guidance with filter cleaning

anthony21078

Well-known member
Jun 14, 2018
76
Long Island NY
When we purchased our home last summer the pool was already up and running with no problems. After I learned to close the pool for the winter from this site, I put the pump, filter etc in the shed for storage after draining them. As I begin to prepare to open the pool, I figure I need to clean out the filter (Hayward DE3620) because I have no idea how old it is or when it was last cleaned. I'm going to follow the steps in this thread and it seems easy enough. DE Filter Cleaning Tutorial

Couple questions.
1)At what point should the grids be replaced? I don't how old they are but when I opened the filter, it doesn't seem to be terribly dirty.
2)There was a very very slow leak that would stain the lower body section of the filter that was coming from the center where the top and bottom meet. The o-ring doesnt looked damaged. Im not sure if the clamped was tightened to spec. Should I just replace the o-ring for good measure?
3)pressure gauge is broken. Will any gauge suffice?

Any other advice you can offer?
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Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,069
San Dimas, CA (LA County)
Grids get replaced when they rip. Or when they get so brittle that you're afraid they'll rip. Or when they get so calcified that you can't clean them. Sounds like none of those apply to you.

If you get a leak between upper and lower, replace that fat O-ring, and be sure to lube it real good. I like to stick a rag in my pocket so it's hanging out where I can grab it, then put a dab of pool lube every few inches all the way around the O-ring. Then start smearing it. When you're done, both hands will be a greasy mess, which is why the rag is right there to be grabbed and used.

Any gauge with the right threads can be used. Best is a low-pressure gauge, say 0-30 PSI. Then the graduations are bigger. Glycerin-filled is the Roll-Royce of gauges, and TFTestkits.net sells them. So if you need any test kit refills, get a gauge when you order them.
 
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anthony21078

Well-known member
Jun 14, 2018
76
Long Island NY
Grids get replaced when they rip. Or when they get so brittle that you're afraid they'll rip. Or when they get so calcified that you can't clean them. Sounds like none of those apply to you.

If you get a leak between upper and lower, replace that fat O-ring, and be sure to lube it real good. I like to stick a rag in my pocket so it's hanging out where I can grab it, then put a dab of pool lube every few inches all the way around the O-ring. Then start smearing it. When you're done, both hands will be a greasy mess, which is why the rag is right there to be grabbed and used.

Any gauge with the right threads can be used. Best is a low-pressure gauge, say 0-30 PSI. Then the graduations are bigger. Glycerin-filled is the Roll-Royce of gauges, and TFTestkits.net sells them. So if you need any test kit refills, get a gauge when you order them.
I purchased one of these gauges but the little note on the gauge has me a little confused. Once I open the plunger to release some pressure to "ensure accuracy", is this "OK" when used in applications that measure water pressure? Meaning, wont water come out flying out the gauge? Is that ok to have water flowing through the gauge?
9877498775
 

duraleigh

Admin
Mod Squad
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In The Industry
Apr 1, 2007
32,859
Sebring, Florida
Don't open the plug with the pump running!! It is there only to equalize atmospheric pressure inside the gauge and SELDOM needs to be uncapped.

The gauge is pretty accurate anyway but if the atmospheric pressure changes dramatically (as when a BIG cold front passes), you could see a small difference.

You didn't ask, but the glycerin level in your gauge is exactly right.....it is not supposed to be completely full.
 

Bama Rambler

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Jun 22, 2009
23,638
SouthWest Alabama
As Dave eluded to. That liquid you see in the gauge is glycerin. It's there to provide some dampening of the movement so the needle doesn't vibrate. The process fluid (fancy word for pool water) never sees that part of the gauge.

The reason for 'venting' the case is to equalize the pressure in the case to atmospheric conditions at the site of installation. For instance if the gauge was built in New Orleans and you were using it in Denver the pressure inside the case where it was sealed would be much greater than atmospheric pressure and would exert pressure on the bourdon tube and cause the gauge to read slightly incorrectly. And vis-versa.

Wish you hadn't asked, Huh??? :D
 

cfherrman

TFP Guide
May 10, 2017
2,384
Hays, Kansas
Might need to remove the guage and vent it straight up and down I can't remember exactly. Low range guages have this because the atmosphere pressure can make it 1-2 psi off.
 

anthony21078

Well-known member
Jun 14, 2018
76
Long Island NY
Great explanation. I got it....I did open the plunger slightly while side mounted after installed on a empty filter and tiny bit of liquid came out. I read that these types of gauges can be side mounted though.?


If not, I could exchange for a rear mount or but a 90° fitting
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,069
San Dimas, CA (LA County)
Great explanation. I got it....I did open the plunger slightly while side mounted after installed on a empty filter and tiny bit of liquid came out. I read that these types of gauges can be side mounted though.?


If not, I could exchange for a rear mount or but a 90° fitting
Go buy a "street elbow". Male threads on one end, female on the other, and it bends 90 degrees.
 

Bama Rambler

Mod Squad
TFP Expert
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Jun 22, 2009
23,638
SouthWest Alabama
Orientation doesn't affect the gauge, but my OCD requires that I buy a street elbow as Richard suggested so it will be oriented vertically. :)
 

anthony21078

Well-known member
Jun 14, 2018
76
Long Island NY
All good. Pressure after 4.5lbs of DE added.

Tank leak is gone. Lubed the seal real good and tightened the clamp to spec. Certainly helped to continuously smack the clamp with a mallet during the tightening. I noticed several times that once the nut was torqued to 150in lbs, a smack with the mallet would require a re-torquing multiple times
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