Single Positive water pump

karltimber

Hi,

have a rain water system installed -diy style.
Feeds ext taps and toilet.
Watermill pump housing broke so need a replacement single positive head on-demand pump.
What power of pump needed for garden/car washing - 1.5 bar + ?

any recommendations ?
these any good - https://www.taps4less.ie/PP/ST-49086-NEW.html


Q - if I got a twin impeller - how could I get this to work on a single line ?

thx

K

John.G

karltimber wrote: »

Hi,

have a rain water system installed -diy style.
Feeds ext taps and toilet.
Watermill pump housing broke so need a replacement single positive head on-demand pump.
What power of pump needed for garden/car washing - 1.5 bar + ?

any recommendations ?
these any good - https://www.taps4less.ie/PP/ST-49086-NEW.html


Q - if I got a twin impeller - how could I get this to work on a single line ?

thx

K

If you require 1,5 Bar (15M) then the above pump's flow rate is 4.8 LPM, if 1 bar (10M) is your minimum accepted pressure then the flow rate is 9.2 LPM.(See the pump curves in your link, above)
You could IMO get a twin impeller (double ended) one but make sure that you have a large diameter line, say 1" supplying both pump suction tails, then T off the two discharges. You should get close to double the flowrates then at the above pump pressures, ie 9.6 LPM @ 1.5 Bar & 18.4 LPM @ 1.0 Bar. ( But make sure to look at this pump; pump curve before buying)

I think they also do a 3.3 Bar (single) head which will give you similar flow rates as "doubling up" above and may not be hugely more expensive. There is a single (brass bodied and much longer lasting) Monsoon as well but its probably 3 times the cost of the plastic bodied one.

karltimber

I have two ibc's with 2000 litres of water, supplied to the pump by 3/4", then into a pump, then onto a filter and then 1/2" pipe afterwards.

Am I better off with an entry level unit ? - https://www.taps4less.ie/PP/ST-46503.html

John.G

karltimber wrote: »

I have two ibc's with 2000 litres of water, supplied to the pump by 3/4", then into a pump, then onto a filter and then 1/2" pipe afterwards.

Am I better off with an entry level unit ? - https://www.taps4less.ie/PP/ST-46503.html

Yes, I think you are better off using the single, one thing to check out is the rating, some shower type pumps are only rated for 30 mins on & 30 mins off (which still might be quite adequate for your requirements) although I didn't see it mentioned in your link above.

karltimber

Thanks John - great info for the pump newbie, will keep an eye on adverts etc and the items you mentioned.

It'll never be on for 30mins a go.taps, toilet, car wash.
Info is power - if something good comes along - twin or single - I know what to check.

thanks again

K

John.G

karltimber wrote: »

Thanks John - great info for the pump newbie, will keep an eye on adverts etc and the items you mentioned.

It'll never be on for 30mins a go.taps, toilet, car wash.
Info is power - if something good comes along - twin or single - I know what to check.

thanks again

K

One other thing there, you say in post No3 that there is a filter on the discharge after the filter, I presume/hope you have some form of coarse filtration on the run off into the IBC's as you don't want any crap getting into the pump suction.

karltimber

All covered - mesh beside the gutter outlet (leaves etc), fine mesh filter to 70microns, with half a chlorine tablet in the middle of the filter.  Then post pump - a charcoal filter to 22 microns removing fine dirt and the chlorine.

karltimber

John.G wrote: »

Yes, I think you are better off using the single, one thing to check out is the rating,

My setup can be changed, as most pumps 2nd hand are dual.
I could attach each ibc to each 3/4 inlet.
But can I have the two outlets attached to a 3/4 T and then reduce to 1/2 after ?

Thx

K

John.G

karltimber wrote: »

My setup can be changed, as most pumps 2nd hand are dual.
I could attach each ibc to each 3/4 inlet.
But can I have the two outlets attached to a 3/4 T and then reduce to 1/2 after ?

Thx

K

I don't see any reason why you can't reduce it to 1/2", the length and ID of the 1/2" will obviously reduce the flow rate compared to a 3/4" but it shouldn't have any detrimental effect on the pump, if you give me some idea of the length of the 1/2" pipe and a reasonably accurate ID of the pipe then I can tell you reasonably accurately what the final head/flow should be.

karltimber

John.G wrote: »

I don't see any reason why you can't reduce it to 1/2", the length and ID of the 1/2" will obviously reduce the flow rate compared to a 3/4" but it shouldn't have any detrimental effect on the pump, if you give me some idea of the length of the 1/2" pipe and a reasonably accurate ID of the pipe then I can tell you reasonably accurately what the final head/flow should be.

Hi, it's a standard 1/2 copper pipe, feeding outside taps and a toilet, i was more concerned with the effect on the pump. If the twin works, I'll go with one of them so.

Thx.