TDH question?

[amin36]

Guys

I want to calculate the TDH of one of my client's pool using a vacuum and pressure gauge on the pool pump to see if we need to change the pump and filter or not.

My question is:

Is this TDS calculation a constant number regardless of changing the pump or does it change if we change the pump?

 

[PoolGate]

Huh?

 

[amin36]

Huh?

How To Measure Total Dynamic Head With Gauges - INYOPools.com

How To Measure Total Dynamic Head With Gauges

www.inyopools.com

 

[JamesW]

Get the pressure gauge readings and convert them into feet of head.

Use this formula to generate a system curve where A is the total feet of head and B is the flow.

Y = A/((B/X)^2)

For example, if A = 50 feet of head and B = 80 gpm, then the graph is below for the system curve.

What pump does the customer have?

Use the pump performance curve to determine the flow from the total head.

If you have a variable speed pump, you can generate a system curve by checking the flow and head at various speeds, which is more accurate than using the formula.

Once you have a system curve, you can plot the pump performance curves on the same graph and find the operating points for the pump or for different speeds.

Is the pump single speed or variable speed?

plot Y = 50/((80/X)^2), yfrom 0 to 100 - Wolfram|Alpha

Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.

www.wolframalpha.com

 

[JamesW]

How to Read Pump & System Curves

If you find yourself somewhat mystified by pump curves and performance charts, or if you need to train someone about hydraulic efficiency, here’s a brief primer to get you started.

www.aquamagazine.com

 

[JamesW]

Below is roughly Curve A.

 

[mas985]

Is this TDS calculation a constant number regardless of changing the pump or does it change if we change the pump?

It changes with the pump, valve settings, RPM changes, almost anything you do to the plumbing will change TDH.

But the real question is why do you need to know TDH. In most cases it total unnecessary.

 

[JamesW]

But the real question is why do you need to know TDH.

They are in the business and maybe they just want to do this on some pools to see what the system curve is.

It’s probably not necessary, but service techs should do it sometimes so that they know how to do it.

I want to calculate the TDH of one of my client's pool using a vacuum and pressure gauge on the pool pump to see if we need to change the pump and filter or not.

@amin36, what pump and filter are currently on the pool?

What issues are you trying to solve?

Can you describe pool, system and plumbing?

 

[amin36]

They are in the business and maybe they just want to do this on some pools to see what the system curve is.

It’s probably not necessary, but service techs should do it sometimes so that they know how to do it.

@amin36, what pump and filter are currently on the pool?

What issues are you trying to solve?

Can you describe pool, system and plumbing?

Thanks mark and james.i really apreciate your support!

Actually i want to calculate the real flow rate of the water to set a proper run time for the water circulation using pump curve.

 

[mas985]

Run time is not really that dependent on flow rate. You might be thinking of the outdated rule of thumb about turnovers. A pool does not need a certain amount of turnovers to be clean. Some pools can do it very quickly while others take longer. It depends more on local conditions rather than flow rates. You might want to read some of the articles in Pool School:

Determine Pump Run Time

To figure out how many hours you need to run your pump, you need to know how fast your pump works. You can find this here.

www.troublefreepool.com

Is the reason that you are asking this question because of an algae problem? This has more to do with chemistry than it does runtime. Again, Pool School can help with maintenance suggestions:

Pool School

www.troublefreepool.com

If you can give us some more details about what is happen, we can point you to the appropriate material.

Also, is this for a residential or public pool?

 

[JamesW]

Actually i want to calculate the real flow rate of the water to set a proper run time for the water circulation using pump curve.

For a residential pool, running continuously at the slowest flow that achieves the purpose is the most efficient option.

All customers should be encouraged to switch to variable speed pumps and run as slow as possible while still skimming or meeting flow requirements for a SWG or heater.

For commercial pools, you have to meet certain turnover rules as per local health code.