Hot water for Rinse

[Brent]

I wonder what the thoughts would be about using hot water for rinsing the RO. Seems to me that if the temp was near 110 - 115 it would flush better than cold permeate.

The reason for asking is the I've got a Steamaway that is supposed to dump 100 gallons an hour of 200 degree water. If I collected that and let it cool, I think I could get better and faster rinses, even better and faster washes too !

Anyone see a downside to this ???

[mapleack]

I'd think that'd work fine using the hot condensate, shouldnt be any different than permeate. I got a heating element for my wash tank, but haven't had time to install it, and no wiring directions came with it. :( For now I put 10 gal of permeate in my canner, heat it up to 100 deg, dump it back in the wash tank with a little cold permeate, bringing it all to about 90, then run the wash.

[802maple]

Hot water can be fine as long as you feather it in and change the temperature slowly as membranes don't like to be shocked. Just make sure your water doesn't have much sugar in it as sometimes that can happen from steam hoods.

[Brent]

Thanks, I did read about thermal shock a while back but did not connect the dots to what I am thinking of doing with the hot water now.

Last year's rig got too much splash in the hood and had 1% sugar going out the drain. I plugged it after I discovered that. I have not heard of anyone getting sugar from a SteamAway.

[RO_Guy]

I was told by a rep from CDL that the sodium hydroxide soap doesn't activate till the permeate reaches about 32ºc-34ºc. So the time it takes to reach that tepmerature is wasted. If you could cool the water to 30ºc or so, it would be perfect.

[TunbridgeDave]

I thought about using preheater water as well for rinsing, but after talking with Randy at Leader, I decided not to. If you have anything other than SS in your preheater or Steamaway like copper pipes and solder, DON'T DO IT!!!!!! The minerals leach out in hot water and you can clog up your membranes.

[Jim Brown]

Gentlemen; My RO has a heater in the tower and will recir the water/soap mixture untill temp get to 115 and then shuts down. I then change valves to my rinse tanks and flush with about 600 gallons of premate. Lapierre recommends that you do not go over 115 degrees or you may damage the membrane.
just my two cents

Jim

[TunbridgeDave]

I agree that a heater and a thermal cutoff switch is the best solution. Most of the new hp pumps generate sufficient heat even without the heater. But there are many machines out there w/o such things, like mine.

[maple connection]

The one thing I can add is to make sure your water does not get above 115 degree during the wash cycle like mine and my old coster R.O. is not protected with a thermo shut off switch so be careful. But warm water on a wash and rinse is the way to go if you have a supply of CLEAN warm water.

[Grade "A"]

Hot water can be fine as long as you feather it in and change the temperature slowly as membranes don't like to be shocked. Just make sure your water doesn't have much sugar in it as sometimes that can happen from steam hoods.

I have heard about thremal shock also. This gets me thinking, we wash the RO until the temp is 115 deg. then do a rinse with 40-50 deg water. This must not be to good for a membrane right?

[802maple]

I have heard about thremal shock also. This gets me thinking, we wash the RO until the temp is 115 deg. then do a rinse with 40-50 deg water. This must not be to good for a membrane right?

It is all right as long as you feather in the colder water and bring it down slowly.

[Brent]

I think this year, to avoid the thermal shock and to neutralize the alk soap, I'll add in some citric acid solution a few gallons at a time. That way the dump on the hill is not poluting and the thermal shock is gone. Just one more complication.