Flow rate Pentair VS

tcat

Silver Supporter
May 30, 2012
911
Austin, TX
Is there an easy way to get an idea of flow rate at various pump speeds? I have a heat pump that kicks off around 35 or 40 gpm. Last year I had no problem running at 1500rpm. I got a new board for the HP because the display burned out, but now I need to run the pump at 1900 rpm to keep the HP going. Must be the new board (5 years newer), although could be filter getting dirty over the winter, but never shut off in the past with dirty filter. Just need to figure out if maybe a sensor in the HP is defective.

Typical in ground pool about 50 feet from pump pad, 2" piping, DE filter.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,016
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
When was the last time you completely disassembled the DE filter and cleaned it? What is your current filter pressure versus your clean filter pressure?
 

Pool_Medic

In The Industry
Apr 1, 2018
1,441
Bangor Maine
The speed that works on a clean filter will need to be bumped up after said filter collects dirt and slowly reduces the flow to the heat pump. Very easy to do really.
 

tcat

Silver Supporter
May 30, 2012
911
Austin, TX
Cleaned filter last August (full teardown). Filter is at 22psi at 2600rpm, about 15psi at 1700. What's strange is in the morning it's fine at 1700, but after lunch (hot sun hits it), it stops and I need to crank it to 1900 to get it going again. I'll backflush tomorrow, see how that looks. Just odd it's run for 2 years at 1450rpm with no issues. Gulfstream said nothing has changed and recommends 45 gpm flow rate.
 

Pool_Medic

In The Industry
Apr 1, 2018
1,441
Bangor Maine
It’s possible the flow switch inside the heat pump could have issues. When I set up a heat pump with a vs pump, I dial it the speed the heat pump likes, then I adjust it up 200-400 rpm.

I also have everyone of my pools adjusted to dial the pump down at night when it’s cooler out, zero sense running a heat pump when ambient temps are below 60
 

tcat

Silver Supporter
May 30, 2012
911
Austin, TX
It’s possible the flow switch inside the heat pump could have issues. When I set up a heat pump with a vs pump, I dial it the speed the heat pump likes, then I adjust it up 200-400 rpm.

I also have everyone of my pools adjusted to dial the pump down at night when it’s cooler out, zero sense running a heat pump when ambient temps are below 60
Yeah, I only run it from 9am to 7pm. Do flow switches go bad (5 years)?