RO solenoid

larryfl1 · 06/28/2009, 05:41 AM

Hi,

who makes the best solenoid valve to purchase to be used for RO top off? mY controller will be controlling it so i only need the solenoid valve

LEGENDARY_ENG · 06/28/2009, 06:24 AM

The best are made of 314 or 316 stainless steel with a orfice size the same as the I.D of your tubing you are using. There are cheap ones that are made of plastic with a very small orfice that will damage your ro unit or reduce the amount of water going threw your r/o.

larryfl1 · 06/28/2009, 08:40 AM

who would you recommend to buy it from?

GlassReef · 06/28/2009, 08:44 AM

A number of us use this one: McMaster-Carr

Here's a pic of it among some of the other parts I used in my ATO:

LEGENDARY_ENG · 06/28/2009, 09:14 AM

The ones from Mcmaster have a very small orfice 1.30mm the inside diameter of tubing is 4.25mm so you will restrict the flow almost 3/4 percent they are very cheap valves and will fail all metal low grade parts inside. do not install after ro membrane as they will fail sooner.

jdieck · 06/28/2009, 10:07 AM

Quote:

Originally posted by LEGENDARY_ENG
The ones from Mcmaster have a very small orfice 1.30mm the inside diameter of tubing is 4.25mm so you will restrict the flow almost 3/4 percent they are very cheap valves and will fail all metal low grade parts inside. do not install after ro membrane as they will fail sooner.

The flow restriction depends on the pressure drop across the valve which depends not only on the diameter of the orifice but also on the velocity of the fluid which depends on the flow.

a 75 gal/day unit will have a flow of 0.052 gal/min. The valve has a Cv = 0.170 gal/min for a 1 psi pressure drop across the valve
So the pressure drop will be less than 0.3 psi which is insignificant and way below the normal back pressure of an RO/DI check valve normally used on the output of RO/DI systems which require 1 to 4 psi to open.
In simple terms, at the low flow of a normal RO/DI the restriction is very insignificant.

Regarding their use in RO/DI systems:

Quote:

"Polypropylene body has higher chemical resistance than PVC and CPVC and is suitable for deionized water and high-purity fluids. Ideal for existing polypropylene systems."

I have been using one in my RO/DI system for the last 5 years without any problem.

In summary, it is suitable for the purpose although for different reasons (start up purity, reliability of float switches, etc.) I will not use any automated system to supply top off directly from an RO/DI system to the aquarium but rather to manage the automation in refilling an RO/DI reservoir.

larryfl1 · 06/28/2009, 10:18 AM

so is mcmaster the best one to get? if not who else ?

macmaster looks like prolypropylene....

also if i want to put a backup up 1 after another..in case of failure...would that work?

jdieck · 06/28/2009, 11:26 AM

Quote:

Originally posted by larryfl1
so is mcmaster the best one to get? if not who else ?

macmaster looks like prolypropylene....

also if i want to put a backup up 1 after another..in case of failure...would that work?

It will be helful to know exactly what are you trying to do or setup.

larryfl1 · 06/28/2009, 11:39 AM

i will have an ro line coming to the tank...

i have a profilux with float swtich...when needing refill i will open the selonoid and when float says high enought it will close....

it will be on the output side of the RO unit...as the RO unit is across the house...

my concern also is if the selonoid fails i dont want a flood..thats the thoughts around 2 of them

jdieck · 06/28/2009, 12:04 PM

Somethings for you to consider.
The first batch of water produced from an RO/DI unit after it has been closed will be contaminated. This is the main reason why it is not advisable to use an RO/DI for top off as relatively small quantities will be produced in it batch if used for replacing evaporation.
Purity wise it is better to use an auto purge sytem (which is expensive or impractical for frequent ON/OFF) or a large reservoir with two floats, one to turn on the system when the reservoir is almost empty and another one to turn it off so large batches of water can be produced thus greatly diluting the initial impurities.
You can then use a peristaltic pump with a timer from the controller or with a regular top off to maintain the water level in the sump.

