Installing a Vaccum Gauge...

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T

TANEAL1

0
Aug 3, 2015
35
Orlando/Florida
I'm having "priming" issues and have checked everything possible to find the problem without success. I'm planning on installing a Vacuum Pressure gauge in either the inlet pipe just ahead of the pump itself, or screwing the gauge into the 1/4" drain located below the pump inlet basket.

It should be easier to just screw the gauge into the drain fitting than to install it into a PVC pipe, but for troubleshooting purposes, is one of these locations "better" than the other?

The gauges that I've found online all appear to have a 1/4" fitting. Is this the only size fitting available?

Thanks to any responders!

Tom
 
I would say it makes no difference. My Caveat is that I will defer to anything mas985 says on the subject.

So I believe you will get a different value if you place it on the drain plug as opposed to back towards the skimmer. I also don't believe it really matters because what you typically use these gauges for is to mark any changes you see in the value, rather than the specific value.

i.e 4.7 at the drain plug is not very meaningful until it changes drastically to another number.

I can't see how it will possibly help you locate a priming issue. Have you read this article in Pool School Pool School - Suction Side Air Leaks
 
thepoolman said:
What are you looking to accomplish with the vacuum gauge?
Click to expand...

I need to replace the section of pipe that leads directly to the pump intake anyway, so if this is the best location for it, this is the easiest time to add it.

Questions I'd like the gauge to answer:

1. Am I getting enough suction to prime the pump?

2. How does the vacuum pressure I'm getting with EACH of my 3 inputs selected compare with the other two?

I've run out of stuff to check, so I figure I may as well try this...

Tom
 
duraleigh said:
I would say it makes no difference. My Caveat is that I will defer to anything mas985 says on the subject.

So I believe you will get a different value if you place it on the drain plug as opposed to back towards the skimmer. I also don't believe it really matters because what you typically use these gauges for is to mark any changes you see in the value, rather than the specific value.

i.e 4.7 at the drain plug is not very pertinent until it changes to 5.8

I can't see how it will possibly help you locate a priming issue. Have you read this article in Pool School Pool School - Suction Side Air Leaks
Click to expand...

Hi Dave,

Thanks for you diplomatic response regarding mas985.

Yes, I've read this article, and many, many others. I've tried absolutely everything mentioned and find no problems with tightness of connectors, O-rings, J-valves, joints, etc.

My Pentair VS is only 1 1/2 years old. With one end of a 1" clear plastic hose attached directly to the pump input and the other end in the pool water the pump sucks all of the air out of the hose and pumps enough water to keep the input basket full within 45 seconds after starting the pump.

I've constructed adapters to allow attaching my garden hose to the vacuum cleaner, skimmer and spa drain at the pool end of these input pipes. At the moment, my 3/4" garden hose is attached to a female fitting screwed into a 1 1/2" threaded fitting which is 'screwed' into the threaded fitting for my pool vac. At 40 psi, this connection doesn't leak. With the vac selected on the suction side of the pump and the cover off the pump basket I get an appropriate overflow of water, so there isn't enough of a line blockage to cause a priming issue.

I get the same results with the garden hose connected to either the spa drain or the skimmer.

With the pump set for normal operations I fill the selected input pipe with water via the adapter/garden hose. After the pump basket overflows for a while, I replace the basket cover and start the pump. Next I detach the adapter/garden hose and shut off that water supply. The pump sucks the water out of the filled input pipe and then continues with only a trickle of water into the basket...

Tom
 
Always fall back on this premise which is indisputable. If air is visible in the pump strainer basket, you have a suction side leak.

So that leak is coming from one of many, many places most always at some kind of joint or connection and often if you are using a vacuum hose. Especially if you are using spigot attachments most all of which leak.

How high above the pool water level is the pump?
 
Since you're having flow problems into the basket, I'd temporarily screw it into the drain port on the pump basket. It won't really matter where you install it in this case, as long as it's on the pump side of the issue.

However, as Dave mentioned. I'm not sure a gauge is going to tell you a whole lot that you don't already know.
 

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I will suggest using shaving cream to locate the leak. Lube the pump basket gasket, fill the pump with as much water as you can and tighten the lid. Slather up all suspected leak locations, including around the lid and the winterizing drain plugs on the pump impeller housing. Turn on the motor and see if the foam is sucked in any where.
http://www.poolrepair.com/archive/airleak.html
 
duraleigh said:
So that leak is coming from one of many, many places most always at some kind of joint or connection...Especially if you are using spigot attachments most all of which leak.
Click to expand...

Dave,

I don't have any spigots, but do they usually leak at the threaded attachment, the shut-off valve itself, or both?

Also, my pool vac (which during my testing has been detached from the fitting in the side of the pool) is a one-piece hose with a 1 1/2" threaded adapter screwed into the fitting in the side of the pool. I've pressure-tested it "on dry land" with water from the garden hose, and immersed with an air pump. No leaks at all.

Tom
 
duraleigh said:
It's hard to envision your seemingly complicated suction side
Click to expand...
Actually it only sounds complicated because of all the fittings and stuff I've added to keep air out of the suction side.

There are 2 J-valves that lead to the pump input. One selects either the skimmer or vac. The other selects the spa drain. That's it.

duraleigh said:
but, again, if there is air in your pump basket you have an air leak on the suction side.
Click to expand...
Agreed. I just can't figure out WHERE the air is getting in...

Tom
 
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