Dual Single-Speed Pumps to VS Pump - Plumbing HELP!!!!

[DBGaither]

Here is a my introduction..

I want to replace both of these original pumps with a single VS pump. All the information I can find showing conversions are simple 1-old-single-speed-pump to 1-new-VS-pump, but that is not my case!

I have a high-speed pump that pulls from the bottom-drain, the vacuum line or the skimmer, this feeds into the filter and then the spa heater then to the return system.
I have a low-speed pump that pulls from an unknown location and returns to an unknown location, no ties to the filter or heater.

Firstly: How do I identify which suction and return points for the low speed pump?

Secondly: How do I plumb a new VS-Pump with my connections?

 

[Ecoke]

Turn the low speed pump on and go look to where there is flow. Sounds like it is a booster pump for the spa. If you see flow in the spa, It most likely is pulling from the spa drain. If not there...keep looking...it's coming from somewhere and going somewhere...

 

[acamato]

As for plumbing, I would suggest that you get 2 three-way Jandy valves.
Suction Side - tee together (with the valve) the two suction pipes into a single suction for the new VS pump
Discharge Side - discharge of the new VS pump into the Jandy valve, the two outputs of the Jandy valve to each of the existing discharge line.

 

[DBGaither]

Turn the low speed pump on and go look to where there is flow.

The flow is so low I haven't been able to detect where it is coming from or the return. I have ordered some dye for finding pool leaks (in a syringe). So I'll find out very soon how this is plumbed.