[Brownie10]

Hi

Installing it does not seem to be a problem, but in the manual it has a diagram with a carbon postifilter connected- whats this? Do I need it? How much are they?

Also if someone would kindly explain whether I need to then attach a di vessel to polish the "last bit" of water, as I think I am in a hard water area, my tds meter reads 310ppm...

I am aware that I may be confused with where the di vessel goes, but It would be great, Ian from Window washers if you could advise too as you know all the equipment I have.

Thanks

[clean]

you defo need to add a di vessel,you need to add it to the pipe that produces the product water,so as the water is being filtered from the merlin its going straight into di vessel then into your tank, 

[Brownie10]

Thanks for your help. What do you think about the carbon post filter, do I need that before setting it up.

[clean]

Don`t bother with the carbon filter,i hav`nt and my merlin is over 4years old and it`s still reading same tds as from day 1 

[Brownie10]

Ok cheers pal, will let you know how I get on, as no doubt I will come across another hurdle soon

[MopTop]

Carbon postfilter is supposed to remove chlorine I think. It's not essential for w/c water (only if you're drinking the product water).

I have used a merlin to prefilter my water for about 4 years now.  I recently moved from a soft to a hard water area (275 ppm from mains).  I saw the PPM of my output water increase from less than 10 to around 110.  This meant my polishing DI resin was only lasting 6-8 weeks, as opposed to 6 months in the soft water area.  If your 'raw' tap water is as high as you say (300+ ppm) you will encounter this problem, also, the lifespan of the expensive membranes in the merlin will be greatly reduced. 

My suggestion is to add a small resin bottle containing water softening resin to the feed line between the mains and the merlin unit, this will dramatically reduce the input TDS.  I did this and managed to get my input TDS down to 140, giving product water around 60ppm TDS.  Softener resin is much cheaper to replace than DI resin, so over the long term you'll save money.
Hope this helps

[Brownie10]

 Very clever suggestion moptop and thanks for the advice.

Just to clarify then, I would still need to buy mixed bed resin for the di vessel, however at a much lower rate because I will already be reducing my ppm before going through the merlin with soft resin, meaning less work to do from my system in the first place.

You say..

"...managed to get my input TDS down to 140, giving product water around 60ppm TDS"

Is this "produc water" then what you put through your merlin, or you seeing it as ready to use because I thought you needed  010 to 000ppm for wfp?

I would definately like to try this method, where did you get your resin bottle from?

Thanks

[MopTop]

No worries. To clarify:

Yes, you will still need a mixed bed DI vessel between your storage tank and the van.

Input water is water from mains that enters the merlin unit, either directly or via a vessel containing softener. By reducing the hardness of this input water you are making life easier for the RO membranes in the merlin.

Product water is the filtered water that comes out of the merlin. (you also get 'waste' water which goes into the drain or a garden water butt). 

The product water from your merlin in unlikely to be purified enough to use on windows as is, hence the need for the polishing vessel to reduce PPM to 0. So when I say i managed to reduced my product water TDS to around 60 PPM, this means my DI resin doesn't have to work as hard to finish the purification, making the DI resin last much longer.

I got the vessel to house the softener resin as a complete unit (inc. riser and manifold) from the cleaningspot website. IMO they offer brilliant value and free delivery on orders over £50.

One more tip (sorry for long essay): if you ever get an interrupted mains supply (e.g. brown tap water) try to avoid using your merlin during said interruption.  We had brown tap water for only 2 hors a couple of months back and the brown sediment trashed both membranes and the carbon prefilter!

All the best
Paul

[Brownie10]

Top stuff Paul, I will defo get one of those