Solenoids for water control


Thread Starter


OK disclaimer first
Not a professional, novice looking for help.

What I am trying to do:
I am trying to automate a misting and fogging system for an amphibian display vivarium. I have a small diaphragm pump (Aquatec CDP 6800) and am working with ¼ OD tubing and almost all ¼ push connect fittings and a couple of 1/8 NTP threadings. I then need to split the water coming from the pump. 1 path leads to misting nozzles. I am trying to use a normally closed 24VDC 4.8 watt solenoid for this. After the water had misted a normally open solenoid is used to release the pressure. This stops the nozzles from dripping in theory. The other path leads to a fogger. It is also controlled by a normally closed 24VDC solenoid. This solenoid when open fills a reservoir that contains a small ultrasonic fogger (the type for ponds and parties) Water enters the reservoir and overflows to keep the water a consistent height and then drains back to a holding container below. All of this is controlled by a programmable timer outlet that can independently turn on and off 5 separate outlets with accuracy the minute.

The problem:

The solenoids I am using do not seem to be able to consistently completely seal the water. 1 solenoid going to the fogging path seems to work fairly well, but the other solenoid leaks a bit so when I am trying to fog, I get some dripping out of the misting nozzles. In addition when I try to mist, the last solenoid that is used to release pressure does not seem to hold pressure very well and also leaks. So I cannot get good pressure to keep all the misting nozzles making a good clean spray without dripping.

I am also highly space constrained so you can imagine all this rats nest of adapters, 3 24VDC wall warts and 3 solenoids is a mess. It all has to fit in a 18 x18 x6 inch space above the vivarium which also contains 3 lights, computer fans for circulation and cooling and the programmable 6 outlet strip.

I am assuming I just made some sort of mistake and have not used a properly speced solenoid. Could someone please let me know what I need to look for in a solenoid?

Second as said the space is constrained and I have a feeling that if I could just find the right words I could find a part that would work much better. Is there such thing as a potable water safe solenoid that can handle the pressure of my pump (I think about 150PSI max) that will split water into 2 paths that can be independently controlled and also vent? I know this is common with pneumatic solenoids.

Here are some pictures to give people an idea of what I am working with.

Curt Wuollet

You may be getting the drip from relaxation in the plastic lines or from gravity if the piping is above the nozzles. 150 PSI is quite a bit for a plastic system and valves, perhaps not from a burst standpoint, but for expansion and contraction, I would look at small industrial solenoid valves or even washing machine and dishwasher parts since they are much cheaper. Noisy, but they withstand pressure well. And they will be more resistant to seat cutting than the plastic valves.

not all solenoid valves would be suited to your app, what is the model of the ones you have?

get a electronics/ham sort of a fellow involved to clean up the wiring mess, and consolidate the power supplies into a single transformer supply.

drippage can be sorted out partially by how you route the tubing and whether or not you can turn off the pump etc.

there are also multiport valves that allow port sequencing, but they are not cheap.
My 150 PSI mark may be a little high I was being cautious. the pump actually says that its burst PSI is 125 PSI. What I know is that many in fact almost all people working with vivariums use a similar system. They use plastic because metals might leach into the system and kill plants or animals. The vivariums are closed systems and most of the time the only way water leaves is through evaporation. So if a metal was leaching into the water it would just build up in concentration over time.

Each misting nozzle has a check valve in it and all the other people working with them do not complain of gravity causing dripping.

Also I meant to say that I am using 1/4 OD tubing but when I pasted in from MS word it changed the character on some web browsers.
In my case the pump is only on when I want to move water, either the misting nozzles or the fogger is on. So I am able to turn off the pump. All of my discussion above was during pump on operation when it was suppose to be on. When I turn the pump off the water stops and dripping stops.

As for the solenoids, last night I think I discovered that I had received bad information on my normally open solenoid and it in fact it something completely different.

These are the normally closed solenoids I bought.

<b>moderator's note:</b> when copying and pasting long URLs, delete any spaces inserted by the forum software.

This is what I thought was a normally open solenoid

On the misting side what I really wanted was something like this I think.

I thought that unit would be able to combine both solenoid operations into 1. however I was never able to find anything like it in plastic. Also would be better with 1/4 OD push connect, or 1/8 FPT fittings. Also it would work better if it was AC current then I wouldn't need a transformer.
they might work, but unless the supplier warrantees a tight shut-off requirement at the rated pressures there are no guarantees and you are at the mercy of the buyers "bill of rights."

industrial solenoids use a variety of methods to achieve tight shut-off