How to install a vacuum gauge?

[Blue Fish]

Hello everyone, thank you for participating in this amazing forum. It has been an incredible learning experience for me!

I would like to install a vacuum gauge to help me better estimate my dynamic head and flow rate. I am just not sure how to install it. The gauges I've seen are threaded and I'm not sure how to join them in the pluming just before the pump. Any suggestions? I have about 1 foot of 2" pvc exposed before my pump.

Thanks so much for your help! :)

[catnip]

Babel, I too was interested in measuring my actual suction head and installed a vacuum gauge at the pump inlet. I drilled a hole and tapped a 1/8 inch female pipe thread in the side of the fitting that screws into the pump inlet. I chose to use a 1/8 inch fitting to minimize the structural impact on the PVC fitting. I screwed in a 1/8 inch brass nipple and then a 1/8 to 1/4 inch female brass adapter to match the gauge. If you don't want to leave the gauge permanently installed, just plug the hole with a 1/8 inch brass plug.

P.S. It's interesting to see how the suction head changes as you adjust the inlet valves from the skimmers and drain. You will also see the suction head decrease as the filter becomes loaded with dirt as the flow decreases.

[Poconos]

Welcome to the forum. You threw me for a bit as there is a Babelfish member too. Since you're on the vacuum side it's easy. Wondering if the vacuum gauge has a standard 1/4 NPT thread like the pressure gauges. In any case, you can tap right into the PVC pipe. Play with a scrap pipe first. If you don't have a tap you can just drill a slightly undersize hole in the pipe then use the gauge threads to cut the PVC. Smear some silicone seal or pipe dope on the threads before you screw it in for the final time. I did it with a pressure gauge for an air pressure leak test jig and it held up fine.
Al

[Blue Fish]

[QUOTE=catnip;46814] I drilled a hole and tapped a 1/8 inch female pipe thread in the side of the fitting that screws into the pump inlet. I chose to use a 1/8 inch fitting to minimize the structural impact on the PVC fitting.QUOTE]

Thanks so much for the info. Could you clarify the part about the "1/8 female pipe thread"? is this a pvc fitting that you screw into the hole you drilled?

Thanks again!:)

[Blue Fish]

Thanks Poconos...I didn't know there was another Babelfish here!

I have some practice pipe to screw in the gauge...I'll give it a try.

[catnip]

Could you clarify the part about the "1/8 female pipe thread"? is this a pvc fitting that you screw into the hole you drilled?

I used a 1/8 inch brass nipple (female threads on each end) to screw into the tapped hope in the PVC. But, as Poconos says, you can try tapping a 1/4 hole and avoid the need for a nipple and 1/8 - 1/4 brass coupler.

[Blue Fish]

Thanks Catnip...I think I'll screw it in straight into the pipe...but I'll practice first :)

Do I have to use a "liquid filled gauge" or a "dry" gauge will do the job? http://www.recreonics.com/standard_gauges.htm

Thanks again

[Poconos]

Can't answer the question on which is best but both are cheap. I wasn't even aware of the liquid filled ones until a few days ago when someone posted on this forum. I'd go with the dry and see how it holds up. Just my cheap opinion.
Al

[imfignewton]

If your looking to do a quick check. You could screw it into the drain plug on the strainer pot side of the pump. When your done just screw back in the winterizing plug. ( you may have to use a brass adapter to match the size up but you can buy that at a big box hardware store)

Hope this helps

[Blue Fish]

imfignewton,

This sounds like a great idea...I guess the vacuum inside should be the same same as just prior to the basket right?

I will try this method first to avoid having to make a new hole in the system. I could even leave the gauge in there permanent since I don't have to winterize the pump here in Sac-of-tomatoes, California.

Thanks!:D