Fleck 6700XTR cycles seem incorrect

[cgarai]

My 6700 doesn't seem to be going through the cycles correctly. I just ran it through its cycles by manually starting a regeneration, the purpose being to measure the BLFC flow rate. I have it Regenerant Flow set to Down Flow Double Back Wash, which has 5 cycles:

Down Flow Double Backwash:

1. Back Wash
2. Brine & Slow Rinse
3. Back Wash
4. Rapid Rinse
5. Brine Tank Fill

When it got to Cycle 4 it started flowing out the Brine Line
When it got to Cycle 5 it started flowing out the Drain Line, stopping the Brine Line flow.

This is a 6700XTR so it has an LCD that displays the cycle it is in. This is not my understanding of what is supposed to happen!!

I will try setting it to other Regenerant Flow modes and see if the seem to match the expected states. In the mean time, any ideas?

The manual is here : http://www.pentairwatertreatment.com...ow%2042132.pdf

Thanks,
Chris

[ditttohead]

First off, is your 6700XTR a single or double backwash valve? The valve is basically the same, the micro-switch cam would be different for single or double backwash. It is pretty easy to determine. Program the valve for single backwash, if the cycles match, then you have a single backwash valve. Same goes for the double backwash, program it to DBW, if the cycles match the programming you are good to go. One of them will not match.

It sounds like you have a single backwash valve.

1: BW
2: BR
3: FR
4: BF

[cgarai]

That is probably what is going on. I am not at the site at the moment, but will let you know. I didn't know that the valve is one or the other.

Thanks,

Chris

[cgarai]

So that was the issue. Looking carefully at the parts diagram I now see that there is a double backwash version of the cam. I'm not sure I understand why that would be necessary with a digital controller. It seems to me that the controller would be able to position the valve as needed for single or double backwash.

What does double backwash provide? Is it worth changing over to?

Thanks,

Chris

[ditttohead]

So that was the issue. Looking carefully at the parts diagram I now see that there is a double backwash version of the cam. I'm not sure I understand why that would be necessary with a digital controller. It seems to me that the controller would be able to position the valve as needed for single or double backwash.

What does double backwash provide? Is it worth changing over to?

Thanks,

Chris

Double backwash is advantageous for ultra low salting, downflow brine applications. It is a simple way to eliminate the majority of the problems associated with ultra low salting. If you use 6 pounds or more per cu. ft. then it is not necessary. Even at 4 pounds per cu. ft., most people cant tell the difference.

The newer valves use optical sensors to determine where they are, the older valves, like the 5600SXT, 6700XTR, 2510 SXT, etc use physical micro switches. The double backwash cam has an extra spot in it for the micro-switches to position the valve in the second backwash position.

In my own testing, in a normal household application, it is difficult to tell the difference. Even with hardness ppm testers, (not GPG) unless the system is being run to the point of having virtually no reserve, it would be hard to notice any change between the two. When a system is pushed on flow and capacity, the double backwash does show a testable difference in water quality, ie: lower hardness bleed, but most people would not notice the difference.