Jandy Cart filter

[gregg123]

My pool is 5 months old, I have a Jandy CL340 cart filter. There is a gauge on the top for the pressure. It also indicates clean and dirty arrows. When the pool was new the PB set the clean to about 9psi and the dirty arrow is at about 20 psi. The pool has always run at the 9psi when the pumps are on but jumps to about 21psi when I turn the vales to the spa. Never any problems.

Like I said, its been 5 months and I expected the psi arrow to reach the dirty mark indicating time to clean the filters. Never moved off of 9psi still in the clean area. Well, I have noticed a lot of dirt on the bottom after the pumps stop, so I took apart the filter for the first time to clean them. All 4 were coated with sand and mud, totally filthy. Cleaned them all and they looked new, nice and white. Put everything back together and still, the psi was 9 and when I switch to the spa it goes up to 21 psi.

The questions is, why did the psi gauge never go up as the filters got dirty? And, why does the psi go up so high when I switch the vales to the spa?

 

[waste]

The gauge should have risen off of 9 in the course of 5 months :? The only thing I can think of is the water somehow bypassing the filter grids as they clog (but you still should have seen some rise in the gauge). It's perfectly normal for the pressure to rise when you go to spa only mode (you are running the same pump on a more restricted system), 12 psi sounds a little high, but if it's been working fine, 21 psi isn't going to harm the system.

Even though the gauge didn't leave 9, how was the return action, this is a good indicator of a dirty or clogged filter, as the filter accumulates debris, the returns get weaker. I originally suspected a bad gauge, but it jumps to 21 when the spa is on so the needle isn't stuck (does it go to 0 when the system is off?)

I'm at a loss as to why the gauge didn't 'inch up' as the filter did it's job - perhaps someone else has a suggestion. Please keep me (us) informed if you find out what the cause was

 

[gregg123]

I suspected the filters were getting dirty because the returns had lost some pressure. Yes, the gauge goes back to zero when the pumps are off.

Anyway, I guess I will just make a point to clean the filters monthly.
Thanks!

 

[frustratedpoolmom]

I know all filters/carts are different, I have don't have a Jandy but my filter/cart gauge doesn't budge when dirty either. As a rule we tend to hose it off every 6-8 weeks. I know when my filter is dirty if the heater won't kick in, it's pressure switch is pretty sensitive.

 

[TexasTwister]

In my experience, few PSI gauges accurately indicate "clean" or "dirty". Most of my clients' filter gauges don't budge off a certain PSI, even if the filter is very dirty (my own Pentair filter gauge included). This is particularly frustrating when clients, thanks to their PBs, believe that the gauge accurately reflects the cleanliness of their filter and you are in the business of cleaning filters!

The best thing you can do is develop a cleaning schedule for your own filter, with timeframes based on what you see when you crack that baby open during certain times of the year. Over time, you will fine tune the schedule base on your observations and variations in pool usage.

 

[crabboy]

I have the CL340 as well and the pressure always hangs around 10psi. I've had the pool about a year and a few months and have cleaned the filter twice. My PB told me to clean the filters once a year in the spring after the pollen has settled down. I did just that the first time and then a second time after a river of mud was washed into the pool (long story). Anyhow, I think once a month is probably more effort than required.

 

[duraleigh]

As a filter collects dirt, the resistance to the flow of water increases and the result is an increase in psi.......that's pretty inescapable.

If your system is not performing like that:

1. Your guage is innaccurate

2. The flow is somehow being allowed to "bypass" the increased resistance in your filter

3. You really don't have any dirt in your pool.

There may be some other possibilities that don't come to my mind right now but my point is that if your filter psi does not increase thru the collection of dirt, something is wrong and should be corrected.

And, why does the psi go up so high when I switch the vales to the spa?

Because your water is now required to take a different path that has much more resistance (primarily, the smaller return jets) to flow. Increased resistance to flow equals increased pressure.

 

[gregg123]

The pressure gauge seems to be functioning. Goes to zero when off and rises with the pumps. My pumps and equip are very close to the pool. Maybe 8 feet. Maybe the pressure is so good with the pumps that close that some dirt in the filters just doesnt make it rise enough to make the gauge go up?

 

[waste]

Where in the system is the feed for the booster pump installed? (If it's between the pump and filter, that may be where the pressure is going -- I'm not sure I like this hypothesis, but it's all that comes to mind for now :x )

If the gauge won't tell you when the carts need cleaning, you are best off cleaning them on a ~ regular basis (Waterbear wrote an excellent description of the method here)

The carts will be easier to fully clean and last longer if you clean them before they are fully congested! It only takes a short time to clean them and then you KNOW that all is good :-D

Once you have a little more experience with your pool, you'll just know when to do the routine maintenance it may need.

 

[gregg123]

That cleaning method was very informative. Will try that next time. He also said having a monster filter may cause the pressure readings not to increase that much when they are dirty. That may be the problem we are having. I have 4 big Rear filters in that canister. Even clogged up they may be large enough to keep the water flowing and pressure down.

 

[launboy]

As a filter collects dirt, the resistance to the flow of water increases and the result is an increase in psi.......that's pretty inescapable.

That's what Science says, but in the real world that's often not the case. I'm speaking from Sand filters here but I think it still applies.

My pump pushes about 30 GPM with solar on and noticably more with it off, maybe like 40GPM? but I never measured with it off.

Anyway, starting pressure with solar off and on is 9/11 respectively. This is a 1HP pump and 100lb sand filter... My guage is functioning because I replaced it this spring, it goes to 0 when off, to 3 on recirc., and increases when I start to restric flow via valves.

As time passes(usually 2 weeks to a month) the gauge hardly moves, MAYBE 1 PSI if I'm lucky, but the flow is noticably diminished. I only have 1 suction, 1 return and nothing between pump and filter. I backwash based on flow and the water is always very dirty. The flow always returns full force after the backwash. This may not be the case in all situations, but if my flow is becoming less and less the water is not just bypassing the sand, but for some reason, the PSI doesn't go up. I can't explain it, it defies all logic, but I just know it happens.

Adam

 

[mas985]

While it is true that a filter will collect dirt over time and as the dirt builds up, the pressure in the filter will also rise, the amount of pressure rise also has a lot to do with the filter size. The larger the filter, the less the pressure rise will be for a given period of time. Given a large enough filter and a reasonable cleaning frequency, you may not see much of a pressure rise at all.

I too have a cartridge filter and I hardly see a pressure rise at all over a 6 month period. I clean my filters every 6 months and they are quite dirty when I do. To me, this is a good indication that the filter is sized properly. Undersized filters require more frequent cleaning and experience higher pressure rise than an oversized filter. Also, undersized filters do not clean as well as oversized filters.

To often, PBs undersize cartridge filters so the pool owner is having to clean them once a month or even more. I know that I don't want to clean my filter more than twice a year so I am very thankful that I went with an oversized filter. BTW, I could easily get a way with cleaning them once a year but simply choose to do it more often.

So bottom line is that with a properly sized cartridge filter, you should not see much of a PSI rise between cleanings. I would extend that to other types of filters as well but since it is easier to backwash, it is probably not as important as it is for a cartridge filter.