Why am I supposed to wait 15 minutes after backwash to turn on solar heater?

[TreeFiter]

I have a customer that just had solar panels installed for their pool. I was told, and there are warning labels on the system, that I must wait 15 minutes after backwashing to turn on the solar system again. Does anyone know why this is necessary, or what the reasoning is behind it?

Thanks

 

[Charlie_R]

I would suspect that it is to ensure no leftover debris in the system has a chance to find it's way into the panels.

 

[Bama Rambler]

Some filters don't have a rinse function on the backwash valve and like Charlie R, I suspect it's to allow time for the filter media to be rinsed so as not to introduce debris into the solar panels that could cause a blockage or wear in the system.

 

[Isaac-1]

I agree with the others, and wanted to note that some styles of solar panels have smaller openings on the headers going into the panel tubes than others.

Ike