Where to find flow meter?

[MNBobcat]

Hi Guys,


I'm ordering parts tonight. I'm trying to find a flow meter that I can install inline which will tell me how many GPMs are being pumped through the primary circuit.

I have a 1 1/4 copper supply line. My entire primary circuit is 1 1/4.

I've been googling and searching for an hour. Can't find where I can buy a flow meter. Can anyone point me in the right direction?

Thanks!

 

[in hot water]

What GPM range?

 

[MNBobcat]

I think anywhere from 1 GPM up to somewhere around 16 - 20 GPM would be about right.

 

[jebatty]

I bought one off ebay, also called a rotameter or a variable area flow meter, with a 20 gpm scale and 1" fittings. Mine is the the Blue-White brand but their are other brands. If you get one, I would recommend also plumbing a bypass around the flowmeter with isolation valves. The flowmeter adds pump head (up to about 5' of head) to the system, so while it gives a fairly accurate reading while it is in operation, if you bypass it the pump head goes down and actual flow is greater.The ideal install would have tappings on both sides of the flowmeter with pressure gauges to get an actual pressure drop. With that you could calculate actual flow with the flowmeter bypassed.

If you go the ebay route, be patient and you can find one with an attractive price. Otherwise they are fairly expensive. BTW, you also can quite accurately compute pump head by carefully measuring your lines, fittings, etc. to determine friction loss at various gpm, and then use the pump curve chart to determine flow with your circulator. Good luck.

 

[MNBobcat]

Hi Jim,

Thanks for the reply (and the email). I was hoping to find something that had a probe that would stick into the stream of water rather than routing the water through a tube. I looked at the site you referenced and it does look like they may have something that would work. It would be nice to be able to unscrew the flow meter and put a plug in its place when not in use. If the meter itself would significantly reduce flow, which it would if it was less than 1 1/4 inches in diameter, then it wouldn't give me a very accurate idea of my GPM otherwise.


I'll keep an eye on ebay, too.