Optimum VST Pump Speed for Heating and Maintaining?


New member
Jan 9, 2021
Waynesville MO
We had an in-ground fiberglass pool that we open year-round. in South West Missouri. Yes, it is covered when we are not using it (solar cover). We have Pentair Pool Equipment. We have a Pentair Master Temp 250 Heater and we just replaced our Whisperflo W4 single-speed Pump with a Pentair Superflo VST.

What is the optimum pump speed for heating (raising the temp), and for maintaining the temp? Higher or Lower? I have seen many varying opinions.

Since we keep the heater on 24/7, I am trying to figure out the best Pump speed for both efficiency, filtering, and heating. We use a pool robot, so never use any suction vacuum.

The old one ran steady at 3450. The heater will run at low flow rates like say 1400, as it has a switch just in case the flow is too low or stops. Right now it is at 1900 for 2400 hours

I was thinking higher was better for both heating fast and maintaining, but I have seen no definitive answer? I have seen low speed is better for both. I have seen low speed is better for electrical, but not for heating, which still saves more.

Can I get a little help?

Thank you.


Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

The whole purpose of a VS pump is to run at as low a speed as you can, and still get the job done.. I would run at about 100 or 200 RPM above what the heater needs to heat.


Jim R.


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
The heater puts out a fixed amount of BTUs into the water regardless of flow. The pool will get the same amount of BTUs over time with low flow or high flow. You will feel the water temperature difference with the return water being hotter with low flow then high flow. But to the pool the amount of heat added is the same.

I would run your system at around 1600 rpm.
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