Aqualink re-prime on Solar?

Not directly.

But pick a time period when solar is likely running in the morning. Set a schedule for the pump to run at 3400 rpm for a period of time to catch the solar panels running and purge all the air.

Maybe @Dirk who has experience with Solar with an EasyTouch has other ideas. The way the Aqualink and EasyTouch work with solar is similar.

Hmm, my panels don't trap air, but then I went to great lengths positioning them so they don't. It was a matter of skewing the angle of the panels relative to the roof's slope so that there is a low and high corner. I'd have to see more of your system to advise further (pics).

If the flow through you panels is not optimal, flushing them with high flow to eliminate the air might not solve the real problem. If your panels are not positioned correctly, they won't heat as efficiently (not just trap air). See this page for some diagrams that illustrate what might be going on (study the second animation):


Or it might be a matter of where your vacuum relief valve is located.

How many stories high is your system?
Where is the vacuum relief valve located?

Maybe @mas985 has some ideas.

Dave95602 said:

Wondering if it is possible to have my pump run at priming speed for a few minutes when our Aqualink calls for solar?

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Some controllers do this, mine does. When solar engages on my system, the RPM goes to maximum speed setting and then after 3 minutes goes back to the regular setting. However, I am not sure about yours.

Dave95602 said:

Reason: Pump rpm required to "prime" the solar system (push water up to roof and force out all the air) is higher than the rpm required for the flowrate that my solar panels call for once the system is flushed of air (steady state rpm).

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That is normally the case. Most likely the panels are fully primed but the return pipe requires extra flow rate because you have to push the air downwards through the pipe and air wants to rise in the water column so there is a critical flow rate for this to happen (>1 ft/sec).

However, If the flow rate is sufficient for purging of this air but still does not occur, then the pressure at the VRV may not be high enough to seal allowing air to continuously enter the system. Both are critical for purging all the air.

Dave95602 said:

Scenario: Filter cycle starts at 8am and the pump primes, then drops down to filter speed. At, say, 10am, the air warms and the Aqualink calls for solar heat - diverter valve directs flow to panels and pump rpm increases to the steady state solar speed. But some air remains in solar loop.

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What is the RPM and filter pressure for each of these modes? If your controller does not support a priming mode, one change would be to start the pump when you know it will immediately call for solar.

And these two:

Dirk said:

How many stories high is your system?
Where is the vacuum relief valve located?

Click to expand...

Dave95602 said:

Wondering if it is possible to have my pump run at priming speed for a few minutes when our Aqualink calls for solar?

Reason: Pump rpm required to "prime" the solar system (push water up to roof and force out all the air) is higher than the rpm required for the flowrate that my solar panels call for once the system is flushed of air (steady state rpm).

Scenario: Filter cycle starts at 8am and the pump primes, then drops down to filter speed. At, say, 10am, the air warms and the Aqualink calls for solar heat - diverter valve directs flow to panels and pump rpm increases to the steady state solar speed. But some air remains in solar loop.

I have a newer Aqualink RS-P4 (pool only) with a iAqualink 3.0, installed in 2022, that controls our solar. Just one variable speed pump runs filter, solar.

Thanks, Dave

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Shouldn't be any air in the solar once the panels fill. If you are continually getting air into the pool, your filter is dirty or the RPM too slow. That will allow the water to fall from the roof faster than it is supplied. That opens the vacuum relief valve and sucks in air. This is especially true if it is a two-story house. See it all the time. If the filter is clean, you find a speed where that doesn't happen, add about 100-200 RPM for a dirty filter, and you will be fine. Its the nature of a VSP and pool solar. If, after you get it set up this way, it starts again, you know its time to clean the filter.

Dave95602 said:

Mark - I'm guessing your not using an Aqualink controller? I've not found a way to trigger the higher rpm when it calls for solar. I've read as much info on the Aqualink as I can find, and watched some vids, but still no luck.

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I have the Hayward AquaLogic controller.

Dave95602 said:

I think your comment "return pipe requires extra flow rate because you have to push the air downwards through the pipe and air wants to rise in the water column so there is a critical flow rate for this to happen" may be the issue here. After I manually prime at higher rpm, the flow through the solar pipes is almost silent. But when there is no prime, I can hear water falling down the vertical pipe runs on the return and the flow rate is lower. Since there is no column of water dropping on the return side to help offset the lift on the supply side, the flow rate stays much lower, and does not flush the air.

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How high are the panels installed?

Where is the VRV installed?

What is the filter pressure when the solar valve is engaged and at solar RPM?

You might have missed his answers:

mas985 said:

How high are the panels installed?

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The top of the array is ~12' above the surface of the pool

mas985 said:

Where is the VRV installed?

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the VRV is about half that height on the return

mas985 said:

What is the filter pressure when the solar valve is engaged and at solar RPM?

