# Okay To Mount Needle Valve Before Solenoid?



## freph (Apr 4, 2011)

Putting a solenoid before the needle valve has the benefit of not putting pressure on the needle valve itself constantly. Solenoid before needle valve means shutoff of gas before it hits the needle valve if it's off.


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## oldpunk78 (Nov 1, 2008)

It's fine.


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## kevmo911 (Sep 24, 2010)

Yeah, it'll work fine. It's actually nice, in that it solves the issue of the tiny Mouse outlet having to support a relatively massive needle valve.


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## AaronT (Apr 11, 2004)

kevmo911 said:


> Yeah, it'll work fine. It's actually nice, in that it solves the issue of the tiny Mouse outlet having to support a relatively massive needle valve.


That was pretty much my reason for wanting to do it this way. 

Thanks for the reassurances guys.


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## Bettatail (Feb 12, 2009)

better not.
there are couple reasons as on the pneumatic circuit, the on/off valve(in this case, a solenoid) is always placed before the flow restrict/control valve.
1. once the solenoid valve open, there is "rush" of pressured air to fill the other side of the solenoid, instant air pressure increase may cause trouble. If the solenoid is before the needle valve, the needle valve can act as flow restrictor to prevent this "rush" to the rest of the air hose space.
To place a needle valve before the solenoid is fine only if the cavity volume between the needle valve and the solenoid is small, so with only limited amount of pressurized air in this cavity. once the solenoid open, it doesn't "push" too much to the rest of the air hose space or create trouble.
2. water issue, if check valve fail, the water always gets into the needle valve first, but hard to go through needle valve(then reach the solenoid) because the orifice is too small. If solenoid after the needle valve, the water gets in the solenoid first, that is what we don't want to see.


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## AaronT (Apr 11, 2004)

Bettatail said:


> better not.
> there are couple reasons as on the pneumatic circuit, the on/off valve(in this case, a solenoid) is always placed before the flow restrict/control valve.
> 1. once the solenoid valve open, there is "rush" of pressured air to fill the other size of the solenoid, instant air pressure increase may cause trouble. If the solenoid is before the needle valve, the needle valve can act as flow restrictor to prevent this "rush" to the rest of the air hose space.
> To place a needle valve before the solenoid is fine only if the cavity volume between the needle valve and the solenoid is small, so with only limited amount of pressurized air in this cavity. once the solenoid open, it doesn't "push" too much to the rest of the air hose space or create trouble.
> 2. water issue, if check valve fail, the water always gets into the needle valve first, but hard to go through needle valve(then reach the solenoid) because the orifice is too small. If solenoid after the needle valve, the water gets in the solenoid first, that is what we don't want to see.


Yeah, that makes sense.

So what IS the solution then? Do you have a custom manifold tapped for an 1/8" NPT outlet?


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## Bettatail (Feb 12, 2009)

there are three solutions for your setup:
1. get a different solenoid, now the available choice of solenoid is Burkert 2822 low power consumption solenoid in stainless steel.

2. find a 10-32 stainless steel 10-32 thick wall, hollow bolt or screw, so you can connect the manifold outlet(10-32) to the pipe bushing with this bolt/screw, the bolt/screw still hold pretty well due to it is thick wall. 
I found some of these screws, only 1mm hollow/orifice, need a 3/8" heavy duty bolt cutter to take out the screw heads, so you know how sturdy this piece is.

3. metal work the manifold, poke a UNF port on it and find a right size adapter to connect it to the Ideal needle valve. (this option is not less than likely, need tools and know how)


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## Bryanmc1988 (Apr 3, 2012)

you can tap a 1/8" port your self as i have done the same on my own manifold which i have a clipared also


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## oldpunk78 (Nov 1, 2008)

AaronT said:


> Yeah, that makes sense.
> 
> So what IS the solution then? Do you have a custom manifold tapped for an 1/8" NPT outlet?


I would recommend just trying it 1st before you start looking for a solution to a problem that may or may not exist. What betta is talking about is viable but not so much in a really small, relativity low pressure system.


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## Bettatail (Feb 12, 2009)

AaronT said:


> Yeah, that makes sense.
> 
> So what IS the solution then? Do you have a custom manifold tapped for an 1/8" NPT outlet?


I don't offer the custom made manifold any more, take too much time to make:icon_sad:


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## Bettatail (Feb 12, 2009)

oldpunk78 said:


> I would recommend just trying it 1st before you start looking for a solution to a problem that may or may not exist. What betta is talking about is viable but not so much in a really small, relativity low pressure system.


+1, you can try it, the solenoid after the ideal valve, but please make sure the fitting space is really small so not much pressurized air store between.
(30psi air pressure differential still be big trouble if in large amount and short time release)


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## AaronT (Apr 11, 2004)

I might go ahead and try it then. I plan to thread the manifold directly into the Ideal valve so that's about as short as I can make the connection. I'm also only running 15 psi and the end of the line is open and feeds into the return pump of my sump so back pressure shouldn't be an issue. The only issue I can see is possible cavitation of the pump impeller.


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## AaronT (Apr 11, 2004)

The 6011 I have is a 24 volt AC. The power supply I got outputs 24 volt AC at 50 watts. Could that also be contributing the the excessive heat? 

It's hard to find a 24 volt AC adapter (wish I'd known this) let alone one with the 400 ma output I'd need to get the output just right.


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## KTern (Mar 2, 2012)

Betta is against hooking the solenoid after the metering valve but with the Parker H3, I like the looked of it being before the solenoid and it is easier to turn and read the knob on the valve. It has been running for about a month or 2 now with no problem. Here is my setup that i hook it up to a cerges reactor


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## Bettatail (Feb 12, 2009)

KTern said:


> Betta is against hooking the solenoid after the metering valve but with the Parker H3, I like the looked of it being before the solenoid and it is easier to turn and read the knob on the valve. It has been running for about a month or 2 now with no problem. Here is my setup that i hook it up to a cerges reactor


the cavity space is small between the solenoid and the metering valve, so I guess it is ok.

but I am not sure why you want to hook it up this way, swap the places of them it will be better. :icon_lol:


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