RO membrane flashing for the first time

Evening All, just connected new 4040 system. Now I need to open valve fully and flush for 20 minutes. Do I disconect DI vessel when flushing or flush whole system?

moto said:

Evening All, just connected new 4040 system. Now I need to open valve fully and flush for 20 minutes. Do I disconect DI vessel when flushing or flush whole system?

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The membrane needs a really good flush longer than 20minutes if it’s brand new. It is wise to disconnect the DI before flushing, just wait before you begin, to get some better info. @spruce or @doug atkinson are your men for a good answer. It’s worth the wait they will help you. This bit is so important. You want the best out of your membrane. 

I have never disconnected the DI vessel in 9 years of flushing membranes. Only a tiny trickle of water will go through the DI during flushing

Thanks Jango! System is from @doug atkinson , instructuctions say 20 minutes flush, then adjust the gate valve slightly. But you are right, will leave it till I speak to Doug and double check next steps... thanks

I have replied to your message

Part Timer said:

I have never disconnected the DI vessel in 9 years of flushing membranes. Only a tiny trickle of water will go through the DI during flushing

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Ok that’s interesting. I was told to by pure freedom, but if it’s worked ok for you, you have more experience than me. ?

Jango said:

Ok that’s interesting. I was told to by pure freedom, but if it’s worked ok for you, you have more experience than me. ?

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My system is a van mounted system supplied by PF, my second one. They never told me to do anything but open the waste valve. Might be different for wall mounted, but I can't see why.

Part Timer said:

My system is a van mounted system supplied by PF, my second one. They never told me to do anything but open the waste valve. Might be different for wall mounted, but I can't see why.

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I don’t know confusing. I’m not at the new membrane stage as yet I’m hoping for a couple more years out of it yet. Who knows though???

Jango said:

Ok that’s interesting. I was told to by pure freedom, but if it’s worked ok for you, you have more experience than me. ?

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Same as @Part Timer I also have a Pure Freedom system and I was never told to disconnect my DI when flushing. I never have in 2.5 years of having it.

Thanks, I dont think its an issue just dont want to filter through DI and use resins whilst testing.

It’s more about volume of water than time when flushing. Also, if your pressure is super good, you will still get a bit of flow of pure and will be wasting resin. 

moto said:

Thanks, I dont think its an issue just dont want to filter through DI and use resins whilst testing.

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When flushing no water is going through the resin it’s all waist or at least  99:9% of it will be going to waist , so it won’t be affecting the resin life 

Thanks Guys. What are my next steps?

Should I flush again for 10 minutes, then close waste valve slightly, run 5 minutes and check TDS? Or, adjust to 60waste / 40pure and run 5-10min then check tds? What's the easiest way to mesure 60/40? All that without DI to see if RO is doing its job? Thanks

tap tds - 350ppm

tap pressure 40psi

Should I get under 20ppm after RO?

moto said:

Thanks Guys. What are my next steps?

Should I flush again for 10 minutes, then close waste valve slightly, run 5 minutes and check TDS? Or, adjust to 60waste / 40pure and run 5-10min then check tds? What's the easiest way to mesure 60/40? All that without DI to see if RO is doing its job? Thanks

tap tds - 350ppm

tap pressure 40psi

Should I get under 20ppm after RO?

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With a new membrane and filters I would hope, once bedded in, to get it out at less then 10ppm. 98% of 350 is 7ppm, 96% is 14ppm

This system has already been flushed and tested. At 30 psi rejection rate was 97% then at 45 PSI 98 %.

i have advised just flush for 15 mins or so then set to around 60 % waste. You don’t have to measure it to get it exact but as long as the waste is more than pure it is okay. If pure is more than waste it brings the ppm up and damages the membrane.

When you first set the ratio the first 5/10 mins the pure water reading is always high then gradually settles.

Always take  a ppm reading after about 15 mins as this gives a better reflection. If you have measured water before this rinse the cap you are dipping the TDS meter in as the solids from the previous reading will still be there.

Hope this explains it a bit more as per instructions.

Thanks Doug, wanted to double check all again ?

Sorted. I have 0ppm water ?

30psi

22ppm after RO (waste/pure ratio set as per pictures, with slightly more waste water)

0ppm after DI

2 litres per minute

Sounds OK?

Another question; suspended the delivery pump (https://www.machinemart.co.uk/p/cse400a-11-2in-submersible-water-pump/?da=1&TC=GS-051010690&gclid=EAIaIQobChMI45rChLi-6QIVEu7tCh1vHQZLEAQYASABEgLCxvD_BwE ) slightly above botton of the tank, should I drop it all the way down? Thanks