Fafco panel leak - before I get on the roof

[1poolman1]

Thanks Dirk! I appreciate the step wise instructions - some is review.
I've worked a lot repairing 3/4 inch irrigation PVC and have screwed up many repairs while in a dirt hole with not enough wiggle room to move pipes to join the materials (while I have the glue on the pipes waiting to join).
I think the spray painted pipe has enough play. BTW -- Other than appearance, does spraying the PVC really protect the material? Maybe it keeps the pipe hotter don't know.

Look at enough PVC that is in the Sun and not painted and you will see that the area with the most exposure is brown. That is burn from the constant UV exposure, and not just on a roof.
I have found that using the least expensive, flat, black, Home Depot paint lasts as long or longer than any of the others. Used to be $.97, now $2.48 called HDX. Unless there is grease on the pipe, it will stick to most everything, never had to sand or clean other than dust (usually not even then). Will last several years.
Needs to be the flat, not gloss. Gloss will require cleaning, sanding, etc. but won't last any longer and doesn't look as good as flat. Flat hides a lot of imperfections in the plumbing, like glue drips, etc.

 

[Dirk]

Look at enough PVC that is in the Sun and not painted and you will see that the area with the most exposure is brown

The PDF I linked addresses that, and agrees. But also claims that that burn is only "skin deep" and won't affect pressure capacity, only impact resistance. I can't vouch for the author, I just grabbed it off the 'net.

I recall a member having to replace a length of PVC that just shattered. It was the only pipe laying on his concrete pad. My theory was that the pad contact increased the heat on the pipe. I think I recall it was part of his sand filter waste piping, which I suppose would mean it was empty most of the time, and so maybe didn't benefit from being "water cooled" like his other plumbing. All just anecdotal speculation.

But for me, because solar plumbing is in the worst location possible (in terms of UV), and is often empty, or filled with non-flowing water just heating up on the roof, and is an integral part of the plumbing under pressure, arguably the most pressure in the system (because when the solar is active the RPMs are high), it's just not worth gambling. Depending on how your pool was plumbed, a roof top pipe failure could empty your pool, sending all that water all over your roof and yard, and/or drain just enough of the pool to burn up your pump (I'm a worst-case scenario kind'a guy). So it stands to reason to apply what reasonable precautions one can to avoid that failure.

1poolman1 suggests a simple solution. A PVC manufacturer's website suggested just a coat of latex UV house paint works well, too. It's cheap insurance.

 

[1poolman1]

The PDF I linked addresses that, and agrees. But also claims that that burn is only "skin deep" and won't affect pressure capacity, only impact resistance. I can't vouch for the author, I just grabbed it off the 'net.

I recall a member having to replace a length of PVC that just shattered. It was the only pipe laying on his concrete pad. My theory was that the pad contact increased the heat on the pipe. I think I recall it was part of his sand filter waste piping, which I suppose would mean it was empty most of the time, and so maybe didn't benefit from being "water cooled" like his other plumbing. All just anecdotal speculation.

But for me, because solar plumbing is in the worst location possible (in terms of UV), and is often empty, or filled with non-flowing water just heating up on the roof, and is an integral part of the plumbing under pressure, arguably the most pressure in the system (because when the solar is active the RPMs are high), it's just not worth gambling. Depending on how your pool was plumbed, a roof top pipe failure could empty your pool, sending all that water all over your roof and yard, and/or drain just enough of the pool to burn up your pump (I'm a worst-case scenario kind'a guy). So it stands to reason to apply what reasonable precautions one can to avoid that failure.

1poolman1 suggests a simple solution. A PVC manufacturer's website suggested just a coat of latex UV house paint works well, too. It's cheap insurance.

I've seen those burned areas of a PVC pipe actually bulged from the pressure. Usually on the pipe between a piece of equipment, especially between pump and filter. It also just looks better on a roof to have the pipes painted.

 

[aquaman]

So a little question has big answers!
Black PVC pipe - which is still Schedule 40, which is NOT ABS -- correct and correct?
CA code! duly noted.
Repainting is a bear... underside is problematic. Brush and not spray? As paint fades I can tell installers sprayed it - don't remember if that was done before installation. Would imagine so, kind of dicey with wind and overspray.

 

[Dirk]

Black PVC pipe - which is still Schedule 40, which is NOT ABS -- correct and correct?

Yes and yes. Special order stuff. Got it from a local solar installer.

Repainting is a bear... underside is problematic. Brush and not spray?

Don't worry about what you can't get at, it's probably shaded from the UV anyway. Slip a tarp or piece of cardboard between pipe and roof and brush or spray. You might miss as little as 1/2" on the bottom that way. As you say, spraying up on the roof might be a challenge, brushing is easier to control. Slide the cardboard along as you go. Nobody's going to see any brush marks!