[Smudger]

So, I'm in a bit of a quandary regarding my 4040 RO system...

I've had my pure freedom system for about 7 years - in came with a van I brought and until now always been reliable - I know we produce a lot of pure between 1500 to 2000 most days but the last 3 membranes are only lasting 6 to 8 months before the TDS reaches 20+ at this point I have changed them as in the past as resin is £80 a bag and a bag only lasts 3 to 4 weeks.

Before putting in the latest membrane we cleaned everything with bleach and rinsed clean - we also put in a large carbon pre filter ( 12 Litre ) - all was good 004 this lasted 3 months - now the TDS is upto 12

 on the pure freedom setup the waste gate valve has a predrilled hole so when shut the system is pressurised and the correct amount of pure/waste is created - I checked the hole at the change of the last membrane and found the hole badly worn, I got a new gate valve and drilled a hole as per original - all ok

So, as the TDS has risen I thought (brainwave moment) that id I open the valve slightly -this reduced the pure rate to a trickle and got lots of waste HOWEVER the TDS went up to 30 

I have now tried the gate valve with a really small hole 1.5mm - the TDS is the same as the 3mm hole as per pure freedom but a much faster rate of pure

what I don't understand is why is the pure the TDS regardless of the hole in the waste valve and then higher if the waste valve is open  - ie on flush ? ( when the valve is fully open then no pure is produced

any ideas why this is


Cheers
Darran

[CleanClear]

on the pure freedom setup the waste gate valve has a predrilled hole so when shut the system is pressurised and the correct amount of pure/waste is created

I'm certain that Pure Freedom are much more experienced than me in these matters but that makes no sense at all (to me) . If everyones TDS going into the membrane is different, and everyones flow rate is different as is the pressure then how can a waste gate be "pre set"  ?

So, as the TDS has risen I thought (brainwave moment) that id I open the valve slightly -this reduced the pure rate to a trickle and got lots of waste HOWEVER the TDS went up to 30 

Water can flow through your membrane all the time. Its my understanding that under pressure and at the correct waste/flow  ratio then only pure water will escape through the membrane the rest as we know goes down the drain.

Analogy: Straining rice in a collander made for pasta. Shove a few grains in and they'll go right through. Drop a pan load in and they won't?

Summat like that anyway. You never mentioned your pre filters ?

[Smudger]

not sure it works like that - as far as im aware most set their pure/waste at 40/60 or 50/50 regardless of the setup
which is correct I do not know all I can say is for 6.5 years I was getting 004 pure from 300 to 350 tap water and lasting 18 months but then I was only producing 500 to 1000 litres

the simple case maybe that at near 2000 litres the membrane is clogged after 4 months

prefilter is sediment filter 20 inch and an 11 litre vessel of carbon changed every 12 weeks

Darran

[CleanClear]

I've noticed same as you membranes not lasting as long. I do think part of the case is that we are using more water. Also i reckon not many of us are using the membrane at its full efficientcy so that will also shorten its life. I think on Daqua website they cite :
To achieve maximum output on your 4040 Reverse Osmosis System the input pressure needs to be 80 psi / 5.52 bar and at least 21 litres/min coming from your water supply

We've started to change sediment filter every other week. To early to say if its going to make a diference yet, but they are quite discoloured when we chenge them.

[andyM]

Perhaps we are getting shafted from membrane manufacturers pushing lower quality membranes on to the market due to a higher demand?
Resin seems to be hit and miss at times too.
All I know is that the first 4040 membrane I bought lasted me 5 years.
I replaced it back in August 2018 and even though it's run at 100 psi with the same booster pump I have never been able to get this one (Axeon HF4) down to a TDS in single figures.
I think I was getting 12ppm when it was new and now 8-9 months later it's at 20ppm.     
I reckon I will be lucky to get 12 months out of this one before it will need replacing.
Utter crap if you ask me.

[Smudger]

Good points - mines also an axiom hf4 - boosted water pressure is 80 psi but no idea how many litres per min I doubt it’s 21 - perhaps I should plumb in my pressure washer that 21 litres a minute but I fear 3000 psi would be a tad to much 🤪
Darran

[Simon Trapani]

I'd speak to June at Gaps Water.

I'd also want to control my own pure/waste ratio with the gate valve, not the pre drilled hole Pure Freedom give in theirs.

[dd]

A water softener should prolong membrane life.

If you increase the waste water ratio I think it reduces the psi of the water going through the membrane.

Personally I think it best to have a ratio of about 40% pure/ 60% waste.

[windowswashed]

The more waste water , the less pure water produced, found the ro membrane lasted longer this way. The less waste water, the quicker the ro produces pure water but the ro membrane gets used up and needs replacing sooner.
I tend to set mine for 60 waste and 40 pure unless I'm short on water in which case I run it 50/50.
I swore by the carbon fibredyne blue filters as they kept my Axeon HF4 ro membranes lasting the longest, they were better than using anything else I've tried. 

[windowswashed]

I run my ro with the connection for pure water disconnected for the first couple of minutes whilst water is running through the waste water connection, then connect up my connection from ro membrane to pure water storage container so any higher tds water goes straight through the waste side

[Ooooooog]

Changing the ratio reduces pressure. Maybe that’s something to do with it?

[Small but perfectley formed]

Had same problem it's the axiom membrane they are excrement

[Bungle]

Good points - mines also an axiom hf4 - boosted water pressure is 80 psi but no idea how many litres per min I doubt it’s 21 - perhaps I should plumb in my pressure washer that 21 litres a minute but I fear 3000 psi would be a tad to much 🤪
Darran

Boosted and still only getting 80psi? I think you're using the wrong membrane. Have you thought about using an HF5 instead? Also test your water with another TDS meter to double check.

[Smudger]

Hmmm...

you got me thinking there,  perhaps somewhere over time ive got my 4 and 5 mixed up - ill have a look at the last invoice to see which I brought

Darran