Booster Pump / How to run 12V on 230V

[spruce]

I would buy the whole package from Gardners now and put the water saving toward the repayment. Then sell the merlin on Ebay.

In my case I would still purchase a single sediment filter housing to put before that, again purely because of the amount of sediment in our water. But with most this won't be neccessary.

I'm not sure why we are so prone to this as others in ajoining towns on the same water supply don't seem to complain about having the problem.

 

[heyoh]

Hi Spruce,

Finally got around to do this experiment.

Basically i conected the tap to my shurflo pump in the van, and checked the difference when it was turned on and when it wasnt.

The pump only gave an extra 10-15 psi, which was a surprise i expected 100 as thats what is on the label..

Anyway, i used a 0.33l bottle, which without the pump filled in 68 seconds, with the pump about 40. So yes the pump made production quicker. Then i checked the waste water, without the pump the bottle filled in ~6 seconds, with the pump ~4 seconds. Now that seems to confirm what you stated that the amount of watrer used will not change, i still did the math

Without pump for 100l pure you get 1131l waste

With pump for 100l its a 1000l waste.

I think my calculations are correct, although this production rate looks terrible either way... I need a new ro../emoticons/sad.png

 

[spruce]

Hi Heyoh,

Thanks for doing the experiment and coming back to us with the results.

I knew Merlins to be heavy water wasters but I didn't realise that pure to waste ratio is that great, 10 to 1; wow.

On top of that you will have a efficiency of around 90% (TDS in to TDS out) so you will be throwing money away on resin as well.

I think you may find that the pump isn't giving you that much of a pressure increase because so much water is going to waste. I would expect that the r/o is consuming around the maximum delivery of the Shurflo pump and that it why you aren't getting much of a pressure rise. Your pumped figures indicate that. If you had a 7 LPM pump you would record a pressure rise of a little more.

The other issue of concern to me would be the amount of chlorine removal the Merlin carbon block filter has to deal with. Our 4040 is set at around 55 waste to 45 pure. I have done a prefilter change 3 weeks ago. Since then we have already processed just on 20,000 litres of water to get around 9000 litres of pure - and we haven't worked for a week of this period due to bad weather.

Had this been your Merlin then we would have used approx 100,000 litres of water to get the 9000 litres of pure we have used since the filter change.

A new 20" fiberdyne from Gardiners has a chlorine removal service life of around 75700 liters. The 10" is around 38,000 litres.

If I were changing carbon block filters to the letter of instruction, I would be half way through my 2nd 20" fiberdyne filter at £24.00 + VAT.

We know chlorine destroys membranes over time, so we are left with a conundrum. Will our chlorine removal filters last longer than the manufacturers suggest? The reason why I ask is Merlin users aren't having to replace their membranes every few months - if they did we would all know about it. Or, does chlorine do the amount of damage to membranes that we are led to believe it does?