replacing 1hp pump with 1hp whisperflow 2 speed.

[mdhwoods]

Just out of curiosity will the 2 speed have to be on high speed when pumping through the solar panels on the roof? or will being in low be enough? The solar panels are on quite a bit in the summer due to the trees around the pool so if it will need to be on high there is not much of an advantage going 2 speed. I know when running my baracudda it will need to be on high.

Thanks

 

[cubbybeave08]

Just out of curiosity will the 2 speed have to be on high speed when pumping through the solar panels on the roof? or will being in low be enough? The solar panels are on quite a bit in the summer due to the trees around the pool so if it will need to be on high there is not much of an advantage going 2 speed. I know when running my baracudda it will need to be on high.

Thanks

I think it kind of depends on how high and how far away the pump is from the panels. You may need to have 1.5 to 2 HP...I am not an expert on this, but I know you need to take all that into account.

 

[mdhwoods]

right on the roof above the pump and filter.

 

[PoolGuyNJ]

Yes, it will need to be on high speed if the solar is installed with a vacuum relief and to get the water moving through the panels at the right speed.

The vacuum relief valve will bleed air in the panels when they are filling, closes when full and allows air in to drain the panels when the pump is off or the source water is turned off due to the desired temp having been reached. This ensures the water in the panels never gets to boiling when the flow stops, which would generate steam and pressure, potentially causing a failure in the panel's integrity.

Scott
PoolGuyNJ

 

[mas985]

If the vacuum release valve is installed on a two story roof, then you will not be able to run solar on low speed. If it is installed above the pad by a few feet then you probably could run on low speed. But low speed heat transfer will be less than on high speed so that also needs to be taken into account.

 

[mdhwoods]

If the vacuum release valve is installed on a two story roof, then you will not be able to run solar on low speed. If it is installed above the pad by a few feet then you probably could run on low speed. But low speed heat transfer will be less than on high speed so that also needs to be taken into account.

Its a single story house with the panels being on the roof right above the pad and the pad being at ground level. If I remember correctly there is 7 or 8 panels. The inlet to the panels has a vacuum relief as i can hear it allow air in when the system is off. The panels are controlled automatically via a control panel.

Wouldn't the water heat up more on low speed causing a higher temperature at a lower flow? So the water would be hotter just not circulate as fast.

Thanks

 

[PoolGuyNJ]

You'll get a lot more BTUs into the pool on high speed. While the temp of the water may increase a little on low speed, the low volume of water passing through the panels will not make up the difference.

I also doubt the vacuum relief will seal on low speed on a reliable basis resulting in water escaping and draining out of the pool and into the roof's gutter. As the valve ages, this would happen more frequently.

According to the info I have, at 20 ft of head, at low speed, you'll only get 20 gallons/min. I would be willing to bet that the pump would have less flow than that with the load of the solar panels generating at least that much resistance to flow. That low of a flow will not be adequate.

BTW, Hi Mas!

Scott
PoolGuyNJ

 

[mas985]

Its a single story house with the panels being on the roof right above the pad and the pad being at ground level. If I remember correctly there is 7 or 8 panels. The inlet to the panels has a vacuum relief as i can hear it allow air in when the system is off. The panels are controlled automatically via a control panel.

Wouldn't the water heat up more on low speed causing a higher temperature at a lower flow? So the water would be hotter just not circulate as fast.

Thanks

Solar panel efficiency drops with flow rate. So the slower the water moves through the panels, the less BTU/MIN is transfered to the water. Heat transfer is proportional to the temperature difference of the materials, the higher the better. The water may be hotter coming out of the panels on low speed but it is not twice as much as high speed which it would need to be in order to compensate for the reduced flow rate.

However, sometimes the heat transfer at low speed is good enough so it may still be possible. With a 1 HP Whisperflo, the vacuum release valve probably cannot be installed more than a few feet above the pad to work properly on low speed. How high is it?

 

[mas985]

I also doubt the vacuum relief will seal on low speed on a reliable basis resulting in water escaping and draining out of the pool and into the roof's gutter.

BTW, Hi Mas!

Scott
PoolGuyNJ

Hi back. Glad to see you made it over here.

Also, if there is enough pressure on the vacuum release to cause water to come out, I would think that it should seal but it probably depends on the valve design. I am aware of a few installations where it seems to work on low speed but in every case, the vacuum release is installed less than 8' above the pad. The lower the HP pump, the lower the valve installation needs to be. However, I usually only recommend installing the valve at the highest point of the panels to make sure the panels drain properly.

