers. Our tank when almost empty will run continuous drip hose (with a head of about 60cm).

    We have a QB60 chinese pump (1/2 hp) which is plenty for a single tap. This was about $60 delivered from Grays Online a couple of years ago. There are plenty on ebay and they now seem to be going for about $20-odd plus delivery. Lots of other pumps there too, including Chinese pumps with pressure tanks and also brand-name pumps.

    IMHO you will need a pressure tank so that the pump is not always cycling for the evap cooler, plus you only need to turn on the tap to get water. Our pump has no auto switch or pressure tank so I have it set up with a wireless remote control (about $60 from Bunnings).

    Our pump is plumbed with 19mm poly pipe. Bloody difficult to remove every last drip from the poly pipe (even just with the pressure from the tank head). I used those 19mm poly taps initially and then tried in-line brass taps with 19mm barb to BSP fittings. Some brands leak - I have been told that there are different grades of 19mm poly and you need to use fittings appropriate for the grade of poly you are using. Ended up with brass garden taps screwed into galv risers so the tap is firmly mounted. Still the odd drop here and there so I turn off the water at the tank. I also run the pump from the outlet on the tank about 60cm above the bottom of the tank (to get cleaner water).

    If I was doing it again, I'd use mains-grade pex pipe, and have a pressure tank and switch and forget the remote.

  7. #7
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    Default

    Thanks for the info re pressure tank - I thought that may be the case. I'll definitely be going for an auto pump, turn on a tap & away she goes.
    It is very confusing when buying fittings etc for the different grades & sizes of poly pipe that's out there.
    Ag Vs domestic Vs metric etc. Our tank is hooked into 1 1/2" Ag poly, which seemed to be a cheap way to go Off takes from the large 1 1/2" pipe are those saddle clamp type fittings that require a hole to be drilled into the main pipe - again a much cheaper option than large "T" fittings. It will probably leak a little but these fittings are in the garden anyway so I'm not too worried about small leaks. I guess now I'll be after more adapters to hook a pump into the system.
    Cheers!!

  8. #8
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    I Installed a little Bianco pump off my mates water tank down in Goulburn when we built his amenities shed and kitchen on his farm. It cost around the $300 mark and works off a pressure switch set at a pre-determined pressure (450kPa from memory) meaning the system is charged at that pressure and as soon as there is a drop of 50kPa or more (when a tap is turned on or the toilet flushed etc) it cuts in supplying ample pressure, its running a toilet, shower, laundry tub, washing machine,hose cock, kitchen sink aswell as a 50L HWS, not all at once obviously!
    Fed off a 1" feed from the tank with a by-pass incase the pump needs to be removed for servicing it works a treat.
    http://http://www.pumpshop.com.au/co...roduct-b24-u24
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  9. #9
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    Thanks wonderplumb & all.
    I think I'm set to go shopping. Pump with auto pressure switch & pressure tank 1/2 - 3/4 hp.
    totoblue - pump outlet at 60cm above bottom of tank? - that's a fair amount of water that you can't access. I put in a 130 litre first flush diverter that means that the water that I'm collecting is very clean, outlet 20cm from tank bottom.
    Cheers all.

  10. #10
    Apprentice (new member) Lost_The_Plot's Avatar
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    Border boy,
    If your looking for good pumps and dont want to spend too, much. Look at Grundfos, Vada, Flyght.

    STAY AWAY from Davey. I work for Reece and all i can say is they are NASTY pumps. Davey has
    poor service, and a high failure rate.
    Oh and make sure you cover your pump most pump manufacturers will not warrent pumps left to the
    weather.
    Hope this isn't too late.

  11. #11
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    Thanks Lost,
    you're not too late. I looked at a couple of Davey pumps & was scared by the price. I'm surprised by your experiences with them.
    Cover for the pump is on my list.
    Cheers.

  12. #12
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    house i was working in recently was using davey pump over the two weeks i was there the pump bearings got louder and louder when i commented on noise was told by client that this was the third pump from davey in 18 months and wouldnt recommend to anyone

  13. #13
    Tool Whore - 1K Club Member Vernonv's Avatar
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    Maybe the quality of Davey pumps has only fallen in recent years ... we have had a Davey pump on our place for the last 7 years and probably a few years before that (before we owned the house) and have never had a problem with it? Or maybe we just got lucky.
    Cheers.

    Vernon.
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  14. #14
    Senior Member totoblue's Avatar
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    Quote Originally Posted by Border boy View Post
    totoblue - pump outlet at 60cm above bottom of tank? - that's a fair amount of water that you can't access. I put in a 130 litre first flush diverter that means that the water that I'm collecting is very clean, outlet 20cm from tank bottom.
    I did the numbers on first flush diverters and with the rainfall pattern here, I calculated that we'd lose a significant amount of collected rain. I got the rainfall stats from the Met Bureau web site to work it out. It seems to take 1mm of rain to wet our tiled roof before there is any runoff at all.

    There are about 100 days of over 1mm of rain per annum in Melbourne, 46 days with rain that is less than 1mm, and total rainfall of 650mm. If rain days when the total rainfall is less than 1mm have on average 0.5mm of rain then there is an average 6.2 mm of rain per day when the total rainfall is over 1mm (that's days when there has been enough rainfall to wet the roof). So in practice 5.2mm of rain per rain day could be collected.

