Experts, I Need Help w/ First Pool Purchase

[mas985]

Moderators and experts- what do you think about the info on the page below?
http://www.poolplaza.com/two-speed-pumps.shtml

I tried to fix the link. If it still doesn't work, just go the home page (www.poolplaza.com) and you can choose the link directly below where it states Pumps-One Speed or Two Speed, What's the difference?

Is it correct? I also found the 2 speed super pump at this same site. Thanks, Webfeet

The poolplaza site is a good place to learn about pumps and hydraulics. From the diagram they have on that page you will notice that on low speed, The head is 1/4 and the GPM is about 1/2 of that on high speed (GPM is proportional to RPM) so your turnover is twice as long. Although it is true that the energy draw is about 1/3 of high speed, since you have to run it twice as long, the cost savings is really only about 33% (2/3). However, over the life of the pump, this is quite significant.

Since your pool has not been built yet, a head calc is somewhat difficult. You will need a detailed plumbing diagram with all of the bends. However, given that most pools are between 45-65 feet of head, this swag should get you close enough when determining turnover.

If you decide to go with 1 1/2" pipes, then make sure they run lines from each return, skimmer and main drain all the way to the pad. This will minimize the head loss and reduce the time for a turnover. In terms of head loss, here are a few rules of thumb:

2 - 1 1/2" pipes is about the same head loss as 1 - 2" pipe.
3 - 1 1/2" pipes is a little more head loss than 1 - 2 1/2 " pipe

An alternative but less attractive plumbing option is to go with a single 2" line for the returns and a single 2 1/2" line for the skimmers and main drain (split at the pool). Even better yet is to use 2" lines from each return, skimmer and drain back to the pad.

The plumbing design of a swimming pool has one the largest impacts on the life cost of the pool so it is very important to get it right.

[EDIT]

One more thing:

Although I am sure the Superpump is a great pump, I would encourage you to compare pump head curves between the pumps. For example, the 1 HP uprated Superpump has a 50 GPM at 50 feet of head while a 1 HP uprated Northstar has 70 GPM at the same head. This is an increase of 40% which means 40% less run time and 40% energy savings on top of that from the 2 speed, assuming the same current draw. Also, the Super II is not far behind the Northstar at 67 GPM for 50 feet of head. The Superpump is a medium head pump while the Northstar and Super II are high head pumps which is more appropriate for your pool.

[webfeet]

Thanks Carl and Mark and everyone else. I am leaning toward a 2 sp 1 1/2 hp- will make all the comparsions recommended by you guys. I want the 2" pipe, but the builder wants a minimum of $2000.00 to go from 1 1/2" to the 2" ( this does not include the upgraded pump and filter: $600-$700 more). The charge for the pipe seems way to high. Are 2" pipe and fittings that much more expensive? My pool will be a grecian style (8 sides) 40'6" x 20'6". I will have 2 skimmers, 2 returns and a cozy cover semicircle spa (built into the wall, but still uses the pool water). The spa has 6 jets.
One other thing, 2 returns do not seem like enough? Are they? Thanks Web

[Poconos]

The only question I can answer is the price of the pipe.....WOW. $2K? I'm guessing as I don't keep those detailed records but maybe $3 more per 10' going from 1.5 to 2" pipe? Yes, 2" PVC is a little more expensive then 1.5 but just a little unless you're going copper. There is a bigger percentage difference when you talk ball valves. Just go to a Home Depot and check the plumbing aisle.
Al

[mas985]

$2k is way too much. After checking HD, go over the prices with the builder and see if there is not some mistake.

Also, you say you are leaning toward a 1 1/2 HP pump. Is that an uprated or full rated pump?

I guess I missed the spa before but a 1 1/2 HP uprated pump may not be enough for the spa if you are using a single pump or are you going with a separate pump? Each jet should have about 15 GPM to provide enough action. That is 90 GPM and if you figure on 60 feet of head for the spa, a 1 1/2 HP full rated Super II pump would only provided 12 GPM at best. Modest jet action. Hopefully, the builder will be using at least 2" piping for the spa.

So if you are going with a single pump, a 2 HP full rated 2 speed may be a better option but you should go with at least 2" plumbing. Otherwise a two pump solution may be better so you can get a low HP for the pool (3/4 HP) and a higher HP for the spa jets.