Is there an automation system that can change speeds of a VS pump while running solar

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ping

ping

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Jun 24, 2011
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Long Beach, CA
I want to know if there is an automation system that is capable of reducing the speed of the pump after the solar speed is activated. The reason why I want this option is when solar demand turns on, the pump needs to run at a high RPM to make sure the panels on my roof are fully primed, but once primed the optimal speed can be reduced. An example would be to run the pump at 3000 RPM when solar starts for about five minutes and then reduce the speed to 1700 RPM for the remaining time that the solar is running. If solar is not running then I would like to run the pump around 1000 RPM.

I don't want to use set times to change the speeds as I do that now with my mechanical timers and 2-speed pump.
 
If you have an Intelliflo vsf, you can use flow to control the flow going to the panels.

That way, the panels should receive the correct amount of flow at all times.

If the pump needs to increase the speed to prime the panels, that's what it should do.

If the pump can reduce speed and still maintain the gpm, then it should do that.

You would need automation that can control the VSF.
 
Ping,

On my system 1700 is not sufficient to maintain flow to the roof and good distribution to the 9 panels I have. I run at about 2600 rpm to accomplish that. Each pump and system is a little different. As James says it's pretty easy if you have Intelliflow with a Pentair pump. With a different pump like in my case I just use the signal that closes the bypass valve to also provide a digital input to my Century V-Green pump. Not so elegant but saved me some $ on the installation. As I get to know the flow characteristics of my system I'm optimizing it. Recently reduced low speed to 1600 rpm and still no "low flow" errors on my SWG. High speed was also reduced to 2600 from 2800. Saving a bundle from my previous 3400 induction motor!

Chris
 
At the moment I have a 2-speed pump with mechanical timers for on/off and speed selection so the run time and speed settings are set regardless if the solar turns on or not. I start the day off with 1/2 hour of high-speed then reduce it to low-speed until 11:00 AM, then run on high-speed again for an hour. The solar may or may not run first thing in the morning, but it will be running by 11:00. The panels need the high-speed flow with my 2-speed pump to be fully primed but they don't need that speed to maintain optimum flow. The pool temp works out fine with this setup, but I would like to be able to run even lower speeds than the low-speed setting to extend the run time and save some on electrical when solar is not being called for.

The VSF along with automation sounds interesting, I'll look into it.
 
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Ping,

I think you'll be very happy with both VS and Automation. There are also ways to perform this with a 2-speed pump with automation also. Not saying I'd do it that way since the VS pump will payout in 2 years or less for most pools but it is possible. The right decision for you depends on your situation and preferences.

Good luck and please keep us informed as you evaluate and execute.

Chris
 
With the Omnilogic, you can set the minimum RPM or % (or flow if you have a vsf pump) in the settings for your heater to operate. When the temp of the pool calls for the heater to run, it will automatically call for the pump to run at that setting until the desired temp is reached, then the pump drops back down to whatever it was running at.

Example: I have a heat pump and have my min RPM set for 90%. I normally run my pump at 35% 24x7, and have my heater scheduled to heat to 89 from 9am to 9pm. At 9am, if the temp is below 89, the heater will turn on and bring the pump to 90%. When 89 is reached, the heater turns off and the pump returns to 35%.

It works the same way for solar heat.
 
The question for my pool will be the required speed of the pump to make sure the panels are primed when the solar turns on and then I would like to reduce the speed once they are primed to maintain optimum flow to the panels if that speed is lower than what is required to prime the panels.
 
Ping,

There are many ways to accomplish the control you are looking for. Automation and VS pump that takes advantage of the advanced RS 485 features is easiest and I would have gone that way but I wasn't able to convince Sr Management to spend the $ on my favorite VS pump. It's also fairly easy to do with just a VS pump that accepts digital inputs and/or can use an adapter accomplish this. For example you can use the signal your solar controller uses to open and close the bypass valve can also be used to trigger a speed selection and the same speed can be selected from the gas valve signal. I use both of these for my V-Green motor. You can do the same thing with almost any brand VS pump. In some cases it requires a $200 adapter such as the Intellicom II.

