0 PSI on filter

[jesse-99]

So I've been wondering...

I have a (2) Pentair CC100 filters I use that are specifically tied to a dedicated water feature pump. I run the pump on low RPM usually (1400-1750RPM), so my filter pressure is usually 0-1 PSI. Will the filter still be filtering well enough without any pressure or would I be better off closing the valve (post-filter) a bit to create more backpressure within the filter?

Same thing for my mobile-vac-cart (I have a hand-truck with a Pentair CC75 and a VSP pump -- see pic), whenever I use that, the filter pressure is usually 0-1 PSI as well. Will the filter still be filtering well enough without any pressure, or would I be better off closing the valve (post-filter) a bit to create more backpressure within the filter?

Obviously I rather not run the pumps at a much higher RPM just to create pressure, if it's not needed, and the filter will be fine filtering around 0-1 PSI. I guess I'm just trying to think about filter efficiency and what is ideal/better based on low/some/med/high pressure on the gauge. (I've read that filters are more efficient when the pump is at a lower RPM, so that's why I've assumed, thus far, that a 0-1 PSI reading is perfectly fine when I run my pumps at low RPM).

 

[Jimrahbe]

Jesse,

Filters work off of water flow, not "back-pressure".. The filter PSI is backwards from what many think.. The lower the better... The gauge really measures how 'hard' it is to force water through the filter.. The higher the pressure, the harder it is to push water through the filter, and the lower the flow.

Thanks,

Jim R.

 

[jesse-99]

@Jimrahbe I guess I started to ask myself this because when I use my new mobile cart (pic above), I literally never get water coming out of the top air-relief valve when I open it. It lead me to believe that water is never getting to the top of the filter, and maybe water isn't even getting halfway up the the filter? Maybe the water is only 1/4 of the way up, which in turn means only the bottom 25% of the filter is even being used... That's why I wondered if it might be better to close that valve more on the output side of the filter, to increase the PSI, and hopefully increase the overall filter area being used, and be able to get water to come out the relief valve so I know the entire filter is submerged. Does what I'm asking making sense?

Maybe the entire filter media is under water regardless of whether I get water out of the air relief valve or not. I don't know? I wish the filter housing was glass so i could see inside .

 

[Jimrahbe]

@jesse-99

There are just no dumb questions...

I have a CCP-520 filter and even at 1200 RPM, water will shoot out of the air vent, if I open it.

I have no idea why it does not come out of your much smaller filter.. But... You bring up a good point.. My system has to move the water through the filter and then SWCG and then a valve and then through the plumbing and back into the pool.. Of course the pool is full of water, which causes some back pressure. I guess that all kind of acts the same as a partially closed valve on the output of your filter would..

Why not just crank up the speed a little and see what happens..??

Thanks,

Jim R.

 

[jesse-99]

I can get water to come out of the air bleeder it seems from a) partially closing the valve on the output side of my filter (even at 1750rpm), or b) running a higher RPM (like 3250). It seems that since running a 0 PSI pressure on the filter is perfectly okay, then I probably shouldn't worry about it much. I can probably do either A or B as mentioned above if I was to verify water is filling up the entire filter cartridge.

I'd be curious if, when I take the filter out for the first time, only the lower half of the filter is dirty at all, lol.

Thanks for the insight. So far I really love this mobile cart. The plan is to use it in late Fall and early Winter, after the pool is already closed, to help keep water circulating and have a blue (closed) pool all winter long instead of looking at a cruddy pool for months on end. I did it last year (through I borrowed my pool service guys mobile cart last year since I didn't have my own) and it worked out really well.