I need a pump/motor reccomendation for water solar, 2 1/2 story

[Chuckiechan]

My son is getting solar water installed and we've decided to install the new motor & pump ourselves.

The solar company said a 1 1/2 hp would work to push the solar properly.

The one we will be replacing is a Century with a label "Total HP = 1.24. The specification plate says HP 3/4. I don't understand that.

Also, he has a booster pump for his pool sweep (pressure type). Is that likely to interfere with anything?

I'm inclined to go with a 2HP pump and motor, or a 1 1/2 pump and motor, preferably Pentair or Hayward. Is there any benefit to having the motor oversize by 1/2 HP?

I could use some suggestions for a good budget unit. He doesn't have water features to speak of.

Lastly.....

Should we decide to look at two speed again, do they have a sensor to switch to high speed when the solar calls for water and more power is needed? Or is it more complicated than that?

 

[mas985]

Why are you replacing the pump? A 3/4 HP should be big enough for solar. My 1/2 HP pump was big enough to run solar on a two story roof.

Should we decide to look at two speed again, do they have a sensor to switch to high speed when the solar calls for water and more power is needed? Or is it more complicated than that?

Some solar controllers will do this, you just have to check the feature set.

 

[Chuckiechan]

The solar installation company said it would not do the job, so we have to go with that.

 

[mas985]

How high is the installation?

What is your current pump model?

Solar companies always oversize the pump because it is no skin off their nose. They don't pay the electricity bills but you do. That new pump will cost almost twice as much to run and in CA, that's not cheap.

Also, how much is he charging for the new pump? Have you looked into a VS pump?

 

[borjis]

I can vouch for this. You don't need a bigger pump.

I had that happen too, pool co inspector during home purchase said the existing 3/4 hp (1.25 sf) motor was inadequate for the solar operation (single story)
and I almost went and bought a whole new motor til I posted on this forum and thanks to Mark's advice, I didn't need to buy one.

The solar worked great all last summer once I fixed the 1 leaking panel. They were Solar Industries panels.

Like Mark said it's no skin off their nose. It wouldn't void any warranty, so stick with that one you already have.

If they persist just tell them you have a friend that works in Hydraulics and he said it's fine.

 

[Chuckiechan]

The current pump plate is attached.

I did the calculations .75 HP x 1.65 Service Factor = 1.24 Total HP

I'll run it by him and see where we are.

EDIT, it seems that motor should be able to pump 60 feet, or close to it.

 

[mas985]

EDIT, it seems that motor should be able to pump 60 feet, or close to it.

If the height of the panels is about 1/2 the head loss of the pump at 40 GPM, you are good to go. Even at little more than 1/2 will probably work ok.

 

[Chuckiechan]

He told the solar company to install it As Is, and if there is insufficient pressure, we'll replace the existing pump & motor.

Thanks for your help and for saving him a butt load of money!

 

[Chuckiechan]

For a follow up...

The original pump works fine, has good pressure. The gauge on the sand filter is at 20 lbs with the solar on. (I'm not sure how clean it is).

All is well.

Thanks for saving us a ton of money.

 

[mas985]

 

[borjis]

Right on.

When I engaged my solar, it would always go up 5 psi above the usual.