[alanwilson]

What's the port for then? Why is the flush check valve plumbed into it?

Before you say I'm making anything up check you're right first, you think GE just stuck a port on there for the fun of it?

http://www.freshwatersystems.com/p-3604-ge-merlin-flush-kit.aspx

Have a look at the direction of travel of permeate water coming from the flush kit, it goes through the membranes the reverse way and then out the drain, the check valve allows this.

[www.com]

First of all the Merlin is designed as an under the sink ro for drinking water. That means it is on and off sporadically when the tap (faucet) is turned on. The issues with any ro's is they need a few litres of water going through them before they kick in, the initial burst of water out of the unit has very high TDS which kills the resin in some window cleaners set up.

The flush tank simply holds some purified water and mixes it with the initial high TDS when you turn it on, this helps reduce the TDS 'spike' mentioned on the flush tank description.

The Merlin is designed as a minimal fuss domestic unit for the average home owner. This is why there is no back flush to confuse things.

[alanwilson]

No it doesn't! Have you got a merlin? Prob no!

Look at the flipping diagram and stop spouting, have a look on gapswater site for more clarification.

Honestly you are giving poor, ill-informed advice.

[www.com]

Yes and had a flush tank.

What has Gaps water got to do with it? READ THE MANUAL!!!

No where in the literature does it say to do what you suggest yet i'm giving poor, ill-informed advice? Please. 

[alanwilson]

It's all there for you to see, seriously, that's what it is there for!

It's to reduce salt diffusion across the membranes, improves life of the membranes.

The damage or wear as such, to a membrane, is mostly caused by when it is at rest, the salts settle in the membrane via osmosis because the membranes are not under pressure. It's usually known as salt diffusion and the prob it causes is fouling, or scaling of the membrane, which reduces surface area and therefore the membranes become less efficient, slowing production rate etc.

You can get the larger diagram at GE's web page (need to google it)

[www.com]

OK not to argue over this but here is the manual:-

http://www.freshwatersystems.com/specifications/MerlinInstallManual.pdf

I cannot see where something as big as this could be missing? Where have you got your info from??

Also read the link you provided carefully. The flush tank is for TDS creep, not for cleaning membranes.

[alanwilson]

TSS creep - that is another name for salt diffusion!

[alanwilson]

Ok I had a look at your link

Please see pages 7,8 and 12 to start with.

Your own link talks about a flush tank numerous times.

[Lee GLS]

I think I have to agree with Alan, if you read this it clearly says that it flushes the outer membrane to reduce the salt saturation with pure water, this is done automatically after each use.

I can see what mrindustry is saying because it basically it's to prevent tds spiking when it hasn't been used for a while.

[www.com]

Read what it says on the last paragraph of the flush tank info:-

'The flush kit is recommended for applications where a spike of TDS at system start-up is not desirable'

Its not for unclogging membranes. Nowhere does it say to rig up a pump and blast it through the flush port to prolong membrane life. This wont work with the Merlin as it does with other RO systems.

[alanwilson]

You can't unclog a membrane without chemicals, we know that. Flushing only helps lessen the impact of diffusion.

The point about Tds spike is relevant as the kit flushes high Tds water away from the membrane with permeate (low Tds/after ro) water.

As regards connecting a pump to flush the merkin, we do it (shurflo 5.2ltr/min) pump. Have a merlin at my sons for about 5 years now, still going well, 2500 ltrs approx a week.

Have a twin 4040 at mine

[www.com]

Would be interesting to run an experiment side by side with leaving a Merlin as is and doing what you guys do. 5 years is a very long time on one set of membranes.

[Cliff perkins]

You can't unclog a membrane without chemicals, we know that. Flushing only helps lessen the impact of diffusion.

The point about Tds spike is relevant as the kit flushes high Tds water away from the membrane with permeate (low Tds/after ro) water.

As regards connecting a pump to flush the merkin, we do it (shurflo 5.2ltr/min) pump. Have a merlin at my sons for about 5 years now, still going well, 2500 ltrs approx a week.
How exactly do you flush it and do you run a booster on it and what tds do you get out of them and whats your tds before you go through it.
Please
Have a twin 4040 at mine

[www.com]

Thats an interesting point. When using the booster pump, what is the TDS of the water going in? and the water coming out of the waste?

That would be a test to see what rigging up the flush valve does.

[alanwilson]

Here goes.

We use a shurflo window cleaning pump to flush the membranes, it's a spare pump with a 1/4 inch push fit attached. Other end is plugged into merlin flush port, pure water gets pumped in. Obviously tap water into merlin is switched off at time.

We flush it for about half an hour.

Tap Tds in is around 110, Tds out normally 7 or 8.

Tap pressure when running is about 70psi.

Pure water flow is around 75ltrs an hour, obviously not as efficient as new membranes but still doing well enough.