    According to my calculations, there is 44 sqm flowing into my tank (but according to measurements of rain gauge vs tank level gauge, there is 19 sqm). Hence you can see that if I had a diverter I'd lose significant amounts of rain. An average rain day only produces 5.2 x 19 = 99 litres. Hence a diverter would mean I'd only be collecting on days of heavy rain.

    If I had a bigger tank that might be ok but my tank is only 1200 litres (it is a Waterwall which is slimline and fits down the side of our house).

    I have thought about a rain head screen or "Frogmouth" to filter out the crud - we currently only have the inlet filter on the tank (really all that keeps out is mosquitos, sticks and animals).

    The bottom 60cm of water is accessed by another outlet about 5cm from the bottom, "powered" by gravity - it is plenty of pressure to run a drip hose, although that only works on the front garden (not the back which is higher).

    Edited to fix rain stats - I was using rain days not rain days >= 1mm.
    BoM stats here http://www.bom.gov.au/climate/averag...6071_All.shtml
    Last edited by totoblue; 10th Jun 2008 at 02:12 PM. Reason: fix rain stats - I was using rain days not rain days >= 1mm.

  15. #15
    Tool Whore - 1K Club Member Vernonv's Avatar
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    Toto, do you know why is there such a significant difference between your calculated roof area (44sqm) and gauge vs tank (19sqm) ... that's pretty significant.

    Also I assume you are calculating "flat" roof area and not actual/physical/pitched roof area.
    Cheers.

    Vernon.
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  16. #16
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    I have been playing with my pump for similar, trying to save power.

    The tips I can give you are.
    Mine is a Bianco w/ 2 x tanks (aftermarket) and both an electronic Bianco controller and I'm testing a mechanical controller.

    a) A tank will stop the pump coming on as soon or as often.
    b) ANY flow with the electronic controller will keep the pump running, even a trickle, It won't cycle to save power.
    c) The electronic controller will run for 1min - 3 mins after taps are off with the tanks, as they maintain a small decreasing flow.
    d) The mechanical controller will run for 20-30 secs as the tanks refill
    e) Watch your chinese pumps. Mate is using the cheap cheap motors from them for some other things and the pumps are a really lousy design in my opinion. Impuse type thing, not centrigufal. I haven't pulled my bianco apart, but it looks better than his cast iron ones.
    f) The electronic controllers can't be modifed for pressure, the mechanicals are adjustable.
    g) I wouldn't run a tank + electronic controlller again. Testing mechanical atm.
    h) Electronic cut in pressure is a little low.
    i) Drippers will keep the pump running, pulling 500W+. I would think about a header tank or something.

    I can't compare to an Aussie pump yet.

    Paul

  17. #17
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    Thanks all for your input - I realise more why I posted this thread - bloody hard to know which way to go. me3, how does a mechanical controller work?
    I've been advised by a pump shop guy that the pressure tank systems don't have a run dry safety cutoff provision - not that this is a major worry. I was thinking of just starting with an electronic controller & taking it from there.
    I'm keen to hear about these mechanical controllers.
    Cheers

  18. #18
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    You can buy them on eBay, just an arrangement of springs etc in a box that triggers a switch based on pressure. You can adust the set points on them.

    Paul

  19. #19
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    Thanks me3,
    I'll look into them.
    cheers.

  20. #20
    Senior Member totoblue's Avatar
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    Quote Originally Posted by Vernonv View Post
    Toto, do you know why is there such a significant difference between your calculated roof area (44sqm) and gauge vs tank (19sqm) ... that's pretty significant.

    Also I assume you are calculating "flat" roof area and not actual/physical/pitched roof area.
    Yes I calculated flat roof area.

    There are several reasons why the apparent roof area and the calculated roof area could be different.

    1. the collected roof is on the east side of the house and the prevailing weather is from the west (my neighbour has 4 tanks - two on each side of the house - and he collects less rain on the east side).

    If I did the maths correctly, assuming my roof is pitched at 30 degrees and since it is oriented north south, rain inclined at 45 degrees from the west would increase the collected rain on the west by nearly 60% and decrease it by 60% on the east. If the rain was at 30 degrees from the west, the loss on the east side would be 33%. Even rain at 20 degrees, reduces the east side by 21%.

    Assuming the roof is horizontally 1 unit wide, then the fall is tan(roof slope).
    The east side loss is thus tan(rain angle from vertical) * fall, so the loss on the east side is tan(roof slope) * tan(rain angle from vertical)

    2. There is a long gutter with the downpipe/tank at one end and another downpipe at the other. I eyeballed the high point so it might be out by 10 or 20%.

    3. There is an overflow on the gutter (the gutters are stupidly designed with the back lower than the front - maybe all gutters for tiled roofs are like this due to the thickness of the tiles? - resulting in overflow going into the eaves - so the previous owner has added some overflow pipes a few cm above the bottom of the gutter). The overflow doesn't flow in normal rain but does in heavy rain.

    The time I measured it was not particularly stormy so I think the rain might have been at 20-30 degrees say, There may have been some overflow.

  21. #21
    Tool Whore - 1K Club Member Vernonv's Avatar
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    Hi Toto,
    I'll take your word for it that the maths works out, but your reasoning certainly sounds valid.
    I must admit I assumed you were catching all the water falling on your roof, not just part - as you have already calculated, that will certainly cause issues with the recovered volumes.
    Cheers.

    Vernon.
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