The usual weakest link in a top of system is the floats but in any case when atomating an RO/DI system, a good safety feature will be the use of an ASOV valve in the RO/DI unit and a float valve at the point were the water enters the reservoir. If any element of the top off fails the float will cut the product water from the RO/DI and the ASOV will shut off the water supply to the RO/DI.

LEGENDARY_ENG · 06/28/2009, 12:29 PM

you will not lose pressure but flow (gallons per minute) with the restriction of the decreased orfice size. The decrease in water volume going to a ro/di will have certain effects on the proformance of the filters and cleaning of a ro membrane and decreased water production.

jdieck · 06/28/2009, 12:43 PM

Quote:

Originally posted by LEGENDARY_ENG
you will not lose pressure but flow (gallons per minute) with the restriction of the decreased orfice size.

I do not know other means of restricting flow other than the pressure drop trough the orifice (or back pressure that the upstream flow will see) which in this case is neglegible.
Note that the flow is restricted in this case by the capacity of the RO/DI production, not the orifice as it is a lot lower than what the orifice can handle regardles of it's size.

larryfl1 · 06/28/2009, 01:16 PM

my RO unit is across the house with ro line underground until the tank...

i dont think i have room for the storage tank unless i put it where the ro unit is... and let the peristalic pump pull it 40 feet if it will??? then i can put a big drum in the garage....

thoughts??

the other option i also have is to put 2 solenoids that are on a y from the ro clean water by the tank....
let the first solenoid open for 20-30 minutes ...and let that line run outside behind the tank...after 20-30 minutes that valve closes and the one to the tank opens... at that point the ro water is good quality....

whats your thoughts???

jdieck · 06/28/2009, 05:16 PM

The two solenoids option is good and you will need to purge for only about 5 minutes but the issue will be the waste od DI resin wasting 5 minutes every time you turn on if turning on and off is too frequent.

The good news is that a peristaltic pump like the litermeter II can pump water up to 60 ft high so I do not think it will have any problem pumping trough 40 ft of line mostly horizontal.

06/28/2009, 05:41 AM	#1
larryfl1 Registered Member Join Date: Jun 2009 Posts: 797	RO solenoid Hi, who makes the best solenoid valve to purchase to be used for RO top off? mY controller will be controlling it so i only need the solenoid valve

06/28/2009, 08:44 AM	#4
GlassReef Got Reef Join Date: Mar 2006 Location: Weeki Wachee, Florida Posts: 2,501	A number of us use this one: McMaster-Carr Here's a pic of it among some of the other parts I used in my ATO: __________________ Tom No matter how much you try to push the envelope, it remains stationary. Last edited by GlassReef; 06/28/2009 at 08:50 AM.

06/28/2009, 12:04 PM	#10
jdieck Registered Member Join Date: Dec 2002 Location: Maumee, OH Posts: 15,673	Somethings for you to consider. The first batch of water produced from an RO/DI unit after it has been closed will be contaminated. This is the main reason why it is not advisable to use an RO/DI for top off as relatively small quantities will be produced in it batch if used for replacing evaporation. Purity wise it is better to use an auto purge sytem (which is expensive or impractical for frequent ON/OFF) or a large reservoir with two floats, one to turn on the system when the reservoir is almost empty and another one to turn it off so large batches of water can be produced thus greatly diluting the initial impurities. You can then use a peristaltic pump with a timer from the controller or with a regular top off to maintain the water level in the sump. The usual weakest link in a top of system is the floats but in any case when atomating an RO/DI system, a good safety feature will be the use of an ASOV valve in the RO/DI unit and a float valve at the point were the water enters the reservoir. If any element of the top off fails the float will cut the product water from the RO/DI and the ASOV will shut off the water supply to the RO/DI. __________________ Did I write what I wrote? What the heck am I talking about! Well..... Nevermind. Current Tank Info: 225 gal reef, DSB, 40 g sump w/ LRT100 return, 37 g pre-sump, 3 MH 250 W 15K, 4 96 W PC dual actinic,ETS 1500 Skim.w/LRT70, 20 lb Ca R., 40 W UV, 1/3 HP chiller, two 350 W Htrs, Neptune II Cont., 330 P LR/ 330 P LS. 55 gal Refugium

