Pentair IC-40 Insuffient Flow Indicator Light Problem

[hodapmj]

I have an IC-40 SWG with a Intelliflo 4x160. Normal operating RPM is 1700, which gives me a turn or so a day on my 24,000 g pool. A recent anomaly has popped up. My low flow indicator light is coming on the IC-40, in turn stopping any clorine production. The only way to get the low flow light to go back to normal is to manually increase the RPM. When I increase the RPM, it resolves the issue for maybe a few hours to a day, but the low flow light will always come on.

I removed the IC-40, and it is free from obstructions, in fact after a year of use, it is still looking like new inside. I have backwashed the filter, and it may work fine for 24-48 hrs and then go back to low flow, even though the PSI change has only gone from 8psi to 10psi. I have been running the pool for a year at this 1700rpm without issue until the past two weeks.

Does anyone have any suggestions or experience with this type of issue?

 

[Strannik]

First thing to try is cleaning the cell.

 

[hodapmj]

Cell is sparkling clean with zero obstruction. No build-up, all plates are shiny and clean.

 

[JasonLion]

Have you cleaned out the pump strainer basket recently? Blockage there could cause the symptoms you are seeing.

 

[hodapmj]

Have you cleaned out the pump strainer basket recently? Blockage there could cause the symptoms you are seeing.

Pump strainer basket is cleaned everytime I backwash and is currently clear. I use skimmer socks and have even tried removing those to see if the flow is actually impeaded. My hypothesis is that with a clean SWG, clean skimmer & filter baskets, it must be the flow sensor that is giving the bad reading. Pentair does not quote a minimum flow in GPH for when that sensor should come on, but I would think my pump running at 1700rpm should give me enough flow. My three eyballs and spillway do not seem to have any change in their output.

 

[Strannik]

I don't understand something. You are saying that when you increase the rpm it starts working fine, and then stops again. If this is the case, you would be at maximum pump rpm after continuously increasing them. Or do you increase it, and then bring it back down?

 

[hodapmj]

I don't understand something. You are saying that when you increase the rpm it starts working fine, and then stops again. If this is the case, you would be at maximum pump rpm after continuously increasing them. Or do you increase it, and then bring it back down?

What I am saying that by increasing the RPM, I am increasing the flow. For example, I start at 1700rpm, I have good flow. After about 24hrs the NO FLOW indicator on the SWG comes on. I then increase my pump speed to 2000rpm, and the indicator will go back to green (good flow). However, it may be another 24-48hrs and the NO FLOW indicator will come on again. This time I may have to increase RPM to 2400 to get the indicator to turn off. If I do try bring the RPM back down I will get the NO FLOW indicator.

Of course if I kept this up, I could get to maximum RPM. What seems to "clear" the issue is by backwashing the filter which is usually within 48hrs and no increase in PSI with the exception as I increase RPM I increase the PSI naturally. Based on my Intelliflow Pump curve, I should be getting about 35gpm at 1700rpm. I would think that would be more than sufficient flow. Plus, it has been running @ 1700rpm for about 1 year without this issue.

 

[sredish]

maybe the cell is just bad, despite no buildup.

 

[Strannik]

What I am saying that by increasing the RPM, I am increasing the flow. For example, I start at 1700rpm, I have good flow. After about 24hrs the NO FLOW indicator on the SWG comes on. I then increase my pump speed to 2000rpm, and the indicator will go back to green (good flow). However, it may be another 24-48hrs and the NO FLOW indicator will come on again. This time I may have to increase RPM to 2400 to get the indicator to turn off. If I do try bring the RPM back down I will get the NO FLOW indicator.

But does it work properly when left at 2400rpm? Or it shows the light after some time?

 

[hodapmj]

What I am saying that by increasing the RPM, I am increasing the flow. For example, I start at 1700rpm, I have good flow. After about 24hrs the NO FLOW indicator on the SWG comes on. I then increase my pump speed to 2000rpm, and the indicator will go back to green (good flow). However, it may be another 24-48hrs and the NO FLOW indicator will come on again. This time I may have to increase RPM to 2400 to get the indicator to turn off. If I do try bring the RPM back down I will get the NO FLOW indicator.

But does it work properly when left at 2400rpm? Or it shows the light after some time?

It will eventually in 24-48hrs also reach a NO FLOW indication after 2400rpm, therfore requiring an increase in RPM to resolve the error light.

 

[mas985]

Sounds like you simply do not have enough flow for the sensor. 2 PSI may not seem like much but it is about 5' of head loss and at 1700 RPM, this could easily move the flow rate down such that the switch turns off.

For example, if you normally have an 8 PSI filter pressure at 1700 RPM and 35 GPM, increasing the filter pressure to 10 PSI would drop the flow down to 10 GPM! So it is no surprise that flow light would come on then go off after a backflush.

I am not exactly sure about where the flow rate triggers but I believe it is around 20 GPM which again would explain what you are seeing.

 

[Strannik]

Can you try and find a point where you won't need to raise rpm to keep it going? Just interested what that point will be (if any). It seems unusual that it behaves like that.

Did you speak to Pentair's technical department? Did they give you any suggestions?
You could always try and replace flow switch module, but that would be waste of 200 bucks if that's not the problem.