Question on PB's pump sizing

[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.