[Walter Pole]

I've just put new membranes into an old merlin system and ran it for about 2 hours. The tds is way too high still at 68 to 71. Any ideas why this would be?

I thoroughly cleaned all the housings beforehand....

[Smudger]

What is your tap tds and water pressure, sometimes you need to run new membranes for a while, but without knowing tds in and pressure  I can't say whether that's acceptable or not

Darran

[Walter Pole]

268 tds in
Don't know what water pressure is here although I did have to buy a pump for my 200 gpd system as pressure wasn't enough to get below 20 tds at the time.

So is it possible to buy a pump for the merlin?

[Smudger]

Yes but buy a decent one, loads on here use a Clark pump from machine mart

Darran

[Walter Pole]

Thank you Darran.

I'll check auntie Google now for price and delivery.

[Matt.]

Try different tap for water until u sort your booster pump out, this will be the problem.

[Walter Pole]

Regarding the clarke pump...now I've done some research..is the pressure cutoff adjustable? Just that some others are and I wonder if it will cut out from the carbon block first membrane..

[Spruce]

My solution would be to put the money towards a better r/o such as a 4021 or a 4040. If your water pressure is low then use HF5 membranes.

[Smudger]

While you say the 4040 is a better system (which it is) the Merlin is much maligned, if set up well with a good booster pump you can get well over 100 lph and tds below 15 from tap water in the high 200's - had mine for over 3 years producing a good 2k of pure every week and only changed the membranes once.

they are a great intermediate RO  system , easy to use, easy to maintain

Darran

[Walter Pole]

Thanks Spruce but I'm kind a committed to what I have...just spent 168 pound on membranes and want to make it work.

I have a school contract to do next week that will use 1000l a day or more to get done and my current system only provides about 400l a day.

[Walter Pole]

Before I buy a clarke booster pump I would really like to know if the pressure switch is adjustable as others are and I'm concerned it will not work with the merlin basic 20 inch system I have....anybody?

[Smudger]

I use this ( j102)
http://www.anglianpumping.com/products/dab-jet-mp-230v-pumps

I think you would only need a pressure switch if you have a float valve or auto shut off

HTH

darran

[Walter Pole]

Thank you again Darran
I would like a pressure switch because I have 2 ibc 1000 litre containers joined in tandem with a ball clock valve to stop over filling.

So ideally I want a pump that has a solenoid cutoff when the water is full it stops the pump and water supply.

I'm in need of a booster pump that makes the merlin ro system work as it should due to low water pressure where I am but isn't too sensitive to the pressure of the system itself.

Reading other posts...actually only one..The standard pressure switch may  be set too low to recognise a merlin ro system. If it's adjustable then that's great but if not I may have to go with an Italian made pump.

Any help much appreciated and thank you for comments so far.

[Smudger]

They do these pumps with a pressure switch but ive always timed my fill ups before it overflows 

If you ring Anglian pumps they would be able to advise the exact pump and pressure switch combo required

Darran

[8weekly]

While you say the 4040 is a better system (which it is) the Merlin is much maligned, if set up well with a good booster pump you can get well over 100 lph and tds below 15 from tap water in the high 200's - had mine for over 3 years producing a good 2k of pure every week and only changed the membranes once.

they are a great intermediate RO  system , easy to use, easy to maintain

Darran

I've just replaced my membranes and with a Clarke pump get 12 out. 270 in.

[8weekly]

Without a pump though, that's still a very high TDS output from your input.

[Smudger]

I think that it is high but without a pressure reading from the mains it's not possible to know  my water pressure is around 15 psi resulting in 50 from the Merlin.

I would also invest in extra per filters carbon and sediment, the Merlin prefilter is too small and would require changing every couple of weeks


Darran

[Walter Pole]

Ok so 8 weekly the clarke pump works fine from what you're saying.

On the other point you raised ro membranes are only supposed to be good to 90 percent...so 15 us good from over 200

[8weekly]

Ok so 8 weekly the clarke pump works fine from what you're saying.

On the other point you raised ro membranes are only supposed to be good to 90 percent...so 15 us good from over 200

Yes, but before I changed my membranes it was 38 output. The point I'm making is that the combination of new membranes and a good pump gives a good output. Does your Merlin have a gauge to measure pressure?

[Walter Pole]

No but I can probably cobble one up from an old ro system. The water pressure is definitely low when I live. A fellow window cleaner in the same town has similar issues.

From what I've learnt today the clarke booster pump will solve my problems...its just a case of getting one in time!