i would love to set my rodi up in my crawl space and run a line up to where my tank is with a valve on it, however my crawlspace is usually about 50 degrees in the winter. i can't get rid of the nagging suspicion that i read somewhere once that 70ish degrees is the optimal temp for this process to take place.... and would it be merely less efficient at cooler temps, or would it actually be ineffective? anyone know?
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ro/di temp question
- Thread starter REEFLECTIONS
- Start date
Most membranes will operate more efficiently the warmer the water. Most will run well up to about 90F. You could tap both cold and hot water lines and mix but it will vary on you without a temp control. But it is possible. I do this and maintain about ~85F on my 75GPD RO/DI. I typically get about 80-85GPD from my system.
i work at a plumbing supply and can get a temp mixing valve for about $100.... i think i'll do this...
well, i can get a discount on the valve and other supplies need and can hook it up myself, so, why not....
to any interested parties, i have 3/8" sloan mixing valves, after you buy the fittings to adapt down to 1/4" for the ro would only be about $30
yea thats crazy i didnt know either i have straight up cold water in mine. Oh well guess it gonna have to do. but i have the adaptor that connects to my fauct will turning on both the cold and hot water at the same time due the trick instead of just the cold.
stcreef said:
I've never heard of this before. My RO/DI unit came with specific instructions for tapping into the COLD water line - NOT the hot water one. As a matter of fact I should never run hot water through there as per directions.
And that is correct Wendy, but you can increase the throughput with higher temp water. Up to about 90F. Most cold water lines run in the 45F-55F range. Most membranes are rated at a 65F temp. Lower temp, lower throughput because the water is denser. Raise the temp, it thins out and its easier to permeate the membrane. The DOW membranes will run at a much higher temp but 90F is about the average cutoff for most you will find in the states.
Here is a PDF.file from our sponsor Air Water Ice on how to set up/hook up a unit.
Please see page 3 on which line to tap into.
http://static.zoovy.com/merchant/theh2oguru/Reefkeeper_Installation_Guide.pdf
Please see page 3 on which line to tap into.
http://static.zoovy.com/merchant/theh2oguru/Reefkeeper_Installation_Guide.pdf
Here is a worksheet for the DOW membranes to calculate GPD based on your TDS, Feed Pressure and Feed Temp.
http://www.spectrapure.com/CALC-FORMULA.pdf
You'll notice in the temp correction chart the factor increases as the temp increases. The reason most hobby/consumer ro unit suppliers dont mention this is because it is typically out of the range of most consumers to be able to supply a correctly temp compensated supply. The reason being is that above 90F the membrane can start to basically dissolve depending on the manufacture. So its just simpler to connect to the cold water supply and be done with it. However, most lab environments, will supply a higher temp to the membrane to increase the throughput.
I will note that the feed pressure will have a better effect on throughput than will higher temps.
Don't always believe what the salesman says as gospel.
http://www.spectrapure.com/CALC-FORMULA.pdf
You'll notice in the temp correction chart the factor increases as the temp increases. The reason most hobby/consumer ro unit suppliers dont mention this is because it is typically out of the range of most consumers to be able to supply a correctly temp compensated supply. The reason being is that above 90F the membrane can start to basically dissolve depending on the manufacture. So its just simpler to connect to the cold water supply and be done with it. However, most lab environments, will supply a higher temp to the membrane to increase the throughput.
I will note that the feed pressure will have a better effect on throughput than will higher temps.
Don't always believe what the salesman says as gospel.
stcreef said:Don't always believe what the salesman says as gospel.
No? I was under the impression they knew it all. :
I'd like to play it safe, especially since I'm fairly certain that most of those who have their own RO/DI units don't have all the other toys needed to run their water at a specific temp with a specific pressure all the time.
And lastly, I would hate to void my guarantee by doing the opposite the manufacturer recommended.