[Chris - CBWC]

I need some help understanding my RO and if I'm using it correctly.  For those of us with van mounted systems who fill up daily from an outdoor tap - do you flush the RO on 100% waste for a certain amount of time before gradually closing the waste tap to start filling the tank?  If so, how long for?

I ask because it seems, no matter how long I flush on 100% waste, when I start to close the tap, what comes back out of the RO starts at about 150ppm (tap is 250ppm roughly), then gradually goes down to around 20, which is obviously then fine to go into the DI (my system goes tap > pre-filters > ro > di > tank so water into tank is 0ppm).  Trouble is I'm sitting there letting it dribble into a jug, get a TDS reading, if too high then chuck it out the door, take another reading.  It does go down eventually, probably minutes rather than half an hour, but I'd prefer not to have to sit in my van every day doing this if there's a much simpler way.

At the moment I obviously can't just turn on outdoor tap, close the waste tap a bit and leave it to fill up as it would wreck my resin but it's a real pain having to do all this while thinking there must be a simpler, better way.

[Colin h]

Can't you mark where the perfect place is on the waste?
Then turn it to there when you have flushed?

[Chris - CBWC]

I know roughly where it is, but there's nowhere to actually mark, it's a case of me knowing roughly what the flow into the tank sounds like, and the flow out of the waste.  But I don't know how long to flush for, or if flushing even makes any difference as what comes out of the waste is generally the same ppm as the tap.  It's only when it goes back through the ro and into the di that it starts to come down, but the ppm doesn't immediately drop down to what it should be, I have to keep testing it.

[Colin h]

I only flush once a week,I would look into a booster pump
It should bring the tds straight down,then mark your waste
With a pen or some tape

[PoleKing]

Use a gate valve to find the sweet spot.
Once you've found it. Don't touch it.

RO waste, 1 hose. Split that. When filling, run the water through the gate valve, when flushing, let the water take the other (uninhibited route)

If you text me I'll show you how mine is with a photo.
Can't post pic on here (using iphone)

[Chris - CBWC]

So is this magical sweet spot where the water that comes back through the ro is immediately at the right ppm to go through the di?  If so, then does that mean I'm closing my waste tap too much, meaning the ro can't clean the water effectively and that's why it takes several minutes for the TDS reading to come down so the water is usable?  Hope not as it means I'm knackering my membrane very quickly and if I have to open up the waste tap more, the slow trickle into the tank becomes an even slower trickle 

[PoleKing]

So is this magical sweet spot where the water that comes back through the ro is immediately at the right ppm to go through the di?  If so, then does that mean I'm closing my waste tap too much, meaning the ro can't clean the water effectively and that's why it takes several minutes for the TDS reading to come down so the water is usable?  Hope not as it means I'm knackering my membrane very quickly and if I have to open up the waste tap more, the slow trickle into the tank becomes an even slower trickle 

The Ro should bring your TDS down to about 90-95% of inlet TDS.
Any less then you may have a problem with either your set up or your RO.
I have known of membranes not working properly but they are few & far between.
As for the trickle, that'll be all down to your water pressure.
Might you need a booster pump?
Where are you? Perhaps someone local could have a butchers...?

[Chris - CBWC]

I'm in Knaphill in Surrey, if there is someone nearby that can help I'd be happy to drive over.

Someone has recommended a booster pump, about £300 I think and then I'd have to get someone to fit it.  The cold water mains seems to be ok, kitchen and bathroom tap wise, but the hot water pressure is bad.

The ro does bring the TDS right down to around 19-20, just not immediately, I always thought it should do that straight away.  Can't tell you what type of 4040 it is without unscrewing it all, which I'm really not that keen on doing, but if it's needed...

[PoleKing]

You need a pressure meter bud.
You can't tell by looking.
You're a bit far from me or id've come over. sorry.

Fitting a booster pump is easy. inlet>pump>outlet jobdone.
£300 seems expensive though.

Ring these guys http://www.dualpumps.co.uk they are pretty good at over the phone diagnosis and will probably explain clearer than I.

[Colin h]

I can't stress how much a booster pump helps,I had a trickle
Going into my tank for years,booster pump from Purefreedom
It's flooding it to the tank