Can you see any design flaws in this setup?

[rarara]

Edit: Picture added in post below;

Hi all, relative newcomer to pools here.

As we're coming into summer I have just started checking out the solar segment of my pool setup (recently bought house). The secondary solar pump appears to leak a little after a while and the flow valve doesn't seem to stay open for long which seems to indicate low flow or some kind of pressure issue to me.

Given the previous owners of the house did a lot of poor quality repairs, I am wondering if there is a design fault in the system.

Hopefully this post works, had a few troubles posting so far!

 

[Smykowski]

Welcome!

Low flow usually points to dirty filter which points to bad chemistry. That being said, we're going to need a lot more information to start helping.

First, can you put all of your pool and equipment info in your signature? Second, please post a full set of chemistry test results and tell us how you got them.

 

[JasonLion]

A photo of your equipment pad will also help.

 

[rarara]

Hi again - thanks for the responses. The spam vetting wouldn't let me post the pic initially, hopefully this works.

Its possible that theres some clogging as I had a bad stint with algae last year. The water seems pretty clear at the moment, and the main pump flows ok so if there is a flow issue, I think it would be in the solar segment of the runs only (could be wrong).

My main concern is I'm running 2 pumps, one presumably to deal with the 2 story height to get to the solar heating element, but only a single inlet/outlet. I am wondering if the pumps can work against each other in some situations.

 

[rarara]

No thoughts?

 

[Griswald]

The "T" that is used to pull water into the solar pump is probably where the problem is. Water (all fluids) just don't like to make those kinds of transitions. Also, it could be pulling water from the return, depending on where the least resistance in the system is.

Maybe some type of diverter valve or check valve that would let you pull water only from the filter and not the pool return would help.

 

[JasonLion]

Griswald, that T won't be an issue as long as the main pump is larger than the solar pump and both pumps are working correctly.

rarara, could you describe what is going on with the flow valve in more detail?

 

[rarara]

Im not sure if the main pump is larger than the solar pump. Its certainly not a lot bigger. I'll see if I can read the wattage figures off them.

The flow valve flap opens up fully when you initially turn the solar pump on (main pump already running).
The flap then drops to look about 45 degrees for a short while (10 seconds maybe)
The flab then gradually fades down to looking about the same as when the solar pump isnt running, but it moves around a bit.
Around this point the pump starts to leak a little (maybe too much pressure in the casing?)

Almost seems like it has a burst of life or which then fades out due to too much pressure in the solar segment of the system or something.

Would it make sense to have a check valve in the blue return line, so that the solar return cant flow back into the T section?

 

[JasonLion]

It sounds like something is blocking the flow to the panels. My guess is that water flows in until the panels are pressurized and the back pressure then increases enough to block further flow. Perhaps they are getting air locked, or perhaps there isn't enough pressure to to fully prime them, or perhaps a valve is closed somewhere that is blocking the return flow from the panels. A ball valve can appear to be open but actually be closed if it is broken. The impeller might be partially blocked on the solar pump. Air locks are slightly complex to diagnose.

A check valve is often used on the panel feed line, but it needs to be "leaky". You want water to be able to flow backwards through that pipe when the pump is off so the panels can drain down. Often this is done with a check valve that has a small hole drilled in the flap, allowing only a very slow backwards flow rate.

 

[rarara]

Sounds like a reasonable theory. I think the solar line does actually flow somewhat, but it might be under excessive pressure.

I could feel the warmth in the return line after a while and the temp difference between that and the intake line. When I tried shutting the flow valve a little too quickly after turning the pumps off, there was quite a bit of movement in the solar return presumably due to water hammer like effects. I guess that points to some flow in the solar line.

Unfortunately theres not any pressure gauges to use as diagnostic info

I'll try and get a video of the behavior so you can see what I mean without having to rely on my interpretation.

 

[mas985]

My main concern is I'm running 2 pumps, one presumably to deal with the 2 story height to get to the solar heating element, but only a single inlet/outlet. I am wondering if the pumps can work against each other in some situations.

You shouldn't really need 2 pumps with solar. I was running my solar on a 1/2 HP pump and on a two story house. It doesn't take much pump to lift water 25-30'.

What are the make/models/size of the two pumps?

What is the filter pressure with solar and both pumps running?

What is the filter pressure without solar and and only one pump running?