fahz
11/11/2005, 09:27 PM
What’s wrong with my RO/DI water system?
We hear that question a lot and the answer is generally nothing. The problem has more to do with operating conditions rather then something is wrong with your water system.
You bought your new RO/DI water system with a 100GPD membrane and you ready for water making. After the first day you notice your production is nowhere near what you expect. In fact your production is so low you think something must be blocked, chances are if you take your system apart you’ll find nothing wrong.
Here’s the deal RO membranes are made to produce the stated GPD at a water temp of 77 degrees the colder your tap water the lower the production. How much is a surprise, with tap water at 55 degrees your 100 GPD production is reduced to 62 GPD but that’s not the whole story.
TEMPERATURE CORRECTION FACTOR
• FEED WATER CORRECTION FEED WATER CORRECTION
• TEMPERATURE FACTOR TEMPERATURE FACTOR
• ºC ºF ºC ºF
•
•5 41.0 2.58 18 64.4 1.29
•6 42.8 2.38 19 66.2 1.24
•7 44.6 2.22 20 68.0 1.19
•8 46.4 2.11 21 69.8 1.15
•9 48.2 2.00 22 71.6 1.11
•10 50.0 1.89 23 73.4 1.09
•11 51.8 1.78 24 75.2 1.04
•12 53.6 1.68 25 77.0 1.00
•13 55.4 1.61 26 78.8 0.97
•14 57.2 1.54 27 80.6 0.94
•15 59.0 1.47 28 82.4 0.91
•16 60.8 1.39 29 84.2 0.88
•17 62.6 1.34 30 86.0 0.85
Divide the rated permeate flow at 77 degrees Fahrenheit by the temperature correction factor. The result is the permeate flow at the desired temperature.
Factors number two and three are your house water pressure PSI and TDS in the water. Here’s how to figure out what you can expect based on your current PSI and TDS.
100 GPD corrected to 55.4 degrees water temp (100 GPD divided by 1.61=62 )
Home water pressure at flow PSI (PSI minus 10)
TDS of raw tap water (TDS minus 20)
EXAMPLE
Using a PSI of 60 and a TDS reading of 100
( 62 GPD ) X (60 minus 10) PSI divided by TDS of (100 minus 20) =38.75 gallons per day.
We hear that question a lot and the answer is generally nothing. The problem has more to do with operating conditions rather then something is wrong with your water system.
You bought your new RO/DI water system with a 100GPD membrane and you ready for water making. After the first day you notice your production is nowhere near what you expect. In fact your production is so low you think something must be blocked, chances are if you take your system apart you’ll find nothing wrong.
Here’s the deal RO membranes are made to produce the stated GPD at a water temp of 77 degrees the colder your tap water the lower the production. How much is a surprise, with tap water at 55 degrees your 100 GPD production is reduced to 62 GPD but that’s not the whole story.
TEMPERATURE CORRECTION FACTOR
• FEED WATER CORRECTION FEED WATER CORRECTION
• TEMPERATURE FACTOR TEMPERATURE FACTOR
• ºC ºF ºC ºF
•
•5 41.0 2.58 18 64.4 1.29
•6 42.8 2.38 19 66.2 1.24
•7 44.6 2.22 20 68.0 1.19
•8 46.4 2.11 21 69.8 1.15
•9 48.2 2.00 22 71.6 1.11
•10 50.0 1.89 23 73.4 1.09
•11 51.8 1.78 24 75.2 1.04
•12 53.6 1.68 25 77.0 1.00
•13 55.4 1.61 26 78.8 0.97
•14 57.2 1.54 27 80.6 0.94
•15 59.0 1.47 28 82.4 0.91
•16 60.8 1.39 29 84.2 0.88
•17 62.6 1.34 30 86.0 0.85
Divide the rated permeate flow at 77 degrees Fahrenheit by the temperature correction factor. The result is the permeate flow at the desired temperature.
Factors number two and three are your house water pressure PSI and TDS in the water. Here’s how to figure out what you can expect based on your current PSI and TDS.
100 GPD corrected to 55.4 degrees water temp (100 GPD divided by 1.61=62 )
Home water pressure at flow PSI (PSI minus 10)
TDS of raw tap water (TDS minus 20)
EXAMPLE
Using a PSI of 60 and a TDS reading of 100
( 62 GPD ) X (60 minus 10) PSI divided by TDS of (100 minus 20) =38.75 gallons per day.