black pipe heater - running the pump question

[donintn]

I am pretty sure I know the answer to this, but I am just double checking. I made a black pipe solar heater - I have approximately 700 feet of 3/4" black pipe on my roof and am using a separate 1/2 hp motor to pump the water. Seems to be working well. My question; after researching it, I am pretty sure I am just supposed to run the pump all day but I just can't quite wrap my mind around that.
Running constantly, the water ends up feeling pretty cool on my hand. I have the pump on a timer and I have been setting the timer so it runs for about 2 hours then stops for an hour. Of course this way when it starts back up the water is extremely hot on my hand until fresh pool water makes it through the pipe.
I should be running the pump all day though instead of stopping it shouldn't I ? I did not do the math but I have seen many a post talking about it and it is supposedly better, but from a physical point, it just seems better stopping it and feeling that hot water.

Guess I just need to be told I am doing it wrong.
Thanks for any info.

Our days are great now but we are still getting down in the 40's at night so even with the solar cover on, ithe water is still too cold to jump in and my granddaughter is like a mermaid and can not wait to get in.

 

[jblizzle]

Welcome to TFP!!!

Yes you should run the pump continuously when there is sun on the solar heater. The heating is actually most efficient when there is only a few degrees of temperature rise.

Ideally one would have a solar controller that would only turn the solar on when heat was available. For example, today it is cloudy, so mine may not turn on. If it did, I would actually be cooling the pool.

Of course realize that solar heating is all about square footage of exposure. you currently have a little over 40 sqft of exposure (not sure how big your pool is). I have 500 sqft of solar panels. So, you need to have realistic expectations of how much heat your solar will add.