RO/DI pressure only 32

Slightly slower making of ro/di water. Will not harm anything.

 

It will cause the membrane to get clogged and restrict the flow due to the lack of pressure and it will also not be the purest water (info. directly from manufacturer manual). They recommend between 60 psi. on the unit I have. and I just bought the booster earlier today because I'm ready to get this unit running (NEED WATER) and want to do it right the first time I hook it up. Not to mention running under 40 psi. waives the warranty on it.

 

Sorry tgood (and BRS) I quoted the wrong price. I paid $130.00 for my booster pump. Not the $230.00 I quoted earlier. And tatted4ever, one of the water gurus will probably chime in but, if I'm not mistaken, low pressure causes the filters and membrane to work harder and will therefore result in you having to replace them more frequently.

 

Well according to what AZDesertRat told me, the slightly lower pressure will just reduce the gallons per day. Since the Spectrapure Flow Restrictor is adjustable, you just have to adjust it to get a 4:1 ratio of waste water to ro/di water. This will ensure you are getting the right amount of water to keep the membrane flushed. Unless I totally missed the boat on what he told me.

Here's a direct quote from a thread he posted on:
"The flow restrictor was not sized correctly and you have only been getting about a 1:1 waste ratio (not rejection rate) so the membrane is plugged and shot. You need a minimum of 3:1 waste to permeate and 4:1 is recommended.

Your rejection rate (removal efficiency) is only 84.8% which is way below the recommended 96-98%. No wonder your DI is exhausted, it has been doing most of the work.

With a new RO membrane you should see a RO only TDS of about 5 so the DI will last and last. With the Spectrapure membrane it will probably be a lot lower than 5 actually, my tap TDS is 600+ and I'm seeing a RO only TDS of between 4 and 5 myself.

With 57 psi and 69 degree water and a TDS of 278 you should see almost exactly 75 GPD out of a 75-90 GPD RO membrane and at 98% rejection.

If you get a new membrane make sure you get the $4.99 capillary tube flow restrictor too and take the time to trim it correctly once the system is flushed initially. Its easy and takes only about 5 minutes one time."




And another post of his:

"Spectrapure uses Dow filmtec membranes. The difference is they put them through a special proprietary treatment process to further improve both the GPD and the rejection rate then they bench test them and on their Select series they provide a written performane guarantee. They start out as the same Dow Filmtec then get improved upon.

The pressure rating is an often misunderstood thing. Itdoes not matter if its Dow Filmtec, GE water, Applied Membranes or several others. A Dow 75 is rated at 75 GPD at 50 psi and 77 degrees F or 90 GPD at 60 psi and 100 GPD at 65 psi. A 100 GPD, GE Water or Applied is rated at 100 GPD at 65 psi and 77 degrees F, 90 GPD at 60 psi and 75 GPD at 50 psi.

They are all almost identical and will produce the same amount of water at the same pressure, all do 75 GPD at 50, 90 GPD at 60 and 100 GPD at 65, its just a different way of advertising or a gimmick if you will.

You don't have to have 65 or 60 psi, you can have 40 or 50 or 60 or even 90 with any of them and get almost identical performance with the exception of the tested Spectrapure membranes which do for some reason produce more and at a higher quality, their treatment and testing is worth the money."

 

Always go by your products warranty suggestions, IMO. Not that they could prove anything if you disregarded it, but there is a reason why it is there in the first place.

 

First of all 32psi is too low for your whole house. What will happen is when someone is taking a shower & another person turns on the faucet, you'll burn yourself. I have a well and my pressure is 60psi. The pressure on your water pump is adjustable & is very easy to do. Your pressure switch should turn on at 25 or so & turn off at 55 by default. My parents had a dumb plumber that went by their house & he screwed it all up & it would turn on way too soon & their water pressure was shot. I made the adjustment & it's now perfect.

Here's a video on how to adjust that I found. The pressure switchs are standard on how they adjust.

 

30 psi is common for a domestic well system, most pressure switches are factory set at about that point to reduce cycling of the well pump. I wounld NOT readjust the pressure switch as it can cause problems with the well, pressure system and pump, always consult the driller or pump installer when doing this. Your power requirements and bills will go up accordingly too.

Yes 32 psi is low for a RO membrane, 40 psi is about bare minimum. A booster pump is a much better option and it does not cost much at all to run a 24v DC pump at a few watts only when making RO/DI water compared to a 1HP or larger 220v AC pump every time it cycles on an doof for any usage.

Low pressure not only reduced GOD but it also raises the amount of waste and greatly lowers the rejection rate or removal efficiency. Adding a booster pump reduces the waste, increases the GPD and increases the removal efficiency or rejection rate, its a win, win, win situation.

 

Yeah, my dad used to be a contractor and build houses so he knows his $^#!.... our pressure is 40 min. - 60 max. however at the RO/DI it only gets 32. Rather than try and argue with my dad I just decided to suck it up and buy the booster also. It is on it's way so my unit should be installed by the beginning of next week. +1 AXDesertRat on the domestic well system and not adjusting anything!!

 

Well I answered my own question... I just hooked it up to the same faucet again because I really need some water and the pressure is now 40 and climbing so I think it just need to build up some pressure in the RO/DI unit which is why it was only at 32 psi. I'm debating whether or not to cancel the order for my booster now that the pressure is 40+....? Any suggestions, I would really love it if I can be good w/ 40psi and get my 150 bucks back for that booster.

 

40 is about bare minimum, it will give you approx. 58 GPD if the flow restrictor is trimmed correctly and you have 77 degree water available. If the water is colder the GPD drops off significantly. Say its 67 degree water then you would get 47 GPD, 57 degrees would be more like 39 GPD etc.
Boosting the pressure is a much better option than trying to warm the water if higher GPD is desired. Blending or mixing hot an cold is a surefire way to melt a RO membrane since they cannot take any temperatures over 113 degrees F.

Spectrapure has a worksheet where you can work out the various scenarios and get a very close GPD number:
http://www.spectrapure.com/CALC-FORMULA.pdf

They have also posted some test results on why a booster might be a good idea since it also improves the rejection rate (removal efficiency) and not just the GPD.
Another perspective on Booster Pumps... - Reef Central Online Community

Note that there was a 1.2% increase in rejection rate bewteen 35 psi and 85 psi. This is significant when you consider for every 2% you increase the rejection rate you DOUBLE the life of your DI resin. It does not take long to pay for that $130 booster pump with DI resin savings if you make much water at all.