[[GQC] Tim]

Just wondering which supplier sells a electronic timer for 12v solenoid control. Should be programmable for mid fill flushing etc.

Seen some 12v programmable timers on ebay, maybe some suppliers use the same tech?

[[GQC] Tim]

No one?

[Spruce]

Hi Tim
I've been looking for something like this myself.

I'm sure it is Ian Lancaster who has one fitted to his 4040. I'm sure he has a 230v standard timer (not digital and the one we use to program a small light to come on at a certain time when we are away or during the winter) which is connected to his auto fill system. He would then use a 230v solenoid valve normally off. Once the timer clicks on every 24 hours r/o useage it opens the solenoid valve to waste.

Problem I see with this is that the smallest activation time is 15 minutes, so his r/o gets a 15 minute flush every 24 hours.

If you have your r/o on your van, 230v is not an option without creating endless hassels.

I'm afraid my understanding of electronics is much to be desired but what about something like this?

http://www.ebay.co.uk/itm/DC-12V-Power-ON-Delay-Timer-Time-Relay-1-999-Seconds-/160573850376?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item2562f28308

This is 12 powered so the way I see it is that the 230v section could also be 12v which would be fine for a solenoid valve. Once you plug your system in then the way I see it is that you could set the delay to from 1 to 999 sec (16 minutes) and it will flush before filtering at every start up. Probably need a normally open solenoid valve for this. (I hope I'm not talking rubbish!) 

[Ian Lancaster]

Hi,

I do have a 240 timer section on my RO with a standard 240v progammable timer without the 24 hr 'repeat' that most of them have.

This is purely for the 'flush' function - the start/stop operates via a tank side mounted 12v float switch which activates two 240v relays, one to open the mains water solenoid valve and the other to switch on the booster pump.

The problem with 'normally open' solenoids is that in the event of a power failure, or solenoid failure the mains water would all run direct  to waste - it could be several hours (or even days) before you noticed and the system would keep on running because the storage tank wouldn't be filling up.

Regarding the 15 minute flush - I have the timer wired into the power feed to the pump, so it only advances while the pump is running, ensuring the flush cycle is per 24 hrs of actual running time.  This has been very successful with the last HF4 membrane lasting well over 3 years and still producing at less than 10ppm from about 300ppm input.  For the minimal cost of a 15 minute flush every 24 hours, I'm quite happy with that!

[Ian Sheppard]

HI I may be missing something here. As I understand it you are looking to control an RO flushing and control solenoid valves. You are also looking to be able to accurately time this process.

Is this the type of thing you are looking for?
http://www.springltd.co/node/123

[Spruce]

HI I may be missing something here. As I understand it you are looking to control an RO flushing and control solenoid valves. You are also looking to be able to accurately time this process.

Is this the type of thing you are looking for?
http://www.springltd.co/node/123

Hi Ian

I looked at this earlier and was going to ask you about it.

I have a 230v solenoid valve normally off operated by a float level switch is the tank which is the same as a submersible pump uses but wired the other way. I'm looking for an automatic preset flush arrangement that can be setup and forgotten about - which is what I'm getting good at lately - forgetting.

I'm afraid the r/o membranes on my RoMan type r/o weren't flushed as regularily as they should have been. When I did flush, after the r/o had kicked in, I usually forgot to switch the flush off after 5 minutes or so, a fact usually noticed by the wife who remarked about how much water was coming out of the discharge/waste pipe.
So with my new 4040 I was looking for an automatic flush system that would operate regularily and without my intervention.

I read Ian Lancaster's post a while ago which I found interesting. He said that his flush system was on a old style 24 hour timer (motor driven) that was operated only when the r/o was in use. Again this would be easy for me to set up using another 230v solenoid valve. So setup gave Ian a 15 minute flush every 24 hours of filtering as this is the minimum time that these timers can be setup for.

I like that idea but feel the 15 minute flush is rather long for me - our water Tds is around 115ppm to his 300.

Thanks for your input.

Spruce

[Smart Carpet]

According to June at GAPS You would be better off flushing for 1-2 minutes every hour or so. 

[Spruce]

According to June at GAPS You would be better off flushing for 1-2 minutes every hour or so. 

June is very knowledgeable and I respect her advice.

Ian's membranes have lasted 3 years so his approach it not all wrong. My previous membranes lasted 6 years even with irregular flushing. Are we making much more of this than we need to? I’m just asking the question.

A fellow window cleaner has a Merlin and his never gets flushed. The last membranes were in there 4 years before needing replacement, but got damaged with frost rather than failure because of not flushing.

Ian uses much more water than I do, so does that mean that if we had the same water tds, his would need replacing before mine?

Personally, I think there are too many variables to have a definitive answer.

[Ian Sheppard]

Hi Spruce

The mains controller + timer was developed for dosing applications or to run a pump for a specified period and preset delay.

It is in effect a pump controller with the usual protection with an added timer.
The unit is powered using 240V AC using a transformer output is 12V DC maximum current rating on output is 12 amps

Dosing/Pump run time can be programmed between 6 seconds an 99.9 minutes. Each increment of 0.1 increases time by 6 seconds.

Dwell time between pump runs can be programmed between 6 minutes and 99.9 hours and each increment is 6 minutes.

We can add solenoid and float switch input/outputs these would be 12V DC relays. In the event of power failure or problem with the pump the control shuts down the pump. In theory you could use the 12V relays to activate a 230V solenoid as Ian does.

There is also liquid logic S2 which is a different bit of kit all together but aimed at RO control.

[Sure Cleaning]

We have this fitted to our ro system:

http://www.ro-man.com/shop/index.php?route=product/product&path=23&product_id=225

Flushes for 18 seconds every hour.


Steve