Heating intake water for RODI

[Sleepingtiger]

Here in Dallas, the water gets quite cold during the winter. I know that water temp has a huge effect output. I tried to run 100' worth of tubing through a cooler filled with water and a heater. It worked good until the heater came in contact with the tube, melted it and had a huge water leak in my house. I also hate the look of a cooler sitting on my counter.

Anyways, I was thinking of a inline heater.


Is this a bad idea?

For all those who live in the north, what do you use?

Im not trying to increase my output, just trying to decrease my waste water. More waste water means faster replacement of carbon blocks. The carbon blocks for chloramine isn't cheap.

 

[Mike konesky]

I have an electric inline Bosch water heater that I use when needing RODI fast in winter. It's been carefully set to have an output of 75-77. You will double your output AND your tds when going from 55 to 77. A heated hose will not do the trick in case you are curious.

 

[KStatefan]

I do not heat my water. I wish it was cold all year since there is a better rejection rate with cold water. Water temperature here has ranged here from 55° F to 75° F.

 

[Sleepingtiger]

I have an electric inline Bosch water heater that I use when needing RODI fast in winter. It's been carefully set to have an output of 75-77. You will double your output AND your tds when going from 55 to 77. A heated hose will not do the trick in case you are curious.

Can you sharer he model number of that Bosch heater?

 

[Sleepingtiger]

I do not heat my water. I wish it was cold all year since there is a better rejection rate with cold water. Water temperature here has ranged here from 55° F to 75° F.

Wait? You like the water cold because you have a better rejection rate? That doesn’t make any sense. Everywhere I read is that when the temperature of the input water drops below 70f, waste water increases and your output decreases.

 

[Mike konesky]

Can you sharer he model number of that Bosch heater?

bosch es 4-1m wir

 

[KStatefan]

Wait? You like the water cold because you have a better rejection rate? That doesn’t make any sense. Everywhere I read is that when the temperature of the input water drops below 70f, waste water increases and your output decreases.

Why does lower TDS water coming out of the membrane not make sense?

 

[Sleepingtiger]

Why does lower TDS water coming out of the membrane not make sense?

What the tds reading out of the membrane when it’s cold vs when it’s optimal temp of 77f?

 

[Mike konesky]

Low temp=worse product to waste, better tds, lower production. 5ppm
Higher temp= better product to waste, worse tds, higher production. 11ppm.
Another note if you end up using the inline heater and have a booster pump: make sure you turn pressure back down before running 55 degree water again. You will go way over pressure.

 

[KStatefan]

What the tds reading out of the membrane when it’s cold vs when it’s optimal temp of 77f?

In the winter I get 99% rejection and in the summer 98%. That doubles the di resin life in the winter. Where did the optimal temp of 77 come from?

 

[Mike konesky]

In the winter I get 99% rejection and in the summer 98%. That doubles the di resin life in the winter. Where did the optimal temp of 77 come from?

77 comes from the manufacturer of the membranes.

 

[fish farmer]

How Temperature Affects RO Water Production

Every year, thousands of dollars are wasted on unneeded membrane replacements because hobbyists overlook the negative effects of cold water on their reverse osmosis (RO) system performance. Assumptions are generally made that their membranes have fouled, when in fact the temperature of the feed...

aquaticlife.com

 

[KStatefan]

77 comes from the manufacturer of the membranes.

Not that is an optimal temperature just the temp it is tested at.

 

[Gtinnel]

I never heat my source water either. I prefer the lower tds coming out of the membrane to save on my di, even if it means a little more waste and a slower production rate.
There is also the chance that if you over heat your source water you can instantly destroy your membrane.

If your only goal is to reduce the amount of water going through your pre filters why not look into adding an extra membrane.