Hot water and RO/DI, stumped...

Kinda stumped on this one...I have upgraded my tank to a 120 gallon from a 50 gallon. I have a Typhoon III RO/DI. Already I see it's gonna be a challenge to keep up with the top-offs, we live in Florida and there is alot of heat and ventilation in the tank encouraging evaporation. So I want to setup an auto-top off in the sump, but my concern in that our water is run through the attic, and I would say at least the first 2-3 gallons of "cold water" is actually very hot, like hotter than our water-heater water temperature. So I'm worried that this would damage the RO/DI, since with an auto-top off I think it would always be pulling from that first few gallons of hot water in the line. Until now, I have always cleared the hot water out of the line by running the washing machine till the water comes out cold (the Typhoon is spliced into the washing machine supply). Any thoughts? Am I being paranoid? I've sent an email to AirWaterIce but havent heard back yet, it has only been a day though. One idea I had was just hooking up a long, coiled garden hose in between the water supply from the house and the RO/DI, sort of a reservoir that would give the water temperature some time to cool-off before entering the filter. Don't know how sensitive those float-valves are though, it they fill very small amounts all the time, in which case I think that would work, or large amounts less frequently, in which case it would still pull from the hot attic water. Anyways, thanks for any input, sorry for the long post.

 

i don't think you have to worry, mine is used to be hooked up to a shower and would have hotwater go through it. im not sure what exactly happens but the water passes through it faster when warm

 

I've always heard not to run hot water through an RO unit. It will damage the membrane.
I guess I'm missing the issue??? Is the supply for the RO hot water?

 

I have a Typhoon III as well and I remember reading in the manual that the system runs the best with water at 70F..(don't quote me) but i'm guessing that anything above or below that you'll get less GPD or something like that...but with the extreme heat, it does make sense that your membranes might get damaged. Hope this helps a little!!

 

If the tubing feeding the R/O is running across the attic and not the output water then you will have to use about 400 ft to hold a gallon of water if its 1/4" O.D and you may want to insulate it in some type of foam cell to keep it from condensation in the attic . As for the temps the perfect water temp to enter the unit is 76F this allow the pores of them membrane to dilate to proper size or so the experts say that optimal under laboratory conditions . I myself have set up about 12 units in Fl. and Ms. and ALa. and all being on slabs I connect the unit to the cold water feed at the water heater and run the output water into the attic then to the tank's sump.. I still insulate them though.. But that little water across a normal house will not harm anything enough to worry about it if thats what you have with the supply water to unit running across a 100 ft or less attic? And if its the output then no problem at all other then maybe condensation ?

 

Thanks for the replies! Kogle, it's not that the RO is hooked to the hot water line, it's that all our water lines are run through the attic, and I'm pretty sure where the city water enters our house is on the opposite side of the house. So the water in the cold water line sits in the pipes in the attic when not in use, and gets really hot because we live in Florida and its freaking hot down here most of the year. I've never measured the temp that comes out, but the first say 30-40 seconds of running the cold water in our house feels hotter than our hot water, before it all clears out and we start pulling cooler water from the ground supply. So I'm just concerned that running that through the RO system would damage the membrane. I have read some stuff on other threads indicating the big concern with running an RO directly from a water-heater supply, is that A) the temperature is constantly too hot for the filter to run properly and B) water-heaters concentrate minerals that the filter will have a harder time clearing. I'm just concerned that the high temp that we get in our cold-water line for the initial few seconds might damage the filter. Thanks again!

 

Just mount a self tapping saddle valve on the water heater's cold suppl it will say COLD on the heater the 3/4 line with the valve on it. Just put the saddle valve on the pipe before the water cut off . With a R/O running at 4 to1 waste to product water then you will be fine . You have no water lines coming out of the slab near to the water heater ? The main water from meter comes in under ground somewhere and has to come up through the concrete slab at some point.. If its a newer Home In Fl. ? then that line will be usually near to where the A/C air handler is setting and the water heater. Bit not always . You'll have to look for that.