Question on PB's pump sizing

[txborn]

Got a quote for an IG pool. Due to easement restrictions, it is a small pool/spa - about 9,000 gallons. Here are the specifics:

Hayward 60 sq. ft. DE filter
2 Pentair surface skimmers - separate pluming and valves
Polaris 280 with booster pump
Waterfall with 19 foot weeping wall
6 foot diameter raised spa
2 1/2" skimmer and main drain lines
6 adjustable water return inlet fittings - 1 1/2"
2 HP Hayward Northstar pump single speed

After reading many threads and doing research it seems that a 2HP pump is a bit overkill. PB said the spa needs that size (6 jets) and using that pump for filtration/circulation will allow a minimum pump run time for pool turnover. Also said I can't run waterfall/weeping wall at the same time as the spa. He said he will put any size pump I want but is sticking with the 2HP 'cause of the spa.

Could I get a 3/4 HP pump for the pool filtration in addition to the 2 HP for water effects/spa? Or any other advice?

Thanks

[mas985]

You have identified all of the options that I would have suggested.

1) Keep the pump the way it is which I don't recommend.
2) Go with a 2 speed 2 HP pump. PB is probably correct in that you need a 2 HP pump for 6 jets running through the filter.
3) Go with separate pumps. This allows you to customize for the application but will cost you a bit more.

Option 2 will probably save you the most money in both hardware costs and on going electrical usage. The low speed of a 2 HP 2 speed pump is about the same power as a 1/4 HP pump so your electrical usage will be fairly low. With only 9000 gallons, you don't need much HP for circulation. 3/4 HP is probably overkill as well.

In either case, you may want the flexibility of having a separate pump for the waterfall so you can run it at the same time as the low speed circulation or while running the spa. It really depends on how you plan on using it and how much money you want to spend.

[txborn]

Thanks for the reply Mark. I discussed a 2 speed pump but he said it's difficult to get a control system that you can switch speeds back and forth. This being my first pool I am still in the learning stage about this. Guess he means that I would have to manually switch from low to high speed? Read the Hayward manual but didn't mention 2 speed pump operation and control specifics.

Still open to an additional pump with the 2 HP to power spa and water features, maybe go down to 1/2 HP for filtration.

I noticed you have the Hayward 400,000 BTU heater. That's the one he recommended for me as well; said even though it's a small pool and spa, said it would heat faster and more effeciently than the 250,000 BTU model. This is new home construction so I can install any size gas line easily at this point.

[CarlD]

If you have easy access to the pump then a manual hi-lo speed switch is all you need. Even if you don't it's just not that complicated a wiring job for a competent electrician. PBs like that stuff simple.

[txborn]

Carl, I will have easy access to the pump. If I stay with one pump, if I want to turn on the spa or water features (pump on high) will I still be using the SWG and filtering the water at the same time? Is it just a matter of how the valves are configured/plumbed?

Hope that wasn't a dumb question but still a little ignorant how that all comes together

[msm859]

I do not profess to be an expert however, from what I have researched 2 hp pump is too big for your spa. only so much gpm can go through your pipes. what size is the plumbing to the spa? how long is the run, how many 90's? etc. I might look into the Pentair Intelliflo -- which is a variable speed pump. my guess w/ a 2 hp pump you will be throttling way back which is just wasting energy making your pump work harder.

[mas985]

txborn,

Are you planning for an automated control system? If not, it is one more thing to consider although somewhat costly. It sounds as though you are going with a SWG but a full controller is only a bit more.

I have the Goldline (now Hayward) Aqualogic unit which controls all of the valves, solar, pumps (including 2 speed), lighting, SWG, pool cleaner, plus anything else you can think of. It is around $1000 last time I checked but I liked the timer and remote feature plus it was only an additional $400 for the SWG. So it might not be much more than you are paying for the SWG.

Given you have a water feature, a full controller would allow you to turn on and off that as well. Plus it gives you the option to put the features on timer. It is nice for the spa since my kids tend to leave the jets and heat on ($$) and I have it on a timer so it automatically shuts off after 1 hour of use. If they are still in it, they can turn it back on with the water proof spa remote. The unit has wireless remotes you can get for the house and spa which are nice.

As for the heater, the larger the better for time to temp so you don't have to wait long.

[mas985]

I do not profess to be an expert however, from what I have researched 2 hp pump is too big for your spa. only so much gpm can go through your pipes. what size is the plumbing to the spa? how long is the run, how many 90's? etc. I might look into the Pentair Intelliflo -- which is a variable speed pump. my guess w/ a 2 hp pump you will be throttling way back which is just wasting energy making your pump work harder.

Spa jets generally require 15 GPM per jet for adequate action. With 6 jets that is 90 GPM. A spa shared with a filter and heater even with 2 1/2" pipes is likely to be above 65 feet of head loss so a Hayward Northstar full rated 2 HP would yield about 110 GPM or 18 GPM per jet. However, 2 HP max rated would yield about 90 GPM so it really depends on the pump rating as well as what the user likes, strong or weak jets.

However, a dedicated jet pump without filter and heater head loss would not need to be as large.

[txborn]

Here is some more detail.

Equipment is less than 25 feet from pool. Aqua Rite SWG. Option for Goldline Aqua Logic automation AQL-PS-4, add $2,400 Think I will buy the sub panel and do that myself. Spa has 6 - 1 1/2" Theraputic Hydrobody jets plus a 1 1/2" center fountain. They heat form PVC so as not to have too many 90's. Each jet outlet is homerun. Doing the calcs, I came up with 25 gpm for a 6 hour turnover based on size. For filtration only, a 2 HP is, IMO, way overkill. It would turn over in less than 2 hours and I don't think that's enough time per day to have a pump run. PB doesn't think it's an issue.

I considered a Pentair Intelliflo but can't find a lot of feedback on it. For that kind of money I would be more comfortable if I had more info.

This company has a great track record and the owner personally visits each jobsite and has been great in answering my questions and concerns. He will do anything I want to do; I just need to get a game plan.

[msm859]

remember though there is no risk for the builder to give you a pump too big. he can adjust the spa nozels down. you though end up paying for the wasted energy if it is too big. if it is too small you will of course complain to him. what you really need to know is what the pressure is on the system "feet of head" to determine hp need.