Making RODI with Warm Water?

[Buford25]

With the polar vortex passing through the Midwest right now I had a thought that led to a question…

Has anyone ever made their RODI water using lukewarm water? Is there an issue doing this? In theory this would help with heating the water up faster to tank temperature with ground water being colder this time of year.

Does anyone have any experience with this; see any issues doing this etc..?

 

[WVNed]

I have done it in the winter. No issues for me.

 

[NinnJinn]

Never run hot water through a RO membrane.

Water over 113 degrees will melt the plastic film instantly. This goes for trying to blend or temper the water by mixing hot and cold too.

Remember being in the shower and someone flushes the stool or starts the clothes washer? You got your tush scalded!

The same thing happens with the RO membrane and its not worth the risk. Colder water affects GPD output but it can be offset by higher pressure. At times a booster pump is a good idea if you have colder waters. Another reason to stick with the colder water is it filters better and will make the membrane more efficient since colder water is more dense and the dirty stuff does not try to pass through the membrane as much as with warmer water.

 

[Buford25]

Appreciate it. I was not planning on running hot water through only raising the temperature slightly, around 55-60 degrees. I'll more likely than not stick to just cold. This time of year the water is COLD though.

 

[redfishbluefish]

Fully agree....no hot water!

 

[rushbattle]

This definitely helps with production volumes through the membrane, but how are you going to heat the water? It’s not a good idea to mix cold tap with hot water via valves, if you slightly iverheat the membrane it’s permanently ruined and you have to replace it. And the unit is only rated to 90°F, beyond that and it can be irreparably damaged and cause a leak and consequent flood.

 

[Scooter.B]

It can be done BUT, the hot water will break down the RO Membrane. Which is not good and could be exspensive over time.

Using water on the warm side would be OK. I would say no more than 75°

 

[Justin Cook]

I have a bucket that I run a spiral of 3/8" pipe through. I heat the water in the bucket and run the water going to the RODI unit through it. It's not nearly a effective as I'd like but it does warm it a few degrees and that makes me feel a little better by reducing the waste water/production water ratio. I used to run 1/4" through an old crock pot in a similar fashion but one time I turned the crock pot on, got distracted and then turned on the water quite a bit later. That cost me a membrane so I scrapped the crock pot in favor of the other system.

 

[Buford25]

The RODI system I have screws directly onto the faucet. I normally attach the hose, open the cold water spigot and away we go. Once I have the desired amount of water in a five gallon bucket I’ll throw a heater in bring the water up to temp, add the salt, dissolve the salt while remaining water temp and use.


If I open the cold water spigot and the hot water spigot a little to raise temp slightly, technically speaking, it would be the roughly the same temp as the ground temp in the summer months..