Can I effectively heat my pool using a saddle valve and flexible tubing?

[DaveC426913]

I have been planning a heat exchanger for my pool for quite some time. I'd like some reco's about pressures and pipe diameters.

See attached diagram.

The pool hose is 1 1/4" flexible PVC hose like this:
[URL]http://www.poolsupplies.com/images/products/tn_105550.jpg[/URL]
The pump is a standard Hayward 1/4 or 1/2 HP that generates somewhere around 20-40psi.

It seems to me (and the pool expert who gave me the idea) that I should be able to use one of these saddle valves:
[URL]http://img.diynetwork.com/DIY/2003/09/17/r107_1fb_lead.jpg[/URL]

and some flexible aquarium or other rubber tubing.

Some questions:

• Can I get a saddle valve for a 1 1/4" flexible PVC pipe?
• At 20-40 psi, will the saddle valve still be water-tight?
• What diameter tubing for the heat exchanger would be a good compromise between volume/throughput and surface area/heat exchange?
  1/4"? 3/8"? What's good?
• I'll need a pressure differential to get the water flowing through the exchanger. Where? (see 1 and 2 in diagram) I'm sure 1 will work. Will 2 work? I mean, I'm adding water back into the input. Does that compromise total throughput?
• Do I have to worry about whether the exchanger tubing will burst?

 

[Possibill]

I have been planning a heat exchanger for my pool for quite some time. I'd like some reco's about pressures and pipe diameters.

Dave,
to avoid the possibility of having a constantly plugged heat exchanger line when using any size pipe less than 1" in diameter, I would do the take off after the filter, not before it as your diagram shows. Also, feeding back into the suction side of your system would not only lower your exchange efficiency, it would short circuit your pool circulation somewhat and could cause even more significant problems.

If you're really intent on prolonging the life of your motor in this fashion, consider creating a venturi effect by crimping your post filter return line after your exchanger take-off and feeding your exchanger return back into your return line a foot or so after the crimp.

*]Can I get a saddle valve for a 1 1/4" flexible PVC pipe? certainly

[*]At 20-40 psi, will the saddle valve still be water-tight? that should not be a problem but you only have 20-40 psi on the pressure side of your filter - there should be a significant drop on the pool side

[*]What diameter tubing for the heat exchanger would be a good compromise between volume/throughput and surface area/heat exchange?
1/4"? 3/8"? What's good? use the size that you can wrap the tightest to get good coverage of the motor housing or insulate the entire pump and tubing combo well

[*]I'll need a pressure differential to get the water flowing through the exchanger. Where? (see 1 and 2 in diagram) I'm sure 1 will work. Will 2 work? I mean, I'm adding water back into the input. Does that compromise total throughput? yes (see comments above)

[*]Do I have to worry about whether the exchanger tubing will burst? yes, especially if you install the feed line on the pressure side and especially especially if you put the return line on the pump's intake line

 

[DaveC426913]

Dave,
to avoid the possibility of having a constantly plugged heat exchanger line when using any size pipe less than 1" in diameter, I would do the take off after the filter, not before it as your diagram shows.

Hm. Hadn't thought of that.

But wait, if my draw is after the filter, where is my return? It's got to be somewhere of lower pressure.

Also, feeding back into the suction side of your system would not only lower your exchange efficiency, it would short circuit your pool circulation somewhat and could cause even more significant problems.

Good points on both. I was thinking that 5 or 10% might not be significant.

If you're really intent on prolonging the life of your motor in this fashion,

Prolonging my motor is ancillary. I'm doing this to warm my pool by a critical fraction of a degree.

consider creating a venturi effect by crimping your post filter return line after your exchanger take-off and feeding your exchanger return back into your return line a foot or so after the crimp.

Oh that's how I get a pressure diff...

But I'm loathe to make any changes whose purpose is to lower the total throughput. You can never have too much throuput, but it's pretty easy to have too little.