OT: Asco Valves

Tim Ganz · Jun 22, 2011

I have a water cooled extruder with many asco valves to control cooling to each zone. Many times when these fail tech just replace the top with all the guts and leave the bottom on the machine. I thought these were machined as a set? Can't this practice cause problems?

I know it has to be done sometimes to keep production running but some guys even do it that way on a pm and only replace the top.

What kinds of issues will this cause?

OkiePC · Jun 22, 2011

They are replacing only the solenoid and not the valve. It's been my experience that the solenoids are pretty reliable, so something unusual might be happening if you are seeing a large number of failures. The valves themselves are pretty reliable too, depending on the quality of the fluid they are exposed to.

I don't think it will cause any problem to only replace the solenoid, but it doesn't make sense to do that when the machine is down for scheduled preventive maintenance. That's just laziness IMHO.

Thomas · Jun 22, 2011

Fail mode

If these are similar to temperature control units that I have for a similar task, what fails usually is the rubber diaphragm in the valve. The rebuild kit has the diaphragm and orings. There is no reason to replace the body unless it is eroded.

stooperbike · Jun 22, 2011

The whole valve should be replaced, the problems will occur with mechanical part and not solenoid. But if everything is replaced all can sleep better at night. I used to run into this in my early years and it was maintenance making up stupid excuses and taking the easy way out.

OkiePC · Jun 22, 2011

Thomas said:
If these are similar to temperature control units that I have for a similar task, what fails usually is the rubber diaphragm in the valve. The rebuild kit has the diaphragm and orings. There is no reason to replace the body unless it is eroded.

Ah, yes, I forgot about the diaphragms being separate too. Those can be replaced without taking apart the plumbing, and the condition of the body can be inspected while apart.

Brian123 · Jun 22, 2011

Thomas said:
If these are similar to temperature control units that I have for a similar task, what fails usually is the rubber diaphragm in the valve. The rebuild kit has the diaphragm and orings. There is no reason to replace the body unless it is eroded.

^This

We do this when we need to do maintenance on most of our ASCO valves. Most of them are controlling natural gas or air though. If the base is in good condition, there is no need to replace it, just swap in new soft parts. Usually, we can find whole valves on eBay for less than what ASCO charges for the repair kit. So we just swap the entire top end (minus the coil) when doing maintenance and recycle the bottom end.

Brian

jnawillis · Jun 22, 2011

OkiePC said:
They are replacing only the solenoid and not the valve. It's been my experience that the solenoids are pretty reliable, so something unusual might be happening if you are seeing a large number of failures. The valves themselves are pretty reliable too, depending on the quality of the fluid they are exposed to.

I don't think it will cause any problem to only replace the solenoid, but it doesn't make sense to do that when the machine is down for scheduled preventive maintenance. That's just laziness IMHO.

Sounds right, Okie.

I worked with the same valves & equipment for the last few years & only had to replace a few ASCO solenoids the entire time. I never rebuilt the diaphragm. Only replaced the actual valve when we rebuilt the entire machine.

If the solenoids are failing often, then someone should look into it. As, Okie said, they are reliable. More than likely a short from water leakage.

Hope this helps.

RussB · Jun 22, 2011

I used to specify Asco because one could change the solenoid so easily and quickly. You are correct that there are times during a scheduled maintenance inspection where the whole valve needs to be replaced but not "as a rule" with these. Replacement parts are designed to be drop in why else would you need them. If in doubt check with your valve supplier they will be able to give you better information than we can.

leitmotif · Jun 22, 2011

Thomas said:
If these are similar to temperature control units that I have for a similar task, what fails usually is the rubber diaphragm in the valve. The rebuild kit has the diaphragm and orings. There is no reason to replace the body unless it is eroded.

I fully agree with this. The only catch on the diaphragm is the equalize / bleed hole must be properly oriented - dont remember which way - dont need to, the enclosed directions tell you. The kits also have the stem assy.

All that I have seen are a good brass body so no need to replace the body.

These are a four bolt assy.

Dan Bentler

danw · Jun 22, 2011

Tim Ganz said:
just replace the top with all the guts and leave the bottom on the machine.

Nothing prevents a valve from being installed upside down, so which part is top and which part is bottom isn't clear.

Assuming the top is the electrical coil, here's Asco's troubleshooting chart.

dploof23 · Jun 23, 2011

leitmotif said:
I fully agree with this. The only catch on the diaphragm is the equalize / bleed hole must be properly oriented - dont remember which way - dont need to, the enclosed directions tell you. The kits also have the stem assy.

All that I have seen are a good brass body so no need to replace the body.

These are a four bolt assy.

Dan Bentler

Hello,

Yes the bleed hole needs to be 45 degrees from the out on those valves. Not all of the bodies are brass, the brass ones we use are for air. We have valves that we use for natural gas that are aluminum.

On another note we have multiple pieces of equipment running here 24/7 using 100 or more of these valves and 99.9 percent of the time they are rebuilt with the diaphragm and plunger assembly, the post that the plunger rides inside and any associated o-rings. RARELY have I seen the bottom portion of the valve or the solenoid need to be replaced.

[/quote] Nothing prevents a valve from being installed upside down, so which part is top and which part is bottom isn't clear.

The top is the side with the solenoid.

Dave

wolverine1981 · Jun 24, 2011

Hello Tim

Here is a little info from asco and gould valve installation.

Asco Valves
Taken from installation and maintenance instructions.

"This valve is designed to perform properly when mounted in any position. However for optium life and performance, the solenoid should be mounted vertically and upright to reduce the possibility of foreign matter accumlating in the solenoid base sub-asstmbly area."

Gould Valves
Some good videos on installation / maintenance / troubleshooting.

http://www.gouldvalve.com/solenoid-valve-support/solenoid-valve-installation

Hane A Nice Day
Tom

rguimond · Jun 26, 2011

If frequent change-outs are necessary for whatever reason, I recommend using two valves in parallel, which are tee'd together at inlet and outlet c/w with isolation valves. Leads from each coil go to a DPDT switch mounted on a nearby electrical box. If a valve fails, you just open the isolation valves to the spare unit, flip the switch to energize it, close the isolation valves to the fualty unit and repair it.

GEORGI · Jun 26, 2011

Hi Tim.What kind of water You are using-is it distilled or something else?Do You see any particles or scales in the water?What is the temperature of the water-the higher the faster will the rubber diaphragm lose the flexibility?Whatch at the bottom part if You can see missing metal pieces-that can cause keeping the temperature too low.

BDL273 · Jun 27, 2011

Hi all I hate to semi hijack this thread but I am having a problem with a ASCO CDV valve and was wondering where you guys get your rebuild kits from? I am not having much luck on the web or ebay for that matter. Local supply shop was confused when I called and asked they said they never seen a rebuild kit for the ASCO valves. I was told though they would gladly sell me a new one! lol

OT: Asco Valves

Tim Ganz

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OkiePC

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Thomas

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stooperbike

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OkiePC

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Brian123

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jnawillis

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RussB

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leitmotif

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danw

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dploof23

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GEORGI

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