Solar panel plumbing mystery

Wondering if anyone could give me advice on a problem I have run into in connecting some new solar panels into an existing set of solar panels I now have connected to my pool?

My problem is at the t shaped junction point between the
1 1/2" pvc pipes which return heated water to my pool after it has run through the two separate sets of panels. I installed a flow control valve on each of the pipes leading from the panels to the T junction. I also installed a flow meter on each pipe so I could see how much water was flowing through each panel and equalize the flow rates (or get higher flow from whichever bank of panels is better oriented toward the sun at a given hour of the day). Unfortunately, no matter how I set the flow control valves on each pipe, 100% of the flow goes through one pipe and none through the other. In other words, no matter how slowly I open one valve and close the other, instead of the flow from one set of solar panels slowly increasing and the other decreasing until the desired balance is reached, the flow remains 100% from the A set of panels and 0% from the B set until a certain point is reached, then it switches instantaneously to 0% from A and 100% from B, with no setting where there is flow through each set simultaneously.

The only thing I can figure out is that the flow from set A into the T junction completely blocks the flow from set B until the flow balance between A and B reaches a certain point, then the blockage reverses. This seems completely counter intuitive to me and I am looking for advice as to how to rectify the situation.

Does anyone know whether installing a flow direction check valve on each of the 1 1/2" pipes returning water from each set of panels would solve the problem of one flow apparently blocking the other?

You should probably also know the following: 1)Water flowing from the pool pump to each set of panels goes through a 1 1/2" pipe which is separated into two 1 1/2" pipes at a T junction identical to the one that rejoins the two flows after they go through each set of solar panels: 2) There is a bypass Jandy valve located on 2" pipe running between the pool pump and the 2" pool return pipe. This allows regulation of the total flow of water into the 1 1/2" pipe leading to the two solar panels so that flow to the panels can be entirely shut down: 3)There is almost zero room in a confined space in which the pool pump, filter, and plumbing are located so that replacing the 1 1/2" pipe currently leading to and from there to the solar panels with 2" pipe would be almost impossible. It did occur to me that the 1 1/2" return pipe leading from the T joint back toward the pool might be too small to handle the water from the two 1 1/2" pipes flowing into it. However, since those two pipes are fed by a single 1 1/2" pipe from the pump, why wouldn't a single 1 1/2" pipe also be adequate to handle their return flow?

It's all a mystery to me. Can you help?

Thanks for any help you can offer.

Welcome to the forum! Unfortunately, forum traffic is very, very slow this time of year since most folks have closed their pools for the winter. You may still get some responses but may have to be patient and keep checking back. In the meantime though, you can LOG OUT and go to the main forum screen, then look for any post by me, Watermom, or Pooldoc and follow the google search link in our sigs to search the forum for other posts that may be similar or helpful. Sorry I can't answer your question, but maybe that will help :)

Hi!
I'm having trouble picturing how your panels are connected. Can you make a diagram or post a pic(s) to help visualizing it?
One thing I do differently from you is my panels, once split, stay split and each has its own return to the pool.
I do know that sometimes the built in valve on the roll-able panels can be confusing and you may need to re-plumb the panels so the entrance is at one corner and the exit at the other, with a new valve at the input and leave the built in valve open.

Carl

You'll need to post photos of your set up -- use Flickr, Picasa, Webshots, etc.