Solenoid Valve

[1diverdown]

here's my dilemma....

i just rigged my calcium reactor so it's water supply is run via gravity feed. i got tired of rio 50 pumps constantly dying on me. i want to now have it so that the reactor is only on during the 'lights on' period, and thus i need a solenoid valve that can turn on during that time. it will also have to be sized to handle tubing that is typically found on ro/di units (refridgerator water line tubing). i called spectrapure to order one of their solenoid units, but was told that saltwater will destroy these units (and anything made of brass). is anyone using a solenoid that can handle 1/4" tubing and is saltwater proof?

thanks
Doug

[Yam]

I don't think its possible. I've never seen a solenoid that will seal tight without pressure. What you need is a motorized ball valve, with reducers etc. to fit 1/4" poly tubing. It'll be completely saltwater safe.

-Yam

[1diverdown]

Yam....

thanks for the tip...do they make ball valves that small????

Doug

[Yam]

I have seen 1/2" motorized ball valves. You can easily reduce that down to 1/4" for use with push lock fittings. I would only trust festo fittings, or John Guest in a pinch. I've had the home depot cheapos crack on me.

-Yam

[armygreen11]

A quick search on McMaster yeilded this part number: 7876K13. Just go to mcmaster.com. Delrin (plastic) body, rubber seats, 1/4" valve, 24VDC so you'll need a AC/DC converter (they have those too, just make sure you get one that can handle the current draw.) It also said it has a 0psi minimum differential pressure, so you shouldn't need a pressurized line to get it to seal.

[armygreen11]

My bad, it can be ordered in 120VAC. It's also a normally closed valve, so in a power outage, it'll shut off flow.

[jdieck]

There is an issue wioth using a solenoid for this job. I used the valve from Mc. Master and it works for a while, the issue is that the coil runs hot and the heat eventually precipitates calcium carbonate in the seat preventing it from sealing, I had to put it apart to clean it too often until I decided to switch to a Doser Pump on a timer.

[Tagareef]

Yes, aperistaltic pump would be the most dependable way to go.

Luis

[armygreen11]

Originally posted by jdieck
There is an issue wioth using a solenoid for this job. I used the valve from Mc. Master and it works for a while, the issue is that the coil runs hot and the heat eventually precipitates calcium carbonate in the seat preventing it from sealing, I had to put it apart to clean it too often until I decided to switch to a Doser Pump on a timer.

Good call. I didn't even think about that. I was just reading in a new copy of Machine Design magazine about why solenoid valves get hot. Seems it takes alot of current to open the valve, but only a fraction of that to hold it open, but with cost effective power management in the solenoid assembly, they just let the amount of current needed for opening though all the time, so whatever power isn't being used to hold the valve open is just lost to heat. Some company called Red Hat is supposed to have a new line of valves out with ASIC chips in the assembly to remedy this. I haven't looked into it any further though, sorry.

[rae gordon]

Why do you want to shut off the flow, wouldn't it be better to stop your co2 flow, thus reducing the output. I have not heard of anyone shutting the flow off.

[jdieck]

You are right but I think it mostly apply to solenoids that require pressure to close. With a unit to seal at no pressure like the one above it closes by the effect of a spring that pushes down the mag core against the counter seal so the coil has to keep the force against the spring all the time during which the solenoid has to be open.

Seems that most of this type of solenoids (Small orifice) are used for neumatic On / Off control and as such they are designed for intermitent work and heat is not an issue. I wanted mine open 12 hours at a time and the coild get so hot that I got burned a couple of times.
I was able to somehow reduce the heating by lowering the voltage to the minimum required for opening by the use of some power resistors and by cutting a couple of turns off the spring but although the temperature got lower it still was not low enough to prevent precipitation.

Diverdown:
I have a better suggestion that will work even better. Do you have a solenoid that will cut your CO2 in your CO2 regulator?
If so you do not need to stop the flow of water trough the reactor but instead just cut the CO2 supply via the CO2 solenoid, the water will go in and out but without CO2 to disolve anything the reactor will not have any impact in your PH at night.
The other advantage is that by not cutting the flow it will stay more stable and your trickling and adjustments will be reduced to a minimum.
If you have a PH controller just connect your timer in between the controler power output and the solenoid. The controller will call for the Solenoid to open when the PH will rise but the timer will keep the solenoid closed. As soon as the timer goes on the signal from the controller will pass to the solenoid and open it.
As long as the timer is ON the controller will operate normally.

Lot simpler IMO.

Good Luck.

[Tagareef]

rae has a good point. I would think that shutting down your flow with risidual CO2 in the reactor would or could "cook" your reactor media and be "milky" upon start-up if the ph didn't have a chance to come back up. Also, I would also be concerned that the water would stagnate sitting in the reactor for possibly 12 hours.

[jdieck]

Rae:

I'll better learn to write shorter posts! You beat me to that one.

[1diverdown]

whoa...this is the first day all week that i've had time to catch up, and it looks like i've missed a lot. first of all, thanks for all the info on solenoid valves. i had no idea! i was talking to another reefer about this situation and he said that the best thing to do is to just shut off CO2 flow at night, just like rae and jdieck mentioned. geez, sometimes the simplest methods are the last ones we consider.

Tag, you mentioned stagnating water. i use a Deltec 600S reactor so the flow and media are constantly moving.

would there be any other potential pitfalls to just shutting off the CO2? i already have a solenoid valve for the gas, and i run an IKS Aquastar computer, so controlling the solenoid would be a piece of cake. any suggestions would be most welcomed.

thanks everyone for the input
Doug

[moonpod]

I think the biggest pitfall would be difficulty in monitoring your CA and Alk output accurately...course if it's keeping up with your tank needs, then it probably doesn't really matter what it is specifically.

[jdieck]

Just meassure the effluent alkalinity after one to two hours the CO2 has started flowing

[Michael950]

1diverdown

Here is someone who did something similar.

Main page http://www.mistressreef.homestead.com

DIY Auto Topoff

[salsaking]

Hey Doug! Simple issue to fix! The PF1000 that I use from Deltec comes on via Neptune computer, when the lights come on in the morning. After about a minute of operation the Co2 is turned on via the computer. When the lights turn off for the night the opposite occurs. Co2 turns off via computer and then the Deltec system is shut off via the computer. I have x-10 modules that plug in via the outlets and then each device like the reactor and Co2 solenoid vavle are plug in via the x-10. Hope that helps. No problems keeping my calcium and Alkalinity balanced.

Hope this helps!!

SalsaKing

Check out the camera feed again!! It's up and running. The tank that is.

[salsaking]

Reading your thread more carefully I use the spectrapure solenoid valve and it has worked for two years!! If you give me a call I can guide you through your issues! I have the same set-up as you are wanting to accomplish.

It works great! no issues! Day in and day out it has performed perfectly! I can also tell you how to get a better feed than the pump feed issues you were having before.

Salsaking