How to Calculate Feet of Head...???

[Sherra]

OK, I did a little more reading on those sites you linked, and it looks like my maximum flow rate is going to be about 42 GPM anyway because I've got 1.5" PVC pipe, so it looks like even assuming I could be running at my max flow rate I'm going to need to increase the length of time my pump is running... Thanks for the info!

[mas985]

From your pictures, it looks like you have separate runs for suction and return which means you will have 1/3 of the total flow in each run. This is a good thing for 1.5" piping which is pretty small. So three runs of 1.5" pipe is close to the same loss as 1 run of 2.5" pipe.

Given that you are running your pump, what is the filter PSI? Multiply this by 2.31 to get return head. Suction head you can estimate from the web site and it should be fairly accurate. However, my guess is you probably have about 10' of suction head give the pool configuration.

Also, the 42 GPM is the maximum "suggested" flow rate for a single pipe and probably not what you may actually have. To get the flow rate, you must determine the head of your plumbing and look up the flow rate from your pump curves. This value could be well over 42 GPM. But since you have three pipes, you can go much higher.

[Sherra]

I believe I've only got one return line leading from the filter which then "t's" off at the returns. That's the way it looks from the pictures I didn't put on my Yahoo site anyway. I'm guessing their logic on that is because you're less likely to get a clog in a return line??

My pressure reads about 15-17 right after backwashing.

[mas985]

The loss between the filter and the tee is small compared to the loss over long lengths of pipe and through other fittings. Their design is fine and some perfer that over the single large pipe. Either way, the loss is nearly the same so I would not concern myself with that.

With that PSI setting, you have about 47 feet of head in your pool using 10 feet for the suction head. Now look at your pump curve in your manual to determine the flow rate.