[david wood]

i am just about to buy a new ro unit ive heard a lot of great things about the merlin is there any downsides i should no before i order one thank you

[H h20]

Hi Dave,i use the merlin ,nice and affordable for how much water i can produce,although i have got good water pressure iv`e been told merlins need a booster pump to get the tds down,my tap reading is 315 and after merlin 27,im not too bothered though im still on my first bag of resin almost 12 months and still oo reading,  ,Gaz

[top rung]

i use a merlin have done for 9 months.tap water in at 425 arter ro 8 not using pump and resi still ok.

[Andrew McCann]

Unless you have good water pressure (60 psi plus) the merlin isn,t very efficient.

It's a good piece of kit if set up under the right conditions. Low water pressure and its not so good at all. IE low TDS reduction and high waste to product rato. It's also a good idea to add a 20 inch carbon prefilter to protect the membranes from chlorine whatever pressure you have.

You can get a booster pump is needed.

Hope this helps

Cheers

Andrew

[twt]

ive got a merlin use the 60 psi pump on my trolley to boost pressure 285 in 000 out 2:1 waste:pure fill up 250 litres in about 2 hours

[david wood]

thanks lads yes my water presure is very low here and very hard but we are moveing house very soon if i needed a booster pump do i have to plug it into the electrics as i may want my ro to be mobile and fill up where ever possible

[squeaky-clean 1]

hi guys

where am i going wrong i have merlin tap tds 350-375 after ro 35-40 high tap presure and my resin last just 8 wks we use approx 500ltrs a day.
and i think my waste i 5-1 pure
and with water shortages i want to go on to water meter.

Belinda

[top rung]

As i said earlier mine goes in at 425 and comes out at around 6,7,8, before di.I only use at present about 1000 ltrs aweek and have done fore about 8 mnths and my resin is still fine in the di .BUT my water goes through a water softener first so as when i bought the merlin they said it would work much better .Maybe the softener makes quite a lot of difference ?.

[twt]

look in manual, i think the max pressure you can put in is 80 psi the closer you get to this the better it will perform.

[JM123]

Hi squeky-clean1 chances are your sediment/carbon block is done - change it and if poss buy a softener vessel and 5micron prefilter, will set you back about another £150 all in but definitely worth it.  Also have you backwashed the membranes lately?? This needs to be done every 3 to 6 months but as your tap tds levels are high I'd recommend doing this every 3 months.  What size of resin vessel are you using??

[twt]

hi JM123 do you have a merlin? i dont think you can back wash the merlin i thought back washin was for the softners.

[twt]

also dont buy a booster pump just use the pump you already have for you wfp to boost the pressure going in to the merlin.

[twt]

see this link for improving merlin performance http://www.cleanitup.co.uk/smf/index.php?topic=15127.0

[Filllllll]

I'm pleased with the merlin.

430 going in,  15 coming out on water pressure of 65.

wastage ratio 2.75:1

gives me 1 litre per43 seconds.

Want to improve wastage ratio and cut down on meter cost?

Put a manual control valve on the waste hose, the more you close it up the less waste you get.
 Down side is the purity goes down.

on a waste ratio of 1:1  tds shows around 45 and also fills the tank a bit quicker.

Have yet to figure if this is more ecomomical long term considering  resin costs etc.

[JM123]

Hi Phillip Thomas, we stock the merlin and it comes with all systems we build.  The top John Guest fitting on the merlin is for backwashing, the kit is a pressurised vessel which forces permeate back over the membranes.  The booster pump for the merlin was developed by Aquatec specifically for the merlin, the reason for this is that the merlin operates most efficiently at 70psi where most wfp pumps are closer to 90/100psi.  Also with a waste to product ratio of 3:1 where product is 2.3lpm this results in a gross input of 9.2 lpm which none of the wfp pumps can supply.  Yes you can fit a manual valve to increase output but this again results in poorer product water, decreased membrane and filter life expectancy and increased resin use.  By using the purpose built booster pump you will increase output, membrane and filter life expectancy, improve product water tds levels and use less resin, also as a final note using a manual valve is fine as long as you don't close the valve over as the merlin was designed as a positive pressure unit (ie - continual flow).  Speak to Arthur @ surecleansystems.com if you want a booster pump.

[twt]

correct me if im wrong but i thought the flush tank prevents the high tds you get when you intially start the merlin up. This is benefitial when the merlin is started and stopped frequently such as in drinking water situations so no tank is required to hold the permeate  and the tap wouldn't have to be run for a few minutes to get pure water. The manual doesn't say that the merlin needs flushing the only maintance is the changing of the filters isn't it. Also i have found that a consistant tds of 000 and 2 parts waste to 1 part pure can be achieved by using a 60 psi pump without restricting the waste outlet as some have suggested, with pumps with a greater psi capacity the varistream can be used to set the pump to the correct pressure. surely it makes more sense to do this rather than spend another £100+ on another pump?