No flow in pool returns. What happened?

[Charlie227]

Solar heat on. Panels on two story roof.

I was swimming in my pool this morning when the VS pump was running at 2200 rpm. Everything fine. When the VS reduced to the 1800 rpm schedule, water flow ceased in the returns. I got out and checked the equipment and the pool pump pressure increased 10 psi. My SWCG was covered so I don’t know if it showed a no flow condition. I switched the solar off, the filter pressure returned to normal, and flow was restored to the returns. This was the first time I ran the solar in awhile as the water isn’t all that cold in the mornings. I only wanted to run the solar for a few hours for a small warm up.

What do you think happened?

 

[ajw22]

Did you try increasing your pump speed back to 2200 rpm with the solar on?

Check if your filter needs a cleaning.

Your flow slowed down at 1800 rpm. You had flow, just hard to feel it out of the returns.

 

[Charlie227]

Did you try increasing your pump speed back to 2200 rpm with the solar on?

Check if your filter needs a cleaning.

Your flow slowed down at 1800 rpm. You had flow, just hard to feel it out of the returns.

Thanks Allen. No I didn’t increase the speed. Filter was just cleaned a week or so ago. That’s the interesting part. Usually, the filter pressure is very low to nothing at 1800. It was at 15 psi until I shut the solar off, then hardly noticeable.

 

[ajw22]

You sure a valve was not partially closed in your solar system?

 

[JamesW]

At 1,800 rpm, if the pressure is 10 psi, the flow will basically stop. At 1,800 rpm, it's not going to be able to produce enough pressure and flow to get to the roof. The water will just get struck in the pipe going to the roof.

You're probably going to need about 2,600 rpm to provide enough flow when on solar.

 

[Charlie227]

You sure a valve was not partially closed in your solar system?

That could be a possibility. The valve looked ok externally.

 

[Charlie227]

At 1,800 rpm, if the pressure is 10 psi, the flow will basically stop. At 1,800 rpm, it's not going to be able to produce enough pressure and flow to get to the roof. The water will just get struck in the pipe going to the roof.

You're probably going to need about 2,600 rpm to provide enough flow when on solar.

Does that mean no flow to the returns? What about the 15 psi filter pressure? I wasn’t having any problem at 2200 or 1800 previously in the early summer.

 

[JamesW]

For the SuperMax VS Variable Speed Pump, at 1,800 rpm, the flow goes to zero at about 8.5 to 10 psi. At 2,200 rpm, the flow goes to zero at about 13 psi.

I don't think that your 2nd story solar will work at 1,800 rpm at all. If the roof is 23 ft high, the water will not make it. The flow will go to zero.

At 2,200 rpm, the pump can do about 30 feet before the water stops. Depending on the height of the roof, you might get 30 to 40 gpm at 2,200 rpm.