Solar Panels intallation and plumbing

[el_steak]

I bought 4 solar panels last fall to heat up my pool. It's now spring and I'm ready to proceed with the installation. I've read a lot of info from many sources and came up with the following schema for the installation. Can the solar panel experts take a look at it tell me if anything is wrong. Thx.

 

[JohnT]

I don't like the valves you show, particularly the one before the three-way and the one between the two check-valves. I think your three-way will do everything you need. The bypass valve might help you get flow right. My concern is that the valves might make it easy to accidentally shut off the flow completely, which could result in high pressure in the panels if the left-most valve and the bypass valve were both closed.

Often, valves are installed on solar in areas where pools are not winterized so if a freeze occurs the pump can be run without any risk of water entering the solar. If your three way is set to bypass the solar, it and your check valve keep water out of the panels, and you are too far north to have anything in operation when freezing weather hits.

Often, you put a check valve in the spot you asked about to keep the water in the panel from lifting the skimmer basket and flushing the crud back into the pool.

That's the normal spot for the vacuum breaker.

 

[JasonLion]

You need a check valve after the filter. Without it the pump and filter will drain, which you don't want.

I am not sure why you put a check valve just to the right of the SWG.

That is not an ideal location for the vacuum breaker valve. You want the vacuum breaker at a local high point, for example at the high end of the pipe feeding the bottom of the panels.

 

[chem geek]

You can see where a check valve is typically located in this post which has a nice automation that looks like a source of your diagram.

Richard

 

[el_steak]

You need a check valve after the filter. Without it the pump and filter will drain, which you don't want.

Will the filter and pump drain because of the vacuum break valve? or do you typically have this check valve on all setups?

I am not sure why you put a check valve just to the right of the SWG.

Good point. I simplyfied the diagram, there's actually an electric heater just before the SWG. The check valve is recommended by the manufacturer to avoid back flow of highly chlorinated water in the heater.

 

[el_steak]

You can see where a check valve is typically located in this post which has a nice automation that looks like a source of your diagram.

Yep, I used that as the source of my diagram (modified in good old MS-Paint).

I've done most of the plumbing last fall but forgot the check valve after the filter. I just wanted to make sure it was needed before cutting the pipes. It seems to be.

 

[el_steak]

Check valves...

Looks like I'm going to add that check valve.

Do you guys know if there are different designs for check valves?

I find that the ones I have don't have much travel in the spring and seem to be very restrictive. There's a hissing sound produced water goes through them.

 

[tphaggerty]

Here is what I see:

1) You do need a check valve where you have the question, you don't need the other 2

2) I would move the 3 way to where you have the first T. Move your balancing valve after the 3 way. Otherwise, your balancing valve ALWAYS affects your flow, whether the solar is running or not. On your diagram, when the 3 way is "Not solar", the water still has to go through a bunch of 90s instead of straight through. Unless you really know you need it, you don't have to have a balancing valve.

3) I like having valves to isolate the solar, though there is a risk of preventing water flow as noted before. But, having the valves allows you to work on the solar while the pool remains open if needed.

My setup is as you diagrammed with the changes I mentioned above, less the balancing valve. Works great. If you have a 2 speed or multi-speed pump, you can use the solar controller to kick the pump up when solar is called and off when just filtering, makes for a really quiet pool most of the time.

 

[JasonLion]

There are several kinds of check valves. I like the Jandy check valves. They have very low resistance to flow and can be opened for cleaning if they ever get jammed.

A simple pool setup doesn't have any check valves.

The vacuum breaker valve lets air into the system. If the pump/filter are above pool level the air intake will allow them to drain into the pool. That often causes loss of prime on the pump, which can get very annoying.

 

[tphaggerty]

On solar, you must have a check valve before the solar "source" (normally between the filter and the 3 way valve), otherwise, when the pump shuts down the water coming back off the roof can flow back through your filter, back through the pump and into the pool. Especially messy if you have a DE filter (trust me on this one, personal experience!).

