shopping for RO/DI

[cone9]

I've used distilled water for some time as I have had a distiller at the office. It's now broken and would like to switch to RO/DI. I can probably waste water and buy filters for the electricity cost to heat the water in a distiller. After laborious searching over the sites of the better quality unit I've decided you BFS-161 gives the most bang for my buck(eyes). I live in NE Ohio.
Before I order I have a few questions.

The local Culligan dealer tells me our city supply is about 400-450 TDS. I'll only need about 15 gallons RO/DI per week. I'm pretty sure no chloramines are used - I'll check for certain before I order. It seems to me that a glass of tap water in the winter is a lot colder than in the summer(why? - the pipes travel underground through earth where there is little or no seasonal temp change) - but I've never used a thermometer to check the difference.

1- Would an adjustable flow restrictor be best to tweak that to compensate for summer/winter temp variation or is that not enough of a difference to matter?

2- Given an incoming TDS of 450 would you have some idea of the lifespan of the various filters?

3- Does this system have a valve to draw off RO for drinking before the DI units? If not, all I need do is place it a tee in the line between the RO and DI with some tubing and a shut off(?).

4- Flush valve/kits. Any real value to this? Doesn't it just allow all incoming water to flow past the membrane with no permeate generated? If so, could you not do the same by just completely opening an adjustable flow valve?

Thanks

[BuckeyeFS]

Good questions Dave - I'll answer them in order.

1. Adjustable flow restrictors are a nice feature for the advanced user. Remember that output from the RO is most affected by temperature and pressure. So when tap water temperatures drop in the winter, your waste to permeate ratio will increase. You can compensate for that with an adjustable flow restrictor. But you need to be careful that you don't close the adjustable restrictor too much. Maintain at least a 3:1 waste to permeate ratio. We used to put flow restrictors on all our systems, but we found that no matter how well we spelled it out in the instructions, we still had folks that would close the adj flow restrictor all the way to maximize (short-term) permeate output.

2. Regarding the life of the filters, it is difficult to tell. Your choice of a high rejection membrane (96 to 98%) is a good one. If your tap water is 400 ppm, your post RO numbers will be about 10 ppm, and your di resin ought to last you about 600 gallons. Please check the FAQ's on our web page re how to know when to change your filters.

3. Buckeye Premium system do have a valve as you describe (aka "a DI bypass valve"). Your suggested plumbing configuration is right on the money.

4. Right again. The flush valve provides a simple way to bypass the flow restrictor. After you spent 5 minutes adjusting the flow restrictor to 4:1, you'll probably not want to use it to flush the membrane. You could, but a separate valve is more convenient.

Let me know if you have additional questions.

Russ @ BFS

[cone9]

I set up my BFS-161 Premium Series 75 gpd RO/DI System today.
Quite simple. TDS for the tap water in is 418, RO is 18, DI is 0 - I'm happy!

Nice guys to deal with.

[BuckeyeFS]

Thanks Cone - we'll be here if you have any questions/need help.

Dave @ BFS