Flow Meter for Heat Pump

rmundo21

Well-known member
Jun 30, 2015
48
Hagerstown, Maryland
I am getting ready to install a Hayward 140k btu heat pump which calls for a bypass valve set up for pumps over 3/4 hp and a max flow of 75 gpm. Since my Tristar vs pump is rated as 2 hp and 80 gpm at max speed and it would be a good idea anyway to bypass the heater if it had to be taken off line, I was going to use Jandy 2 way valves to make up the by pass. My question is measuring the flow for optimal performance. Can a Flowvis be installed on the heater output since it calls for a check valve before the SWG anyway or is the flow reduced as it travels through the heat pump and not the same gpm as it enters? I would install a Blue-White flow meter on the input side, but the install instructions say not to install in direct sunlight which is puzzling since they are geared towards pools. Thanks for your help.
 

KellisEM

Active member
May 17, 2017
25
Des Moines, IA
Flow, is flow regardless of where in the line it is measured. It is pressure that will vary. Just be sure to follow the minimum distances for your flowmeter and you should be fine.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
34,348
Sebring, Florida
The Flow-vis meter doesn't have the minimum distances as blue-white and is guaranteed accurate. You can get them @ Tftestkits.net
 

ps0303

TFP Expert
In The Industry
Jul 6, 2011
4,049
FL
Do as you wish but honestly, a flow meter is just another thing to fail. The only time I ever see a flow meter is on commercial units, never in a residential setting.
 

Patrick_B

TFP Expert
LifeTime Supporter
Jun 7, 2011
15,004
Midland TX
These really are pretty good Paul. I've seen just about every kind there is in the industrial world, and these are simple and very reliable. They really are no more than a Jandy spring/flap check so they are reliable as any of those are. For that, I don't have the knowledge of experince. I have no doubt you've seen plenty more things afield than I, but my FloVis is going on season 4 with nary a problem. I installed mine just upstream of pump suction, so nowhere near the heater in/out.
 

rmundo21

Well-known member
Jun 30, 2015
48
Hagerstown, Maryland
Are there any other ways to measure the flow rate? I figured I would adjust the bypass valve to get the "ideal" flow rate to the heat pump. I know Hayward specifies it in th owners manual, but I don't have it in front of me. I also know the max flow rate of my pump at 3450 rpm is 80 gpm which I usually use when vacuuming, but I wouldn't know how much flow to divert to make the hp happy.