06/28/2009, 12:29 PM	#11
LEGENDARY_ENG Registered Member Join Date: Dec 2008 Location: michigan Posts: 22	you will not lose pressure but flow (gallons per minute) with the restriction of the decreased orfice size. The decrease in water volume going to a ro/di will have certain effects on the proformance of the filters and cleaning of a ro membrane and decreased water production. Last edited by LEGENDARY_ENG; 06/28/2009 at 12:45 PM.

06/28/2009, 05:16 PM	#14
jdieck Registered Member Join Date: Dec 2002 Location: Maumee, OH Posts: 15,673	The two solenoids option is good and you will need to purge for only about 5 minutes but the issue will be the waste od DI resin wasting 5 minutes every time you turn on if turning on and off is too frequent. The good news is that a peristaltic pump like the litermeter II can pump water up to 60 ft high so I do not think it will have any problem pumping trough 40 ft of line mostly horizontal. __________________ Did I write what I wrote? What the heck am I talking about! Well..... Nevermind. Current Tank Info: 225 gal reef, DSB, 40 g sump w/ LRT100 return, 37 g pre-sump, 3 MH 250 W 15K, 4 96 W PC dual actinic,ETS 1500 Skim.w/LRT70, 20 lb Ca R., 40 W UV, 1/3 HP chiller, two 350 W Htrs, Neptune II Cont., 330 P LR/ 330 P LS. 55 gal Refugium

06/28/2009, 06:24 AM	#2
LEGENDARY_ENG Registered Member Join Date: Dec 2008 Location: michigan Posts: 22	The best are made of 314 or 316 stainless steel with a orfice size the same as the I.D of your tubing you are using. There are cheap ones that are made of plastic with a very small orfice that will damage your ro unit or reduce the amount of water going threw your r/o.

06/28/2009, 08:40 AM	#3
larryfl1 Registered Member Join Date: Jun 2009 Posts: 797	who would you recommend to buy it from?

06/28/2009, 09:14 AM	#5
LEGENDARY_ENG Registered Member Join Date: Dec 2008 Location: michigan Posts: 22	The ones from Mcmaster have a very small orfice 1.30mm the inside diameter of tubing is 4.25mm so you will restrict the flow almost 3/4 percent they are very cheap valves and will fail all metal low grade parts inside. do not install after ro membrane as they will fail sooner.

06/28/2009, 10:18 AM	#7
larryfl1 Registered Member Join Date: Jun 2009 Posts: 797	so is mcmaster the best one to get? if not who else ? macmaster looks like prolypropylene.... also if i want to put a backup up 1 after another..in case of failure...would that work?

06/28/2009, 11:39 AM	#9
larryfl1 Registered Member Join Date: Jun 2009 Posts: 797	i will have an ro line coming to the tank... i have a profilux with float swtich...when needing refill i will open the selonoid and when float says high enought it will close.... it will be on the output side of the RO unit...as the RO unit is across the house... my concern also is if the selonoid fails i dont want a flood..thats the thoughts around 2 of them

06/28/2009, 01:16 PM	#13
larryfl1 Registered Member Join Date: Jun 2009 Posts: 797	my RO unit is across the house with ro line underground until the tank... i dont think i have room for the storage tank unless i put it where the ro unit is... and let the peristalic pump pull it 40 feet if it will??? then i can put a big drum in the garage.... thoughts?? the other option i also have is to put 2 solenoids that are on a y from the ro clean water by the tank.... let the first solenoid open for 20-30 minutes ...and let that line run outside behind the tank...after 20-30 minutes that valve closes and the one to the tank opens... at that point the ro water is good quality.... whats your thoughts???