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After priming, I can run the pump at 1700 rpm with good flow and not have the VRV open, this is where I would like to run. My pump primes at 2750 if I recall correctly, and at that rpm it clears all the air in a minute or two. My filter was just cleaned, psi is under 5 at 1700 rpm and still under 10 at 2200 rpm.

I did miss the responses, thanks.

VRV location should never be lower on the return pipe. Pressure is much lower there to keep it closed so it will probably leak air into the system. If you want to run on lower RPM, it should be on the supply side lower than the panels. This is closer to the pump and at a much higher pressure.

My filter was just cleaned, psi is under 5 at 1700 rpm and still under 10 at 2200 rpm.

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During the priming phase and with a 12' lift, pressure needs to be at least 5 PSI but that does not account for the pressure loss in the plumbing so you would want at least 7 PSI if not a little more or the system will never fully prime.

As I mentioned before, you only need about 1 ft/sec to flush the return pipe in less than a minute. With a 2" pipe that is only about 10 GPM.

So I believe your problem is related to the location of the VRV valve and the RPM used for solar.

Dave95602 said:

Ok, I misspoke, the VRV is on the supply side about 6' below the top of the panels. Sorry for the confusion.

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Ok, that is fine and should not be part of the problem.

Dave95602 said:

Back to the original question, no way to configure our Aqualink to run the pump at priming speed for a few minutes when it calls for solar?

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Not that I can see. It is odd they do not provide a mechanism to up the speed while the panels prime. You might call Jandy and see if there is a hack around that issue.

But it is an easy fix if you just up the RPM a bit. I know it costs more to run the pump but probably not that much more. Which Jandy VS pump do you have?

Priming is a function built in to the pump, not a function of the Aqualink. It happens each time the pump re-starts only.

So with that pump and an estimate of the plumbing you might have, I get a filter pressure of around 5 PSI at 1700 RPM & 9.6 PSI at 2200 RPM so not too far off from what you have. Energy use at 1700 RPM would be around 300 watts and almost double that at 2200 RPM.

However, at 1800 RPM, the panels should have positive pressure and the lift should be sufficient. This would be about 6 PSI filter pressure and the pump would run at 350 watts so 50 watts higher which is not all that much.

Have you tried 1800 RPM instead of 1700 to see if that is enough for priming?

I'm going to predict that once your FlowVis helps you determine the optimum flow rate for your panels, which will then determine your RPMs, those RPMs will solve your priming issue. Here's hoping, anyway.

Here's a far-out idea, with absolutely no track record behind it (I never tried it, nor heard of it before). I don't even know if it would work, but it would be easy enough to test, at virtually no cost.

You could set up one of your pool automation relays to interfere with the roof temperature sensor. I'm not exactly sure which, but the relay would either short the temperature sensor, or add a resistor to its wire (we can figure out which), which in essence would fool your pool automation controller into thinking the roof was hot enough to heat your pool, even when it isn't.

Then schedule that relay to close for ±5 minutes at the exact start of your pump runtime.

Then schedule your solar heating also at the exact start of your pump runtime (I'm guessing you already have it scheduled that way, as I do).

At pump startup, the pump would be at prime speed, and the controller would be calling on the solar valve to engage the solar panels, because it would think there is available heat on the roof. That would prime/purge your panels.

After five minutes, the temp sensor "fooling" relay would disengage, and then the controller would see the actual temp on the roof, and either continue to heat the pool if the real roof temperature supported that, or shut down the system until the roof was ready. But the panels would retain the water, because (assuming your solar valve is correctly plumbed), the water wouldn't drain down off the roof until the pump shut down for the day. That way, your panels would be already full of water when the solar heater is called for real.

The downside would be: you'd have a large slug of pool water on the roof cooling off in the morning hours until the sun heated it up. It's hard to say, but I doubt that would lose you that much overall heating in the pool over the course of a day. And you could program the start of this "pre-priming" so that the water wouldn't typically sit up there all that long.

This idea was inspired by a different suggestion I almost offered. Some solar panel arrays are located below the level of the pool's water level, like when there is no available roof space, and a ground array is the only option. They remain full of water 24/7, as they cannot gravity-drain back into the pool each night. So that is a thing. I was almost going to suggest you could rig your plumbing so that the panels never drain, so would never need to be purged of air. But this has a lot of disadvantages, so the "fooling" relay idea is a somewhat better compromise of that initial idea.

I'm counting on @mas985 to shoot holes in either idea, should either be crazier than I'm imagining.

Hopefully, your RPM experiments will solve the problem, but if not, maybe this somewhat radical approach could work.

Just seems easier to start the pump a little after the sun first hits the solar temperature sensor so they both start at the same time. No reason in my mind to start it any earlier anyway. This is what I do with my system. If you need extra run time, put that at the end of the cycle instead of the beginning.