One more thing - the 3 way valve needs to be "leaky". They used to make 3 ways that didn't seal completely, now you (or the solar installer) normally drills a 1/2" hole in the valve (inside obviously) when it is closed to the solar side. This lets the input side of the solar drain when the pump shuts off (the GoldLine/Hayward valve and the installation instructions for the solar panels all had some instructions on this).

 

[joenj]

On solar, you must have a check valve before the solar "source" (normally between the filter and the 3 way valve), otherwise, when the pump shuts down the water coming back off the roof can flow back through your filter, back through the pump and into the pool. Especially messy if you have a DE filter (trust me on this one, personal experience!).

One more thing - the 3 way valve needs to be "leaky". They used to make 3 ways that didn't seal completely, now you (or the solar installer) normally drills a 1/2" hole in the valve (inside obviously) when it is closed to the solar side. This lets the input side of the solar drain when the pump shuts off (the GoldLine/Hayward valve and the installation instructions for the solar panels all had some instructions on this).

Agree,,, I only have the above check valve. My two isolation shutoffs are after my 3 way,with the hole for drain down. I have the Fafco panels which allow the lower supply and upper return to connect on the same side. The vac break is on the opposite end of the supply, lower pipe. I'm dealing with a long run with the upper panel about 20-25 feet above the pump.

Joe

 

[el_steak]

Thanks for all the info guys. I also got a reply from my solar panel vendor (Stephen Cumminger from www.heatwithsolar.com) that goes along the same lines.

So to summarize:

1- Eventhough the vacuum break would work were I located it, it would work better if I located it at the high end of the feeding line (left panel, bottom outlet).

2- I need a check valve just after the filter or I am gonna get all sorts of nasty stuff back in my pool and potentially lose prime on the pump. Apparently Jandy makes a nice low resistance check valve.

3- The 2 shut off valves I have are not really needed since I have a 3-way and a check valve. They are already plumbed, so I'll keep them.

4- For the drain-back from the panel to work properly, I have to make sure that my 3-way diverter valve is NOT positively sealing. I bought the valve from the solar panel vendor, so I sent him an email to check on that.

 

[dschlic1]

On my solar installation, I have just a three way valve. It is operated by my automation controller. I set the limit at the solar side so that the valve does not close completely, thereby serving two purposes: turning on the solar panels, and also functioning as a bypass. The bypass amount is adjusted by moving the stop cam on the valve acuator.

Also the solar installer place the air relief valvejust above one of the isolation valves. This seems to work as it appears that all of the water does drain out of the panels. They stated the reason for this is because the air relief valve is about the only item that can go bad, and therefore is in a position for easy access.

 

[el_steak]

On my solar installation, I have just a three way valve. It is operated by my automation controller. I set the limit at the solar side so that the valve does not close completely, thereby serving two purposes: turning on the solar panels, and also functioning as a bypass. The bypass amount is adjusted by moving the stop cam on the valve acuator.

Also the solar installer place the air relief valvejust above one of the isolation valves. This seems to work as it appears that all of the water does drain out of the panels. They stated the reason for this is because the air relief valve is about the only item that can go bad, and therefore is in a position for easy access.

That's pretty interesting. It simplifies the plumbing quite a bit.

 

[tphaggerty]

Also the solar installer place the air relief valve just above one of the isolation valves. This seems to work as it appears that all of the water does drain out of the panels. They stated the reason for this is because the air relief valve is about the only item that can go bad, and therefore is in a position for easy access.

Not sure I can fully visualize this. The relief valve is designed to allow the panels to drain, so I'm not sure why you would place it so the panels don't drain. Maybe I'm misunderstanding. My relief valve started opposite the input on my 2nd story installation, but we wound up moving it down to about 75% of the way up the return line because it was drawing air into the system when the valve was too high. But even where it is located now, it allows the system to fully drain.