Pentair WhisperFlo 2-Speed Pump, Hayward Aqua Plus and Solar Pool Heating

[Hien Nguyen]

I would like to change out my current Pentair WhisperFlo WF-24 single speed pump to a Pentair WhisperFlo WFDS-4 dual speed (Low @ 1725 RPM and High @ 3450 RPM) for energy savings. The current pump is controlled by Hayward/Goldline Aqua Plus automation unit.

The automation unit is also operated the 7 FAFCO Revolution solar panels (4 ft x 10 ft each panel): a) 4 panels are on the roof of first story; and b) 3 panels are on the roof of second story with the solar system vacuum relief valve (VRV) at the highest point. The solar pool heating system is temperature sensor operating system.

Below are information about pump timing and pump speed from the Aqua Plus Operation Manual:

Filter T1 Time
For two speed or variable speed pumps, this setting will be the period of time when the pump runs at high speed. If the high speed and low speed periods overlap, then the pump will operate in low speed during the overlap period.

Filter T2 Time
For two speed or variable speed pumps, this time clock will set the normal time period for filter pump low speed operation. If the filter pump was off prior to the start of this time period, the filter pump will first turn on at high speed for 3 minutes to prime and establish water flow. Afterwards, it will drop down to low speed for the remainder of the programmed low speed time period.

Allow Low Speed
This menu only appears if the pool filter is configured for 2-speed or variable speed operation. During default operation, high speed mode is used whenever the solar heater is on. If Allow Low Speed is enabled, low speed pump operation will be allowed during solar heating except for the first 3 minutes after solar heat turns on.​

I am currently operating my single speed pump at only 4 hours a day during the winter; however, the pump is running between 7-8 hours during the summer because my pool solar is set at 92F. My house electric bill is very high during the summer months. I am planning to run the potential new 2-speed pump at Low Speed at all time, except for manually pool cleaning. Here are my questions:

1. Are 3 minutes of High Speed running long enough to prime my solar heating system?
2. Will I have any air issue with the solar VRV when the pump is at Low Speed running during the solar system is on?​

Thanks in advance for all your help.

 

[mas985]

1. Should be.
2. Yes, if you have a VRV installed on the roof. This will most likely add air in on low speed unless you move the VRV to a lower elevation.


But I hope you are planning to just replace the motor instead of the entire pump.

 

[Hien Nguyen]

Good Evening Mark,

Thank you very much for your suggestion on buying the replacement motor only instead of the entire pump. The total costs of a replacement 2-speed motor plus seal PA-7 kit, black gasket seal plate, diffuser O-rings and impeller washer gasket are only half of the costs of a new entire 2-speed pump.

Please review the below image and provide your opinion or suggestion on the new potential location of solar VRV.

Thanks for your help.

 

[mas985]

The VRV should always go on the supply side (cold side) of solar. The height is about right.

Does your controller support solar on low speed? I think it does but just wanted to make sure that it will prime the panels on high speed and then step down to low speed after priming.

 

[mas985]

Duplicate

 

[Hien Nguyen]

Mark, thanks for your thoughtful comments.

The 2-speed pump motor has been ordered and should be delivered to my house within a week to 10 days. The Hayward Aqua Plus will run the pump in high speed (3450 RPM) for 3 minutes than reduces to low speed (1725 RPM) for the rest of the time when solar system is on.

The FAFCO solar VRV is mounted at the end of the cold water supply line on the second story. I would like the task to be a D.I.Y. job, but I may have to ask the solar installer to remove the VRV unit and cap the line because the second story roof is at a 45 degree slope. Installing new pump motor and solar VRV to new relocation are definitely D.I.Y. tasks.

I have a few questions for the solar VRV replacement:

1. The FAFCO solar VRV unit is 2-inches in diameter (same diameter as the supply line) and 4-6 inches in length. Can I re-use the FAFCO solar VRV at the new location on the cold water supply side?
2. If the FAFCO VRV is reusable, do I mount the unit parallel (upright) or 90 degree to the supply line?
3. Reviewing the TFP forum on the subject of solar VRV, I noticed that other TFP members have smaller solar VRVs in their solar heating systems. Is smaller VRV compatible for the system?
4. If smaller VRV is compatible, please provide solar VRV recommendations.

Thanks for your help.

 

[mas985]

1. You should be able to
2. Some need to installed vertically while other horizontally. But generally, the orientation it should be the same as it is now.
3. You would have to show me what you are talking about but in most cases, any VRV should work.
4. I don't really have any recommendations.

Did the installer by chance use a check valve as a VRV? That I would not do.

Also, make sure you get a Go-Kit for the motor replacement.

 

[Hien Nguyen]

Below is the FAFCO solar VRV for my solar heating system (2 inches diameter and 4-6 inches length). I have verified that the FAFCO solar VRV is installed at the end of cold water supply line on the second story roof solar panels and not a check valve. Instead of removing the solar VRV and capping the line, can I cover the FAFCO solar VRV with duct tape?


And here are other types of solar VRVs that were posted by other TFP members. Notice how much smaller other types of solar VRVs compare to the 2 inches supply line.

I was not aware about the GO-KIT-32 until now; however, I have purchased the seal PA-7 kit, black gasket seal plate, diffuser O-rings and impeller washer gasket individually. Thanks for your help.