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Old 12-03-2013, 07:39 PM
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1idejim 1idejim is offline
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Pressure measurement question

My question is directed toward Boots but any input is welcome.

I'm wondering if installing a pressure gauge downstream of a centrifugal pump on a pool return might lend a clue as to the pumps perfoance. I've always used a vacuum gauge at the pump volutes for evaluations but it dawned on me that we use a pressure gauge on the filter to determine when the filter needs service, why not the pump.

I realize that the pool is a closed system, (meaning the intake and return are from the same resivoure) bit having no bulkheads (lack of a better word) one can only measure dynamic pressure.

Once a pump is in operation and the pressure recorded, the pressure could be compared anytime the pump was running.
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Old 12-05-2013, 08:54 AM
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grassman177 grassman177 is offline
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I guess no one knows
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Old 12-05-2013, 10:10 AM
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I never did place many gauges on field plumbing, because outdoor gauges always died over the winter. They can't fail to be useful as a tell-tale, or a diagnostic aid.
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Old 12-05-2013, 10:23 AM
Kiril Kiril is offline
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Quote:
Originally Posted by 1idejim View Post
My question is directed toward Boots but any input is welcome.

I'm wondering if installing a pressure gauge downstream of a centrifugal pump on a pool return might lend a clue as to the pumps perfoance. I've always used a vacuum gauge at the pump volutes for evaluations but it dawned on me that we use a pressure gauge on the filter to determine when the filter needs service, why not the pump.

I realize that the pool is a closed system, (meaning the intake and return are from the same resivoure) bit having no bulkheads (lack of a better word) one can only measure dynamic pressure.

Once a pump is in operation and the pressure recorded, the pressure could be compared anytime the pump was running.
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What happens to your measurement when demand changes?
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Old 12-05-2013, 03:21 PM
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1idejim 1idejim is offline
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What happens to your measurement when demand changes?
That's a good point Chief. In the pool industry demand would decrease due to constriction or obstruction or increase due to breakage or additional pumps drawing off the return
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Old 12-05-2013, 10:02 PM
stebs stebs is offline
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Jim, unless im misunderstanding you, the gauge on the filter would give you a pressure post pump and yet pre-filter.... To check pump performance, go by clean filter readings, although there are a lot of variables... water level in pool, clean skimmers, clean main drains, all valves in same spot...
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Old 12-05-2013, 10:27 PM
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Originally Posted by stebs View Post
Jim, unless im misunderstanding you, the gauge on the filter would give you a pressure post pump and yet pre-filter.... To check pump performance, go by clean filter readings, although there are a lot of variables... water level in pool, clean skimmers, clean main drains, all valves in same spot...
We've always used the filter pressure as reference point for cleaning the filter. 8-12 psi is optimal clean filter pressure range. 18-20 psi and we clean the filter.

The pressure at the return should be somewhat higher due to the reduction in size of the orfice at the wall
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Old 12-05-2013, 10:51 PM
Kiril Kiril is offline
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Originally Posted by 1idejim View Post
That's a good point Chief. In the pool industry demand would decrease due to constriction or obstruction or increase due to breakage or additional pumps drawing off the return
So a change in pressure may or may not indicate a decrease in pump performance, but it may also indicate other potential problems in the system.
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Old 12-05-2013, 11:02 PM
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So a change in pressure may or may not indicate a decrease in pump performance, but it may also indicate other potential problems in the system.
That's what I'm struggling with. L
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Old 12-05-2013, 11:02 PM
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1idejim 1idejim is offline
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So a change in pressure may or may not indicate a decrease in pump performance, but it may also indicate other potential problems in the system.
That's what I'm struggling with. Looks like some in field experiments are in order.
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