Collapsed piping on roof!

[YonnyPiscinas]

A month ago I returned from vacation to find 2 collapsed pipes on the pergola where the solar collectors are situated. Only on the outlet side.

I had left the solar collector valve a little open just to have a small amount of flow through them.
After entering the house and checking the pool I noticed water had been dripping down from the pergola (where the coupling came a little lose). Went up to investigate and to my surprise, I found these 2 collapsed pipes!!

I have communicated with the solar collector's supplier and the pipe manufacturer. They still insist a vacuum release valve was not necessary.
They had never seen this happen before. Pipes are the correct spec for pool piping.

I am logically thinking that a large vacuum and excessive heat had caused this.
Maybe my fault for leaving the valve just slightly open , the bypass causing a negative pressure effect on the outlet of the collectors possibly?

The piping is good to 60c and the panels 90c+.

A very rare occurrence.
I leave the valves fully open or fully closed now. Still pending to install a VRV for now. 65USD here is not cheap.


Fixed the piping section last night at least to regain the full flow.

Thanks

 

[needsajet]

Sorry to hear of your troubles.

The VRV is necessary for when the system shuts down and drains. If enough water was always flowing through it, the VRV would not be needed, but then you would be losing more heat from your pool at night. When pool temperature is reached and the system shuts down, there is vacuum (negative) pressure and a lot of heat on the pipes when the sun is still out.

 

[YonnyPiscinas]

As a precaution, I've had it running all the time while hot. Set up with a switch and temp probe now.
but yes this is also an issue as the pool has been getting too hot.

With the VRV I'll be able to shut them down during the day without the risk of overheating and collapsing again with the negative pressure.

It's appalling that a dedicated company supplying solar panels for central hot water and pools did not recommend installing this valve.
They are still surprised this occurred.

One other interesting observation. At night time when the temp drops, I can feel cool water from convection currents coming out of the jets (pump off).
I assume this is from the cold panels full of water at night time.
When I emptied them manually the other day to fix the piping there were no cold convection currents coming out of the jets.

 

[needsajet]

Another good reason for the VRV! Let us know how it all works out when completed.