Replacing a motor on a pump, and getting the correct size for your pool?

[mitchryan912]

While we're at it, my pump runs 24/7. Does that change the calculation for how many gallons need to be filtered per 8 hours? We don't really use it that often to need it to be cleaned 3x per day... or does that mean we probably ought to consider putting in a timer to limit how much it runs?

[mitchryan912]

A 1HP IG pump should be fine, but not a 1HP AG pump.

Are they constructed differently for each type of pool? I guess I'm potentially not following what you mean by this statement.

[CarlD]

Smoking motor is not good.
AG pumps are designed to run with the pool water higher up so there is gravity pressure. An IG pump is able to pump from the surface and pump the water up.

Further, most AG pumps are "up-rated" while IG pumps tend to be "full-rated". To super-simplify, it means that an AG pump rated at 1.5HP may have the same flow rate as a 3/4HP IP pump.

Re-read mas985's post above.

[mitchryan912]

OK, re-reading mas985's post. I think I understand it a bit more now that I did before... and now I think I might just benefit from going to a SMALLER motor and impeller after looking at the spec sheet for my pump. To answer his original question though, I thought I might need a bigger motor because I was seeing debris just float by my skimmer, so I thought maybe there wasn't enough suction to properly skim the pool?

To the specs: http://www.waterwayplastics.com/prod...d-pumps/smf-2/

According to their flow rate chart, the 1 HP motor I've had might just be too big. 40 ft of head for the skimmer line = 75 gpm flow rate, and that's higher than the rating on my filter. FWIW, I've got 25 feet of head to the other suction line.

I guess I'd be looking more at the 3/4 HP pump now, based on the flow rate chart. This is all assuming that I'm calculation my GPM's correctly (54 gpm to turn over the pool in 8 hours, 60 gpm flow rate of the filter, 44 gpm per suction line x2) Based on all of that, would I be correct in choosing a 3/4 HP pump instead? If I were to get a replacement 3/4 HP motor, would I also need to get a different impeller as well?

Thanks for all the help on this, BTW. Last year I got a crash course on chemicals, and now I'm getting a crash course on the mechanical aspects of pool ownership!

[CarlD]

mas985 is far better at figuring the mathematics of head to gpm to filter rate than I am.

[mitchryan912]

Hopefully mas985 reads this and can give some suggestions. I'm not sure how long I can let the pool go without circulation, as it's been since late Friday night that it died. I'm keeping the chlorine high to make sure stagnant water doesn't help lead to any funkiness going on in the water. Obviously manually skimming much more often than I usually do as well.

Here's some info on my filter. The pressure gauge on it seems to be broken, as there's no pressure currently, and it's reading 30 psi. When the pump is running, it typically reads 55-60 psi, so I'm assuming it's actually about 25 psi most of the time. I'm not sure if that pressure reading matters, but I'd seen some sites that used that to calculate the head (I don't have a way to check the suction pressure before the pump, at least not yet...)

[mitchryan912]

I'm leaning towards buying this replacement motor, an AO Smith USQ1102: http://www.amazon.com/Smith-USQ1102-.../dp/B007ATO2SK

It seems like it's direct replacement for the US Motors 1081 that was part of the Waterway pump we have.

[mitchryan912]

Thanks for the help! I ordered up the SQS1072R pump and the T10604 yesterday, and they should arrive tomorrow evening. Since everything was down, I went ahead and replaced the faulty pressure gauge on the filter too.

I just hope I can piece everything back together with the motor when it arrives. Any videos/tips on putting a motor back together? Anything that I need to be aware of?