VF/VS pump & solar heat for panels on 3 1/2 story roof

[stbasil]

Hi y'all!

They are starting gunite as I am writing this, and I am still trying to figure out what I want for my equipment! So, that makes me a newbie! These forums have been a wealth of information and acceleration of my learning curve....

The problem:
I want to plan for solar heat--but panels will be at about 40 feet above pump pad. Considering using SunTouch controller and Intelliflo VF or VS pump. Was hoping to avoid a booster pump for the solar by using the Intelliflo to overcome the 40' static head, priming the solar, then backing off to a reasonable flow rate. However, the Pentair tech that I spoke to on the phone says you can't do that with any of their controllers--you can only have a "solar speed" which is active the whole time solar is active. So I asked if using a VF and just kicking in the solar valve (without "telling" the VF what was going on) would work--hoping the VF would juice up the HP to make up the flow needed for priming the solar panels (since it would try to maintain it's setpoint GPM), then automatically back off after priming. But, he says that sudden change in load would cause an alarm on the VF and it would shut down.

Maybe I am making too big a deal out of this, but it seems like running the pump for many hours of solar heating at the higher speed (the speed that is really only needed for a minute to overcome my static head) would be a real waste of energy, and therefore extra cost.

Some of you folks with similar solar panel heights and/or pump gurus, do you think this is a significant issue, and if so, any suggestions on a controller or a plumbing scheme which would allow such specific speed changes?

Thanks in advance!

 

[ride525]

Bill,

I have a VF but no solar. But I'm interested in your post, as I have a relative with solar, that was talking about replacing his pump.

I was thinking that he could just run a VF with a flow set, and when the solar valves opened, then the VF would just raise the RPM to keep the flow running up to the solar panels. But the comments you received made me realize that this won't work, for a couple of reasons. Either, as Pentair said, the pump will shut off, or increased RPM needs would at least make the VF think the filter was dirty, and the VF would manage flows with much lower flows, which is NOT what you want.

Chem Geek has a VF with solar, so I wonder how he manages this (although probably not 3 1/2 stories).

I don't know enough about Pentair controllers, like Easy Touch or SunTouch, but if you could program one flow (or one speed for VS3050 or VS3050+SVRS) for non-solar, and then the controller knew when solar valves kicked in, and use a different flow or speed for solar, that might work.

Jeff

 

[ride525]

Chem Geek will hopefully see this post and comment, but here is a comment he made last year. He has IntelliTouch controller I believe.

It is true that I don't get as much savings in energy with the IntelliFlo VF when the solar is on, though I do still save some going from what used to be 1840 Watts to what is now 1500 Watts. I get most of my savings when the solar is off going from 1840 Watts to 275 Watts at 26 GPM, and it WILL be off part of each day during the summer as the solar is on only 4-6 hours out of the 8 hour pump cycle and that's keeping the pool at 88F (with a thin opaque safety cover). I also was able to get rid of a pressure-side cleaner booster pump and use the IntelliFlo VF at 15 GPM for The Pool Cleaner. All in all, I cut my electricity cost for pumps in half from around $1400 to $700. For me, it was definitely worth it.

And later in the same thread:

Though I have IntelliTouch in my system, the most important would be the temperature differential controller since that makes the most difference switching a valve to go through vs. bypass the solar system depending on whether the solar would heat the water (i.e. if it's sunny enough). The 4-6 hours I quoted is done automatically. I have my pump start at 9 AM and usually the solar is on by 10 AM unless we have fog in the morning. During the summer, the solar is usually off by 2 PM or 3 PM, sometimes at 4 PM and the pump goes off at 5 PM. The pump on/off is based on time. The IntelliTouch lets me set different flow rates when the solar is on vs. off and that is what saves me the most money.

I don't know if SunTouch will do that for you -- if it can switch between two different programs on the IntelliFlo pump, then that should work -- one program would be set with a flow rate for solar on while another would be set for solar off. Then, the controller would switch both the pump program and a valve at the same time (the valve directs the flow to the solar vs. bypassing the solar).

