Circulation problems

[garmtn]

Hi, I have a real dillema w/vacuum line presure. I have a 20k gal pool; hayword pool vac, and 10, 3' sections of vac hose. When properly working, the line pressure is about 10lbs. Put brand new sand in filter, 250lbs, and backwashed. Still getting less than 5lbs of pressure on line? However, when I left robot hooked up and backwashed, line pressure shot up to 10lbs and robot took off. What gives? Any ideas?

My skimmer /main drain may b clogged also. My filter is running high @ 52lbs and my vacuum line isn't above 3lbs?

[I've merged 2 related threads and 2 posts within those threads, for simplicity and clarity. PoolDoc ]

[PoolDoc]

Not really clear on the piping arrangement you are describing, nor the location of the pressure gage in the piping. You might want to send some pictures to poolforum.pics AT gmail DOT com. I'll post them, and then we can move forward.

Ben

[PoolDoc]

Here are the pictures:

1.


2.

[PoolDoc]

In your email, you mentioned eliminating your unions. If I were you, I might replace them with unions that had a more positive connection, but they are not your flow restriction.

I see two likely culprits.

The Hayward chlorinator will restrict ALL flow -- if you remove it, look though it. The hole that ALL your pool water has to flow through is about 1" in diameter. That's the likely cause of your 52# filter pressure. I used to throw those things away, any time I found them on a pool with a pump larger than 1/2HP.

I'm going to be take some pics at my wholesalers. I'll see if I can get a picture of the interior of that mis-designed piece of pool gear.

Second, if the green corroded ball valve is on your vacuum line, we may have found the guilty party. Such valves often have a small port. If that valve is on your skimmer line, it will mean that water always finds it easier to flow through the main drain than the skimmer. In that case, you'd have very poor suction pressure. (Are you using a pressure side, or a suction side cleaner?)

Ben

[garmtn]

Suction side cleaner. Also, I plan on replacing those valves with "lifetime" plastic valves I picked up. Thanks for info and will reply after I replace plumbing and check chlorinator.

[PoolDoc]

Not sure what "lifetime" plastic valves are, but I have a couple of suggestions:

#1 When you remove those brass ball valves (worth about $10 scrap, right now!) make your new connection with a male/female threaded pair. That way, if you have to work on the lines in the future, you simply unscrew the part above ground. You can use RTV silicone as a thread sealant, if you like. Or, since they are suction lines, you can use Teflon tape, and the if you have a bit of a suction leak, you can use silicone to fix them -- the suction will pull the silicone into the threads and stop the leak permanently.

#2 Make SURE your valves are full port valves - that is that the opening in the valves is as large or close to it, as the opening in your pipe. Looks like you have 1.5" ID pipe, so you are looking for valves with a 1.5" port.

Ben