One of the advantages of a VS pump over a two speed is that you can set the optimal speed for both solar and energy use.

 

[mdhwoods]

How high is it?

it sits right under the over hang, so 6'6" give or take a bit.

 

[mdhwoods]

One of the advantages of a VS pump over a two speed is that you can set the optimal speed for both solar and energy use.

I know but at twice the cost can I justify it. If i was to use a variable speed would it automatically increase the flo rate when the solar panels turned on and decrease it when they went off? Or do i have the buy that addon controller to do that?

I wonder if i could design a circuit that automatically switches the 2speed to high when the solar panels turn on. The solar panel control outputs 24v to turn on the valve, so maybe tie that to a 24v relay which would switch the 2 speed to high.


Thanks for all your help guys. I am glad i didn't just rush out and buy the 2 speed.

 

[mas985]

6' 6" is low enough where it might just work on low speed. I might be able to figure out for sure if it will work but I need to know what the pressure reading on the filter is with and without solar for your current pump.

If it does work, you could always run the pump on high speed when you want optimal heating and run it on low speed when you don't need so much extra heat.

Another option you might consider if your current pump is in good condition, is to just replace the motor with a two speed motor. This will be much less expensive and still give you fairly good energy performance.

 

[patf11]

Last year our electric utility was offering $200 rebates to change to 2 speed pool pumps. Rebate was good for complete pump or replacement motor as Mark suggested.

If my memory is correct, cost for motor and relay needed to control speeds was about $300. So with rebate net was $100, payoff about 6 months near as I can figure.

We have solar setup much like you describe and we do need to run on high speed for solar but rest of time low works great.

Might be worth while to see if local electric utility offers any rebates.

 

[mdhwoods]

Last year our electric utility was offering $200 rebates to change to 2 speed pool pumps. Rebate was good for complete pump or replacement motor as Mark suggested.

If my memory is correct, cost for motor and relay needed to control speeds was about $300. So with rebate net was $100, payoff about 6 months near as I can figure.

We have solar setup much like you describe and we do need to run on high speed for solar but rest of time low works great.

Might be worth while to see if local electric utility offers any rebates.

When the solar turns on does it automatically switch to hi?

Thanks

 

[patf11]

Pump speed is controlled by automation control system. Runs on high for first three minutes of a timed cycle and/or when the automation system activates solar heat. Low is activated when hi is not required.

My automation system is homegrown but I believe just about any pool automation control system and many solar control systems can control pump speed.

 

[mdhwoods]

Pump speed is controlled by automation control system. Runs on high for first three minutes of a timed cycle and/or when the automation system activates solar heat. Low is activated when hi is not required.

My automation system is homegrown but I believe just about any pool automation control system and many solar control systems can control pump speed.

i will have to look into my solar control and see if it can do that. It is automated and controls a 24v Jandy valve. i suspect worse case i could design a 24v relay circuit that turns the pump on hi when it call for solar.

 

[mdhwoods]

So I ended up buying a whisperflo 2 speed 1.5hp pump. I contacted Heliotrope HelioMatic the manufacture of my solar controller as they have 2 models, one that will put the pump in hi when calling for solar and one that doesn't. They are kind enough to take my 4000 controller which doesn't support this and upgrade it to the 5000 for $50.00. This is not the first time I have dealt with Heliotrope for help and i can tell you they are top notch. $50.00 to take my 2 year old controller and give me a new one is not something many manufactures would even think of doing. Spent weekend removing all of my old equipment and getting rid of the preformed pad. Framed and poured a 5x2x4" concrete pad and re plumbed all the plumbing and fixed a small leak in the t where the vacuum breaker is for the solar by replacing the 1.5x1.5x1.2" t and then from the t to the solar inlet.

Pump showed up today so when i got home I plumbed in that side and wired it up. Was pretty excited to turn it on as i have not had the pump running normally for 2 weeks and at all for 3 days. Only thing I noticed is that i will have to bolt it to the slab as when I switch from hi to low it tends to buck slightly from the dramatic slowdown. Thats a weekend project.

What really amazed me is that I have not run the pump in 3 days nor added chlorine for 4 and because of the cooler water temperatures my level was still at 4 when i finally got the pump turned on and running.

Now that this is all done I am curious if I will need to run the pump on low 24x7, or during the winter when the pool is not used can I run it for only 12hrs? Any input on this would be appreciated.