 

[lightingguy]

I have solar on my VF. It's currently manual though. I thought I had a pretty high rpm change with solar on (260 watts solar off, 530 watts solar on) but Chem's is significantly higher.

I haven't had an issue with it - but dont have a 40' roof and my system is kinda frankenstein-ish at the moment.

 

[ride525]

Lightingguy,

What did you mean, your solar is currently manual? No controller like Easytouch or Suntouch? Do you have to manually change the VF every time you use it for solar daily?

Thanks,

Jeff

 

[lightingguy]

We bought this massive fixer upper so priority management has been a big issue the last couple years and pool stuff has been piece meal.

So I installed the panels when we first bought the house (2 summers ago) - no controllers or anything. Just a couple ball valves to route the flow. I just set the intermatic to 10am to 5pm and turn the solar on when it starts to warm up. Not very efficient but it works in Southern California.

The pump gave up the magic smoke a few months ago and I put in the VF.

So if the pump is on and switch over to the solar - the pump registers the additional head and ramps up accordingly.


I think the issue is trying to determine how much head differential the pump can handle before it chooses to stop working.

 

[ride525]

I first thought the pump might work that way. Starting up without solar, then ramping up RPM and kw when solar is on.

But I was worried that the pump would think the filter needed cleaning (with the extra flow demands) and at the very least give a "Service System Soon" alert, and start managing flow to keep it pressures below the "clean filter pressure", the incremental pressure above a clean filter. I just realized that if you restart your pump after a cleaning, and are in solar mode, that the higher demands of the pump would then be at higher baseline for the clean filter pressure.

Jeff

 

[JasonLion]

Depending on how your solar system is designed/installed, you may or may not be able to run the solar at a lower speed once it is primed. In a typical setup you need to maintain positive pressure at the top of the panels to keep the tubes in the panels from collapsing and blocking the flow and also to maintain enough pressure to keep the vacuum breaker valve closed.

If it will work with your panels, it is possible to program things so the VF runs faster for priming and then slows down for the rest of the solar period, but it requires extra effort programming the controller. You need to setup an extra feature that comes on just before the solar panels prime which switches to a speed (not a flow) and has a higher priority than the standard solar speed and then turns off after 15 minutes or half an hour. It takes some significant programming effort, but it is possible.

 

[stbasil]

Jason, using a feature setting is a good idea, and I think it would work if the solar was on a time-clock function, but it is instead controlled by temperature sensors. So, once the water/ambient temp settings are met, solar kicks in with the solar speed setting, and I don't see any automatic way of then selecting a feature which would override the higher speed. Is that right, or am I missing something? Too bad the SunTouch doesn't have a contact closure-type input which could be used to trigger a feature, but it only has temperature sensor inputs. If it did, then I could just have a 15 minute time-delay relay which was triggered by the solar valve signal, and use its contacts to trigger the "feature" to switch to a lower speed.

This morning, at the suggestion of my PB, I contacted a technical rep for Pentair who is in Texas, and who has a lot of experience with solar. He says the way for me to do solar heat with the SunTouch is to use a VS pump and pick a speed for the solar mode which will allow those high-up panels to prime, but won't be too wasteful on energy--he says it is not possible to automate a slower speed after the panels are primed. At least I can do it all with the VS, and not have to use a booster pump for solar.

The neat thing about the VS is that I don't have to guess about pump sizing for this installation, especially since I will probably not install the solar until next season.

So, I my thinking right now is to install the SunTouch and let it control the IntelliFlo VS, IntelliChlor SWG and the Polaris booster, as well as manage freeze protection. Then, I can add the solar next year if I want to. Please chime in if anybody has any better ideas, cause I've got to tell my PB what I want for equipment in just a few days! BTW, he said he would match the internet pricing for what I specify.....sounds good to me!