What if I can't make my system drain completely?

[pooldork]

I got a hold of some solar panels at a good price and want to put them on my roof for the pool. The problem is there's no easy way to run the water from the pump up there. Pool is on the north side of the house, so the most direct route to run the pipes would be up the side of the house, over the ridge and then to the bottom of the panel. The obvious problem with this is that the high point on the return would be above the panels and thus, water wouldn't drain out of the panels when the pump stops running.

I would put in drain valves at the bottom of the panels so that I could drain everything at the end of the swim season, but is there a drawback/danger in basically having standing water in the panels like this?

Doing it the "right" way would involve a huge amount of trenching and breaking concrete. Probably leaning toward doing this anyway (much to my wife's chagrin) unless someone can convince me it's not that big a deal to go over the ridge and back again.

Thanks.

[Naptown]

can you run the pipes along the side wall and the up maintaining a grade back to the pump?
You cannot leave water in the collectors over the winter. If you have no other choice then when shutting the pool down disconnect the pipe from the low end of the collectors (make sure you slope the collectors to a low point on the roof)
That will drain the collectors and the rest of the pipe to the pump if enough grade.

[pooldork]

can you run the pipes along the side wall and the up maintaining a grade back to the pump?
You cannot leave water in the collectors over the winter. If you have no other choice then when shutting the pool down disconnect the pipe from the low end of the collectors (make sure you slope the collectors to a low point on the roof)
That will drain the collectors and the rest of the pipe to the pump if enough grade.

Fortunately, I'm in Southern Cal, so I don't need to worry about freezing, but I would still drain them anyway just because I don't like the idea of them just sitting there full of water. Is there any danger in letting them sit full like this during the swim season? Will salt water sitting in there like that be problematic?

I'm still trying to figure out if there's some easy and not-so-obvious path I could route the pipes and maintain grade, but that's proving tricky if not impossible. I may just try it this way first before I embark on the digging (which would take huge amounts of time or money).

Thanks for the help!

[Naptown]

You would probably want to flush them every other day or so if the system is not active and coming on to heat just to keep the chlorine or salt levels up to prevent bacteria from growing.

[pooldork]

Sounds good. This has got me thinking--what do people do in scenarios where the panels are located downhill from the pool? I had a neighbor once with this set up and I can't imagine he went out there and drained them regularly--seems like a lot of water & chemicals to be losing. In my case, I can run a hose back to the pool and would do it that way, but like I said, it got me thinking.

[Naptown]

Where I am it freezes in the winter so all systems must be drained. In that case a drain valve at the collectors at the low point. Generally they come on enough that stagnation is not a big issue and at the end of the season pool levels are dropped anyway so the water in the collectors running out is no big deal. We sometimes use them for cooling the pool which further reduces the stagnation effect.

[inetdog]

Sounds good. This has got me thinking--what do people do in scenarios where the panels are located downhill from the pool? I had a neighbor once with this set up and I can't imagine he went out there and drained them regularly--seems like a lot of water & chemicals to be losing. In my case, I can run a hose back to the pool and would do it that way, but like I said, it got me thinking.

You do not need to drain them very often if you just pump some water through them regularly for a few minutes instead. Draining would happen once or twice a year when you decide to shut down the heating system. If you use the heating system year round and do not have to worry about freezing, you could just drain off a little water every not and then to remove sediment, etc.

The two main uses for a drainback system which lets the panels drain every day when you turn the pump off are:
1. Prevent loss of heat at night better than just closing a valve would do.
2. Accomodate using the panels during the day with sufficient solar heat even though the night-time (or even daytime!) air temperature is below freezing.

[Naptown]

2. Accomodate using the panels during the day with sufficient solar heat even though the night-time (or even daytime!) air temperature is below freezing.

that will not happen unless the object is to keep a pool from freezing during the winter which would be a tremendous waste of electricity. These collectors are unglazed black plastic. Once the pool temperature is 20^oF above the ambient temperature the BTU output drops to almost nothing.

[Beanyboy57]

I got a hold of some solar panels at a good price and want to put them on my roof for the pool. The problem is there's no easy way to run the water from the pump up there. Pool is on the north side of the house, so the most direct route to run the pipes would be up the side of the house, over the ridge and then to the bottom of the panel. The obvious problem with this is that the high point on the return would be above the panels and thus, water wouldn't drain out of the panels when the pump stops running.

I would put in drain valves at the bottom of the panels so that I could drain everything at the end of the swim season, but is there a drawback/danger in basically having standing water in the panels like this?

Doing it the "right" way would involve a huge amount of trenching and breaking concrete. Probably leaning toward doing this anyway (much to my wife's chagrin) unless someone can convince me it's not that big a deal to go over the ridge and back again.

Thanks.

Why can't the pipe run through the ceiling space? That way they could still connect at the lowest point of the panels and have sufficient grade to allow gravity to drain all of the water assuming that your roof is a gable or A frame type. We do this all the time in Australia when we connect our solar hot water systems. By the way, we have heat exchanger systems which are far more efficient than the old fashioned calorifiers that you guys seem to be talking about.

[Naptown]

Running pool water through the attic is an accident waiting to happen.