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# Monoflow w/ 2 parallel elements connected?

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Member Posts: 131
Am I correct in saying that unless there is a valve/restriction on emitter #1, no flow will occur through emitter #2 under normal open pipe conditions due to pressure drop at #1.

• Member Posts: 23,650
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Not quite. If it is piped more or less as drawn, there will be much less flow through no. 2 than no. 1 -- but there will be some. The flow will split so that the head loss due to flow will be equal in the two paths.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
• Member Posts: 131
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If distance between the two emitters is not equal, do we assume fractional flow in proportion to distance, or still split equally.
• Member Posts: 2,808
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I’d say more equally. The difference would be marginal.
Steve Minnich
• Member Posts: 23,650
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wcs5050 said:

If distance between the two emitters is not equal, do we assume fractional flow in proportion to distance, or still split equally.

It depends on head loss, not distance directly. Head loss is a non-linear function of flow velocity, and thus of pipe sizes and type, as well as all the fittings -- including the size of the emitters. To take a ridiculous example, suppose those connecting pipes were 4 inch copper, and the emitters were half inch -- the flows would be within a whisker of being equal. Then suppose the other way around -- emitter number 2 would get much less.

You can't eyeball it. You have to figure it out.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
• Member Posts: 11,108
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Are both tees of the diverter design?
• Member Posts: 2,646
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If you only have one diverter tee setup and you want two emitters, the best way is reverse return the two emitters.

But with those short distances it may not be necessary. I'd do it reverse return, then you are guaranteed equal flow.
Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
• Member Posts: 131
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Each tee on main run is monoflow/diversion type, correctly oriented upstream and downstream as required.
• Member Posts: 11,108
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If there is lack of flow for these, perhaps the simplest thing would be to install a metering valve between the tees.