ditttohead
Water systems designer, R&D
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Resin in backwash?
- Thread starter Kamisn
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Update! I installed the new basket, internals and sized down the DLFC to 2.2, sanitized the brine tank and softener and measured backwash to a 5 gal bucket and it measures at 2:45 minutes which per above formula is 300/165= 1.8 gpm at the end of the drain line.
I have no resin in the bucket anymore
, however I am wondering if the 1.8 gpm at the the drain line for backwash is OK number to get my Vortech tank to raise the resin bed and wash it properly?
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Bannerman
Well-Known Member
What is the length and diameter of the drain line? How does this drain rate compare if measured nearby to the control valve?
If the nearby measurement is 2.2 GPM, then look for a restriction in the drain line extension or if no restriction present, you may need to increase the diameter of the extension.
If the nearby measurement is 2.2 GPM, then look for a restriction in the drain line extension or if no restriction present, you may need to increase the diameter of the extension.
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The drain line is 1/2” 75 ft long. We went from 2.7 to 2.2 per suggestion from this forum to avoid resin loss during backwash , if you look at few posts before with 2.7 DLFC, I had around 2.2 - 2.5.
I have to cut the drain line to get the close by gpm.
Bannerman
Well-Known Member
Often, the softener's installation manual will specify to increase the drain line diameter when the length is to exceed 15'. While 1/2" tubing can easily flow 2.2 GPM, a long drain length will increase flow resistance. While a small reduction to the flow rate is not usually critical for most water transfer applications, a specific flow rate is required for media backwash so any restriction can negatively impact the results unless compensation is performed.
The usual recommended backwash rate for softening resin is 4-5 GPM per ft2 to acheive 40%-50% bed expansion. For a 10" diameter tank, this calculates as 2.2 - 2.7 GPM but because you are using a Vortech tank, the DLFC rate will need to be reduced by 15-20% as Ditttohead stated in post #9. These flow rates are based on a backwash water temperature being 60 - 69F. If the water temperature is 50-59F, then the flow rate will need to be further reduced by 10% whereas if the water temp is 70-79F, the DLFC rate will need to be 10% higher.
The usual recommended backwash rate for softening resin is 4-5 GPM per ft2 to acheive 40%-50% bed expansion. For a 10" diameter tank, this calculates as 2.2 - 2.7 GPM but because you are using a Vortech tank, the DLFC rate will need to be reduced by 15-20% as Ditttohead stated in post #9. These flow rates are based on a backwash water temperature being 60 - 69F. If the water temperature is 50-59F, then the flow rate will need to be further reduced by 10% whereas if the water temp is 70-79F, the DLFC rate will need to be 10% higher.
So does this mean I am not getting enough GPM drain with current drain line setup to backwash properly? Should I put the 2.7 back in? I guess the right way to do it is to keep the 2.2 DLFC in and change the drain line to 3/4 but that will be a major project with bunch of yard digging and pulling a new PVC pipe all the way.
ditttohead
Water systems designer, R&D
You should be fine as it is. Leave the 2.2 in. Did you check the resin level?
I have 2/3 of the tank full of resin.
doesn't matter which way you do it. you're just looking for a specific flow at the end of the backwash line.
ditttohead
Water systems designer, R&D
Perfect, all should be fine. Perfect backwashing of resin is less critical than most people will admit. If you consider the earliest automatic regenerating valves only had an upflow brine/slow rinse cycle, no backwash, no rapid rinse, no timed refill... these systems actually lasted very well under reasonable water conditions.
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