Tree roots block the return lines?

[Jwfi]

Hello, we have an in-ground pool and the pump does not prime when turned on and the cartridge filter pressure goes very high quickly. Both the pump and the cartridges are new. So the problem seems to be on the return line. There is a tree close to the pool equipment and pipes so we suspect the tree roots might block the return. We did the following experiments:

1. we took the filter lid off and took out the cartridges. Placed a drain king bladder at point A in Fig. 1. Turned on water hose to full. Saw water leaking back into the filter at point B, eventually filling the filter full. So we thought connector at point B is leaking.

2. We wanted to check if the rest of the return line had no problem, so we placed the drain king bladder into the pipe feeding into the return line switch. Turned the switch to Pool Return and turned on water hose to full. Could not feel any water movement at the return jets on the pool walls.

3. Then turned the switch to Water Feature and turned on water hose to full. Saw water first dripping down the column of sheer decent #1, then water started dripping down sheer decent #2. We stopped then.

For experiment 3, we are confused why the water is not coming out the sheer decent openings like it supposed to (as an arc of water, but instead dripping down the column indicating low water flow). But the city water pressure is 40-60 psi, higher than the 15psi out of the filter. So does this mean the pipes are blocked resulting in low water flow? But there are three separate pipes connecting from the switch to each of the sheer decent. How can three lines be blocked the same way by the roots?

For experiment 2, we also don’t know why we could not feel any water movement at the return jets. The water hose pressure should be >40psi, higher than the filter pressure.

Question: how can the tree roots block all 4 return lines (1 pool return and 3 water features) the same way, producing low water flow in all 4? If not, how to explain experiment 2 and 3? Thank you very much!

 

[JohnT]

Welcome to TFP!

The flow through a Drain King is much less than through an open hose. It’s just a trickle compared to what the pool plumbing can handle, and even the open hose is much less than what the pump puts through the pool plumbing. The pool pump moves somewhere around 10-12 times as much water as a hose can flow. Pressure only becomes an issue when water flow is restricted by things like the filter or pipe size. Volume of water is the key with pool plumbing.

I’m not sure how the pressure gauge reads high if the pump doesn’t prime. With no flow, there should be no pressure.

If tree roots have penetrated the return lines, you’d be leaking water like crazy.

What pump and filter do you have? Has this equipment worked properly for you before, or is anything new?

Can you run your filter with no filter element in the housing?

 

[Jwfi]

Thank you so much for the information! We think that explains the low water flow in our experiments 2 and 3. We will try to do our experiments 1,2,3 without the drain king to see what happens.

We read on the web that filter pressure is high when the pump does not prime only happens when the return line is blocked. The cartridges are new. So we didn't run the pump with no cartridges in the filter. We have Hayward 425 Swim Clear Cartridge filer and Hayward 1hp Tristar pump. The system was fine before but the problem happened (pump does not prime when filter pressure is high) so we changed both the pump and the cartridges and the problem is still there.

Question: can the tree roots squeeze the pool return line but not penetrate it and as a result block the return? Thank you very much!

 

[ajw22]

Is your underground pipe solid schedule 40 PVC or some type of flex hose?

It is doubtful tree roots can squeeze or break schedule 40 PVC.

Water pressure is inversely proportional to pipe size. You can get high water pressure from a small house water pipe or garden hose. When that same flow is put into a 1.5” PVC pipe the pressure will drop.

 

[Newdude]

I'd try to prime through the waterfalls. If they worked, you'd prove it to the return line or the valve. They are likely dripping because it has openings way bigger than the garden hose. Then i'd open up the valve and Drain King the return line if nothing was obviously wrong inside.