spa plumbing and pump size for solar addition

[Nova13]

I have a Vita spa with a Super flo pump

I was thinking that I'll just use the pump that's pictured for the jets when using the spa.

I need to add a pump to filter the water and pump it up to a story roof with several fafco panels.

two questions what size pump do I need?

where do I T into the plumbing in that pic?

tks

 

[mas985]

Almost any size IG pump is big enough for a two story lift. I am currently using a 1/2 HP Northstar wet end for a two story lift and it primes fine. If you are interested in using an AG pump, they are cheaper, then the choices are somewhat limited but you just need to check the head curve of the pump and anything over 40 GPM @ 50' of head (double the lift height) should give you plenty of margin. But from your post it wasn't clear if it is one or two story roof. One story will give you more AG options.

 

[Nova13]

Oh the lower roof edge is 10' above ground, and the solar panels are 12' long, so it's about 23-25 foot total height.

Any opinion where to cut into the system for the run to pump and roof return

 

[mas985]

Is there a reason you don't want to use your existing pump for solar too. It will reduce the flow to the jets some but you may not need much flow for the panels. Is it just a single 2x12' panel? If so the existing pump may be able to handle it.

 

[Nova13]

I have 3 panels 4x12 I can use for the spa, so rather than supplement with electric I just want to set the system to about 100 or so

 

[mas985]

That is a lot of surface area for the the spa. It will heat pretty quickly so it won't need to be on for very long. Are you planning to have a solar valve or just use the second pump to turn solar on and off?

 

[Nova13]

I was think a second pump, like maybe a 1/2 or 3/4 but not sure which one initial cost an the operating cost.

The second pump would also go thru a filter and perhaps UV also.

 

[mas985]

Looking at your existing plumbing again, the pipe size looks to be 1 1/2"? That is a little small to be running two pumps on although the runs are very short. Do you have any more pictures for the plumbing a little to the left?

It is going to be a very tight squeeze to plumb a second pump. It might be easier to just use your existing pump with a solar valve. I don't think I ever got answer as to why you don't want to use the existing pump for solar too.

 

[Nova13]

Well I thought I would only use existing pump when using the spa and the second to recirec thru the solar and filters.

I can get more room to either side because I'm not using the wooden shell, it will be put into the ground about 18"

 

[Nova13]

You started me looking for more room, I opened up the wood cab to the right there's another motor, a 3 hp Manetec, wow had no idea now I really don't need another pump.

Not sure why there's two need read the manual a bit.

Here's a pic of that

 

[mas985]

If you try to use any part of the existing plumbing, it is going to be very complicated and messy. Probably the only way to do this is to add separate suction and return ports with an additional pump so everything is isolated. But it probably means cutting into the shell.

I would really rethink what you are trying to do. Solar is not a great solution for a spa. There are only going a handful of days when you can actually heat the spa up to 100F. The panels have to be much higher temp to get to 100F.

 

[Nova13]

Been thinking about this, maybe I can branch off the 3hp return to the solar panels by placing a flow meter inline I can supply the 4gpm per panel.

returning from the panels just cut in a bulkhead fitting to return the water

 

[Nova13]

Found this info online not sure how accurate.

It is worth defining and
..distinguishing the difference between glazed and unglazed panels.

..Unglazed panels, the standard for most pool owners who merely want to extend the pool season from
..spring through fall, are large, bare heat exchangers through which pool water is circulated and heated.
..They can be made of metal, plastic, or rubber, and pretty much perform with equal efficiency.
Glazed panels have the same "guts" as copper unglazed panels, but the absorber is placed in a metal box enclosed in glass and insulation to provide a greenhouse effect. This gives the glazed panel an efficiency advantage over the unglazed type when you are trying to achieve heating in a cooler and windier micro-climate, or to temperatures over
90 degrees.

Enough glazed panels can provide year around performance for spa heating, while unglazed panels can normally heat the spa to the 95
.100 degree range for six months with preheat capabilities in the colder months. The unglazed panels
..can work well on a spa, despite their decreased efficiency at the higher temperatures, because they are
..servicing a much smaller body of water than that of a pool.