Fleck 7000SXT Carbon Filter - Extremely Loud Backwash & Rinse

[schmeckp]

I recently installed a whole house carbon filter, which consists of a 13x54 tank, 2.5 cu ft of GAC and a Fleck 7000SXT head. Everything appears to be functioning correctly except I'm surprised by the noise produced when running through the backwash and rapid rinse cycles. Because of the volume of carbon, it is setup to backwash at 10GPM (and does fill a 5 gal bucket in about 29 seconds). The drain line is 3/4" PVC. The backwash and rapid rinse cycles are both setup at 10 minutes each, on a 7 day cycle.

From what I can tell, the noise seems to be cavitation around the DLFC washer, which may be standard at this high of a flow rate, but louder than I was expecting. I found advice on clearwatersystems.com that recommended running a backwash, moving to bypass, pulling out the button, moving the system back in service for a few minutes to flush the drain of air, and then putting the button back in. I tried this, but as soon as the system is put back in bypass, the drain line empties and is filled with air again.

My house water pressure is 52psi, and the main line is 1"CPVC leading into and out of the whole house carbon filter. After the filter I have a water softener with a Clack WS1 head that is substantially quieter (but of course at a lower flow rate).

Has anyone else experienced such a loud backflush / any ideas to quiet it?

[ditttohead]

The drain adapter is 1" and the pipe should not be reduced. Youe DLFC is correct at 10 GPM. The high velocity through this button will cause noise.

Confirm the DLFC button is installed the correct direction, the numbers should face down.

How often are you backwashing? How long?

In a residential application, every other week is fine, 10 minutes BW, 5 minutes RR is a common setting. You can also change the time it backwashed to the middle of the day so the noise doesnt wake you.

[schmeckp]

Thanks for the quick reply. The button does face numbers down. BW is 10 min, RR is also 10 min. Currently setup to flush every 7 days. Perhaps I'll extend that to 10 days or so. I have someone home most of the time during the day, so would prefer to keep the flushing to nighttime - just wanted to validate I wasn't crazy and the noise was common due to the flow rate.

[ditttohead]

Thanks for the quick reply. The button does face numbers down. BW is 10 min, RR is also 10 min. Currently setup to flush every 7 days. Perhaps I'll extend that to 10 days or so. I have someone home most of the time during the day, so would prefer to keep the flushing to nighttime - just wanted to validate I wasn't crazy and the noise was common due to the flow rate.

Nah, your not crazy. The DLFC on most systems can be very noisy due to the high velocity that goes through the flow restrictor. The restrictor will throttle down the port size at higher pressures, changing, and usually increasing the noise. Lower pressures usually have less noise, but the flow remains the same. As you saw by your test, the flow is very accurate.

[Gilley7997]

Confirm the DLFC button is installed the correct direction, the numbers should face down.

Can someone clarify 'face down' as in should I be able to read the numbers on the button while it is still installed in the 90 Degree Elbow?

[ditttohead]

The simplest way is to make sure the numbers face the valve. Water should flow through the numbers. On the 7000 DLFC you should be able to read the number when it is installed in the 90 degree drain elbow.

[Gilley7997]

Thanks for the clarification.