Slow R/O unit water production

[mike31154]

Originally Posted by Coralgurl

Hmm, not sure that's the reason, I was running the unit yesterday and it was quite nice. I've never found temps to be an issue, only with evaporation.

Colder water will definitely have an impact on production. Membranes are designed to produce their rated output at a certain water pressure/temperature. I'll take a guess & those numbers are probably around 21 degrees C temperature & 60 psi water pressure. Any deviation from those numbers will cause a deviation from rated production. I stuck one of those strip thermometers on the housing of my 1st stage sediment filter and during the winter months the incoming water gets down to 8 degrees C. Highest incoming water temps I see are August through September when it gets up to a whopping 15 degrees C. That's still 6 degrees below the temperature at which my 75 gpd membrane would actually produce 75 gpd. Colder water means colder membrane which in turn means the tiny pores in the membrane will be smaller & more water will bypass instead of being pushed through the thin film. A day or two of mild weather will generally have little impact on the huge reservoirs most of our water suppliers use. My water comes out of Kalamalka lake, so it takes a long time for temperatures to change during the different seasons.

The positive side of colder water I've found is that I can get 0 TDS out of the membrane within 10 minutes of start up, saving on DI media. In the summer I never get 0 TDS from the membrane, best I can do is 1 TDS..... but production is faster....