Hayward TriStar Flow

[mattwm]

Hey -

So new pool equipment installed and trying to figure out why my flow is lower than what's listed in the pump's spec. I have a 30x15 AG pool with the Hayward DE4820 filter and Raypak 6450ti heat pump. 2" plumbing, no street elbows. No air in chamber when pump is priming (3450 rpm).

Also installed is the FlowVis meter Amazon.com : FlowVis 2 x 2.5in. Complete Pool Flow Meter and Check Valve : Garden Outdoor

At full speed (3450 rpm) I'm getting around 60-65 gpm with a filter pressure reading of 22 psi. According to the pump spec, I should be up around 100 gpm @ 50 tdh (22 x 2.3).

Flow appears to be more accurate at lower speeds. Roughly 35 gpm @ 2250 rpm and 12 psi (28 tdh).

I suppose the flow meter could be off.. that is the only thing I can think of. My heat pump can't see anything greater than 80 gpm which is a concern.

If anyone has any experience with this or suggestions I'd appreciate some input. Thanks!

 

[kadavis]

What model Tristar do you have?

 

[JamesW]

22 is only the pressure side head loss. You also have a suction side head loss. To get that, you need a vacuum gauge. You can estimate it from the flow rate.

So, the total head loss will be where the gpm meets the curve.

The suction head loss is the total minus the return head loss.

 

[mattwm]

Sorry, thought I was subscribed to this thread and didnt' think I received any responses. The pump is the TriStar SP3202VSP.

22 is only the pressure side head loss. You also have a suction side head loss. To get that, you need a vacuum gauge. You can estimate it from the flow rate.

So, the total head loss will be where the gpm meets the curve.

The suction head loss is the total minus the return head loss.

Thanks. Yea I figured the suction side loss is minimal since I only have < 10 feet of pipe with a few 90's. I purchased a vacuum guage and will install it this weekend to check for total head loss. I will be surprised if it makes up the difference but we'll see. Thanks