Replumbing in-ground Pool

[jason9332]

Greetings,
First, I have a 18x36, in-ground cement pool. 25,000 gallons
I had a valve go bad on my intake line from the skimmer so I'm replumbing things. My question is in regards to those intake lines (1 from the skimmer, 1 from the drain). I'd like to redo that so the valve is 2 feet above ground level (currently they are right as the pipes come out of the ground). My concern is in regards to getting a prime next spring. Should that be an issue? I live in Michigan so I'm preparing to close things now.

I hope I explained that right.
Thanks!

 

[Isaac-1]

You should be ok, although it might be better if you try to stay a little lower, say 18 inches.

 

[duraleigh]

If your circulatory system is airtight, it will make virtually no difference. That said, it is pretty tough to get your system airtight and keep it that way.

So, keeping them lower will make it easier to prime. as you suspect.

 

[GigaMike]

... it is pretty tough to get your system airtight and keep it that way...

Quick question regarding this statement. I am replacing my single speed pump with a 2-speed pump after I close for the winter this year. Right now the single speed loses all of its water every day. Partly due to the fact that air is entering the system with cracks at the pump and a few other loose ends. So every day the pump is empty when the system starts up at noon. It takes about 20-30 seconds and water is flowing just fine (with air though). As I plan on fixing all of the problems with air entering the system, I am worried that I will still loose prime every night when the system turns off. With the two-speed pump being on LOW all the time, am I going to have problems with the pump priming every day? I havent measured all the head but I can tell you the skimmer and MD are each on about 60 feet of 1 1/2" PVC from the pad. FWIW I am looking at a 1hp Pentair two speed on amazon for $450.

Thanks for the reply.

 

[Agent99]

As stated, lower is better for the valve. We have the same size pool and I had mine resurfaced along with all new coping and stamped concrete decking so I had the chance to redo all my plumbing at the pad. I think my valve is around 10-12" above the pool level. I simply matched it to the height of my pump inlet as it sits on the pad.

There are some things you can do to help improve priming. For my IntelliFlo (and I suspect other pumps as well), the manual says to have a straight pipe of 5x the diameter going into the pump. This allows a large volume, smooth flow of water enter the pump. An old hat at Pentair (his words, not mine! ) suggested I bump the size and length of the pipe entering the pump to help priming even more. All my suction is 2"...pretty standard. I used a 2.5" nipple 12" long entering my pump. The 2-2.5 3-way Jandy valve can handle a 2" pipe inside the port or a 2.5" fitting outside the port. Pretty cool. My IntelliFlo primes in under 10 seconds every time from the first time I fired it up in mid-July to today. He claims this will allow the pump to run easier, quieter, and have longer life.

As to priming, to help answer GigaMike and Jason, the IntelliFlo is pretty intelligent about it (but you do PAY for that intelligence!): It has a whole menu dedicated to tuning one's priming procedure. The default is to turn on at 1800 rpm and attempt to prime for about 3 seconds. If sufficient flow is not achieved, it'll then ramp to max (3450 rpm) for the next 20 seconds. If sufficient flow is not achieved, it'll keep trying to prime at max speed for 11 minutes. At the end of that, it'll quit and produce an error. If at anytime during this priming procedure it detects insufficient flow, it can exit the program early and give an error. You can even program how sensitive it is to determining sufficient flow. The factory sets it at 1%...max sensitivity. After all that, it'll then resume its program. But, again, you do PAY a premium for this kind of flexibility.

So the bottom line is to provide good clean plumbing into the pump with minimal head loss, reasonable air tightness, and to understand if your pump has some intelligence when it comes to priming or if you can externally control your pump to help with priming if necessary. Perhaps you can program a 2-speed to run at high speed for 5 minutes (or whatever) when first turning on for the day and then it can drop to low-speed for the remainder of its cycle for the day.

Other tricks to dealing with priming can include a check valve placed inline to the pump such that when the pump shuts off, the valve closes and holds water in the pipe.