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flow and return

Return flow is surface and subsurface water that leaves the field following application of irrigation water. While irrigation return flows are point sources, in the United States they are expressly exempted from discharge permit requirements under the Clean Water Act.Return flows generally return to the irrigation centre after a period of about three to four weeks; due to this, the farmers usually need to pour bleach into the water to clean it of any organisms that have entered the stream. If this is not taken care of, diseases such as typhoid or cholera could enter the irrigation and pose a risk of epidemic disease to surrounding towns and cities.
The return flows in irrigation is nearly 50% of the water supplied in silty clay soil type in tropical countries. The salinity of the return flow water increases with decrease in % of return flow quantity. Rest of the water supplied to irrigation evaporates to atmosphere due to evapotranspiration.
When ground water is extracted for irrigation and other uses, most of the return flows seep back into the ground instead of joining the nearby surface stream. When ground water is used in excess of recharge from rainfall/precipitation, the quality of groundwater deteriorates over a period of time and becomes unfit for irrigation use.

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  1. Ant0912

    Flow & Return firebird C26 combi oil boiler

    Hi, can anyone tell me which pipes are flow and return please. I removed old leaking 2008 C26 firebird oil boiler in June . We have now completed damp proofing works & I need to extend these 4 pipes to go through the wall and into a new boiler room. This area will then be stud wall and...
  2. C

    Cut flow and return pipes

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  3. H

    How to best measure flow and return from boiler?

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  4. Robjolla

    Tee off primary Flow and Return

    Hi new to the forum here and after some advise please. I have done a garage extension and need heating in the room. I am in a town house with no Rads on the ground floor. (Underfloor heating). My boiler (not combi) is downstairs, but megaflow tank is upstairs along with rads upstairs. I have...
  5. F

    Pipe sizing - Replacing a one pipe system with flow and return

    Hi, I'm a first time poster with a skill set akin to that of a competent DIY'er I guess. I'm planning on replacing a old in efficient one pipe system with a flow and return. This will be done on our recently purchased bungalow which has an oil fired boiler. Whilst I'm confident a 22mm flow and...
  6. M

    Effect of pipe sizing in heating system

    Current system Danesmoor utility installed in outbuilding. Flow/return connections on the boiler are each 1.5" BSP then straight into 32mm copper for a run underground of approx. 20m to the house. Main pump at boiler is UPS 25-55. Proposal is to replace old boiler with Hounsfield Tuscan 26/30...
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  7. T

    flow and return for radiator

    Hello, I have a Worcester Greenslave 12/18, and I am about to change a radiator. At the moment the rad is fed by the same pipe, the feed I think, but as the return pipe runs right next to it, can I plumb the rad into the flow and return without causing problems for myself? Will this work, or...
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  8. S

    Max distance for 10mm tails off 22mm flow and return

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  9. H

    Lowering return temperatures

    Evening all. Enthusiastic have a go guy here! I did get into the whole calculation of heat capacity of flow and calculated resistance after we had a few terrifying quotes when I bought the house - Quite a large 3 floor 7 bed Edwardian house. I fitted a 300 litre unvented cylinder and...
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  10. B

    15mm flow and return, plate exchanger blockage?

    The combi boiler has 22mm flow and return outlets but they are immediately reduced to 15mm as they come out the boiler. After the pipes come out of the boiler, they split off into 3 branches. Branch 1 is for a single radiator only. Branch 2 feeds about 9000BTU diownstairs and branch 3 feeds...
  11. R

    Connecting flow and return on radiators

    Hello I have been told that I can connect a new radiator circuit to the pipe work in the airing cupboard. I guess the flow can be teed off below the zone valve? Where do you pick up the return from? It’s a s plan system and in this forum I have heard about the last tee. Is this where the pipe at...
  12. A

    Flow and return the wrong way around

    I would really appreciate your view on this underfloor heating set-up. I’m experiencing what sounds like a knocking noise from the manifold/pipework (can’t tell which) for a few seconds whenever the underfloor heating zones are switched on, so am wondering if it’s an issue with a valve or...
  13. Mark Garland

    Hot flow and return pipes, hot upstairs rad but cold rads downstairs

    As in the title, the flow and return pipes both get hot when the heating is turned on, yet only the upstairs radiators get hot. I am very puzzled by this. Even turning off all thermostatic valves upstairs, none of the downstairs rads get hot. Our plumber says there must be a blockage looking...
  14. R

    Combi boiler using old central heating flow and return

    Hi all, Just a quick question that I have so far received mixed views on. I currently have a vented central heating system, which I plan to have replaced with a combi boiler in the garage. In order to link up with the existing network, one plumber suggested sending the cold water from the...
  15. Inverness

    advise on flow and return points unvented cylinder compared to the height of the header tank

    Hi guys, before I go ahead and install a indirect cylinder. The problem is in the loft where the flow and return points on the cylinder are similar height less than 0.1 bar to the header tank. I'm worried about there might not be enough head from the top of header tank to the flow going into...
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  16. A

    Flow and return in airing cupboard.

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  17. L

    New towel radiator fitting

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  18. C

    Positioning flow and return pipes for a pumped system

    Hi. Does it matter if the return pipe sits above the flow pipe? Its a two pipe system. Sorry if this is a basic question. I am a propper novice.
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  19. A

    Conflicting advice on flow and return for new install

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  20. J

    bleeding flow and return from boiler to UFH manifold!!

    Hi, I have just installed my Underfloor heating. 4 zones in total and pressure tested after filling each loop. I have now connected up to the 22mm flow and 22mm return (new install where the plumber who installed a new boiler left these ready for me). The current system have a radiator curcuit...
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