Diy ro autoflush unit

[simonh]

Just to share with everyone a DIY autoflush for your RO unit. *I use my RO intermittently and so had a manual flush to keep the membrane nice and clean. *However, it was a hassle to remember to flush it very often. I had a search around and found the following autoflush unit HW AutoFlush unit (http://www.hw-wiegandt.de/Englisch/hw_Osmose_Technik/auto_flush.html) but it costs 200euros.

So, I decided to take a look for the parts myself. *I ended up on RS Components website and 1hr later picked up the parts from the trade counter:

439-082 Valve, solenoid, general purpose, 2 way, 1/8" BSP (439-111 for 1/4" BSP), 240Vac *EACH £23.88
440-852 Timer, DIN 43650 plug, multifunction, 110-230Vac *EACH £39.00

Assembly is simple and the timer allows you to setup the flush pattern and frequency. *I use a 30sec flush on startup and then every 60 minutes of use (this means with my setup it flushes every time it switches on and then a few times every day). *I put a T in the waste line from the RO membrane before the restrictor, then hookup the other output on the T to the solenoid (you will need some 1/4" or 1/8" connectors to fit the solenoid).

Here's an image of the finished thing:

http://www.wymag.org.uk/simon/dscn0499.jpg



Last edited by simonh at Jan. 17 2003,18:46

[wet weston]

Simon, I'm probably being really thick here, but how do I flush the unit? On mine there is no obvious connection or valve for this. I take it you have to disconnect the outlet and then flush water back through the unit? Just curious anything that improves the unit is a good idea to me!

[simonh]

I'll take a step back... A flush unit is used so that deposits don't build up on the membrane. Also, for a unit that is used intermittently it flushes out any bacteria that can also damage the membrane. A basic manual flush unit works by you switching a tap that directs water straight to the drain rather than it been forced through the membrane. Water is not backflushed but simply flows past the membrane and carries with it any deposits on the surface.

Kent do a manual flush kit for their RO units that consists of a tap, t-piece and a couple of other bits. You basically need to add a T before your restrictor on the RO, then put your restrictor on one of the outs from the T and a tap on the other. Switching the tap on then flows water straight to waste as it is not been restricted which forces it through the membrane. RO restrictors are sometimes inline on the front of the unit, or fitted into the elbow in the waste line of the membrane. If the latter then you need to carefully remove it and fit it inline with an adaptor (I actually replaced my restrictor with a needle valve that allowed me to adjust the good:waste ratio).

[wet weston]

Thanks Simon that explains it perfectly. My restrictor must be in the elbow of the waste union. Think I'll look into this and get one setup. Thanks again.

[simonh]

Be very careful when you remove the restrictor. *You will need a 1/8" (IIRC) female inline connector to screw it into and a new elbow to put in the membrane.

Here's a link to the Kent Manual flush kit which contains all the bits for a manual setup (for automatic just replace the tap with the solenoid) - http://www.kentmarine.com/fk.html they also have the instructions for fitting a flush kit here http://www.kentmarine.com/accessoriesin.html



Last edited by simonh at Jan. 17 2003,19:40

[tuan]

Simon,
I'm trying to assemble the parts for a few CO2 solenoids - got the solenoid from RS ok, but where do you get those air/water line connectors (1/4" BSP) from ? (the blue ones on your pics).
Cheers

[simonh]

My blue connectors are 1/8" thread IIRC. I'm not sure what they came off as they were in my spare bits box from old equipment. However, I found aquaristic.net seems to list a Knop part that looks similar: Here (http://store.aquaristic.net/AQ98b56cc18a107e031f5f2fddce110c8a/html_en/startshop.php?LANG=en&start=1&go=1&0.52525500+1043529694)

You may also want to try Jaco 1/8" or 1/4" connectors...

[reefer]

knop or schuran do those connectors as they are used on there equipment
watford have them..2 on a card

hth http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/eh.gif

[tuan]

Thanks Simon & Simon http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/smile.gif
Spoken to Danny already - he does have them. Just wished he would bring them sometimes http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/smile.gif

[philworrall]

I flush mine manually.
I simply remove the waste restrictor, turn on the tap for a few seconds and then push the pipe back in. The connectors only require you to push the little insert ring back and the pipe disconnects vey easily.


FREE FREE FREE no cost involved at all

HTH

Cheers
http://www.ultimatereef.com/ibv3/iB_html/non-cgi/emoticons/biggrin.gif