Chris
 

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ping said:
The question for my pool will be the required speed of the pump to make sure the panels are primed when the solar turns on and then I would like to reduce the speed once they are primed to maintain optimum flow to the panels if that speed is lower than what is required to prime the panels.
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Ping,

You should also consider the minimum speed to optimize heat transfer not just the required amount to maintain flow. Solar panels require a minimum flow for this. Maximum heat transfer usually requires liquid side turbulent flow regime; increasing above this doesn't get you more heat transfer and just really costs you pumping cost. You should be able to find the flow requirement in the solar manual and get a close estimate of flow/speed based on your system drop and the pump curve. Then you can tweak it with actual temperature measurements. Using this method I estimate d 2800 rpm to start and I've been able to reduce my speed by 200 rpm. I may be able to go a little slower still.

Chris
 
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I think the original question got lost here, I am curious because I have the same question.

The goal is to have a solar priming speed that is different to the solar run speed. I.e:
- when solar first switches on, run at speed X for 5 minutes to make sure the panels are primed.
- after this time, drop to speed Y, which is a lower speed that achieves the best balance between energy use and heat transfer

At least in my system, X and Y are very different speeds. So my choice with solar on is to either always run at solar priming speed (wastes energy), or always run at solar rated panel speed (doesn't prime correctly).

I have an Easytouch and Intelliflo, but as far as I can see there is no ability to set a solar priming speed.
 
I haven't done this but can't you just program "solar Prime" speed and then just switch to "solar run? *** Edit, I see your point that this couldn't be done since you trigger on temp "call for heat" and there's no way I know of to put a different speed in after a time delay. However I don't think this really maximizes efficiency since you need speed adequate to provide maximum heat transfer which is adequate for the initial prime speed also.*** I slowly reduced my solar speed from 3400 to 2600 which is the speed it takes to meet lift and flow requirements for the panels to maximize heat transfer. I'm not sure I'm at the minimum flow but I believe at least with my set up that minimum flow for maximum heat transfer is adequate to "prime" the panel. If you slow down to a trickle you lose a lot of heat transfer.

Chris
 
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Rlab, you are correct in that was my exact question that I was after.

From my calculations that I have done over the years, the low-speed on my pump is about the optimum for flow for heat transfer but it doesn't fully prime the panels. All plumbing situations are different and my panels are about 1 1/2 stories tall. For most of the summer I don't even need the panels to run at optimum efficiency as the pool stays warm enough as it is.

The variable flow pump might be the answer for me as I would just program the flow for when the solar is called for to be enough to prime the panels. I don't need too much more flow than what my low-speed is right now as there is only a little amount of air in the system when they do prime on low-speed.
 
My pump starts with a prime speed for about 2 minutes each time it starts. But I'm not sure this happens when it just changes speed so if it's already running at low speed then there's a "call for solar heat" and speed increases I'm not sure it primes again. I'll check and report back.
 
I have an Intelliflo and it definitely doesn't reprime when speed switches, hence my issue with solar prime.

I was thinking one solution may be to run a short scheduled program each morning after the main pump schedule is running. Just run 5 minutes at high speed with solar valve open, then close valve so that the panels are "pre primed" ready for when solar heat is called for and the valve opens again. With the main pump running I *think* the panels would hold their prime?
 
If you have a solar valve the panels will not stay “preprinted”. The valve has a small bypass built in which will slowly drain the panels back into the pool.
Im using an intelliflo pump controlled by a Pentair SolarTouch control panel. When heat is called for,and avail at the panels it ramps the pump speed to my preselected 2600 rpm and opens the solar valve. When finished it closes the valve and returns control to the pump’s onboard controller. It’s also a bargain. The solar valve, solar sensor, Water sensor and the control panel came as a kit for under$250. The only thing it didn’t have was the communication cable (that came with the pump). It works like a dream, just set your desired water temp.
 
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I have a very old AquaLogic controller and it will always prime the panels at high speed and then step down to a lower speed if desired. I believe all of the Hayward full featured controllers (AquaLogic, ProLogic, OmniLogic) have this capability. This is an important feature if your panels require a higher speed for priming than for running.
 

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