# Pressure release valve on a Pressure Pot



## PSNCO (Mar 7, 2014)

How important is the emergency pressure release valve on a pressure pot?  As I was  modifying my pressure pot, adding a valve and a plug onto the pressure gauge, the emergency pressure relief valve between the lid and the gauge unthreaded from the gauge and will not thread/tighten back in.

Am I fine to just thread the pressure gauge directly into the pot's lid and discard the pressure release valve or is it absolutely necessary to have the pressure release valve on the pot?

I'm getting tired of something that should be so simple to modify being a royal PIA!

Mark


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## Cmiles1985 (Mar 7, 2014)

I haven't found it necessary. If your compressor has a built in regulator, set it to 80 psi (or whatever you plan on pressuring up to) before connecting to your pressure pot


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## plantman (Mar 7, 2014)

There was a reason the bombs in the Boston Marathon were put in pressure cookers/pots. When sealed, they will hold the maximum pressure until they explode or the seal fails. Should something go wrong with your pressure pot or the regulator on your air compresser, I do not think you would want to be in the same room with it. Nothing is absolutely necessary. Chances are that nothing will ever happen, but there is a reason they call it an emergency releif valuve !!!  You have fire insurance, but I don't think you expect your house to burn down.  Jim  S


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## darrin1200 (Mar 7, 2014)

I would keep one attached. But if you bought a cheep pot like me, then the relief valve is probably to weak anyway. My kept going off at 30psi. I bought a new one, 115psi.  I know its a little higher than I would prefer, but as was mentioned before, this is for that unlikely situation and I'm comfortable with it.

It took me three trips out to get pieces and a bit of jb weld, before I got mine working. Now it works great and I'm glad I stuck with it.


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## jsolie (Mar 8, 2014)

I considered not using the safety valve when tweaking my HF paint pot.

The pressure relief valve decided to come apart and it was giving me a hard time to put back together in a way that would hold any pressure.

Since I don't keep the air hose connected to my pot when casting, I figured that I'd be okay without the release valve -- as long as I kept the regulators on the air compressor and the pot itself to settings that are under what the pot is rated for.

Fortunately, I did get the valve back together and it's installed on my lid.  I've got the regulator on the pot set to somewhere between 40 and 50 pounds, and the pot itself is rated for 60.


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## skiprat (Mar 8, 2014)

Why on earth would anyone want to remove a safety device??  Most of these pots are el cheapo and every penny they could save by not having one if it wasn't needed would for sure be taken by the manufacturers / sellers.:wink:

The valve is a very simple device. Just two mating surfaces ( sometimes with a rubber seal )that a spring keeps closed until the pressure on the other side is greater than the spring. 
There is normally a grub screw behind the spring. Tightening the screw increases the pressure and loosening in decreases it. Adjusting it is easy. 
Start off with it fairly loose so that it releases pressure early. Now slowly tighten it about 1/4 turn at a time until it holds the pressure rated on the pot.
If you tighten it fully and it still won't hold pressure, then clean the mating surfaces or get a new one. 

Ha ha, you could always let Darwinism take it's natural course, but just make sure it's only you around when you use it:biggrin:


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## Dick Mahany (Mar 8, 2014)

The pressure relief on my Grizzly pressure pot would always open at ~37 PSI. McMaster Carr sells valves at incremental ratings.  I bought one rated for 50PSI since that is what my pot claimed was max working pressure, but it also opens at just over 40 PSI.  

I saw a picture of a relatively small air compressor tank that failed, and it blew the door off a refrigerator next to it and looked like a bomb went off.  I personally won't run the risk of operating without one.  So now I just need to get one that opens at the correct rating.


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## PSNCO (Mar 8, 2014)

After spending 45 minutes at Menards trying to find a threading to work and coming up empty handed, I think I'm going to Harbor Freight with the 20% off coupon and buying a new pressure pot.

I'll put this one off to the side until I have time to find the right sized fittings.  I've tried looking through Grainger and McMaster Carr for a replacement release valve and haven't come up with the right search.  Anyone have a link for the release valve I'm looking for?


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## Cmiles1985 (Mar 8, 2014)

I guess I should have mentioned that my compressor is right next to the pot, and I start with the regulator closed on the pot and set at 80 psi on the compressor. Once I finish pressuring up the pot slowly, I block in all valves (except the other pressure gauge) and disconnect the air. At no point do I leave the thing alone with air connected. Having said that, if you don't work with pressure enough to know how to handle it safely, or if you intend on leaving your pressure pot connected to the air supply, do put the relief valve in place.


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## PSNCO (Mar 8, 2014)

I finally found the last pieces needed to get this together.  I couldn't find a plug to fit for what used to be the paint hose connection.  A ball valve threaded on just fine so I added a second ball valve.  I haven't found a pressure release valve yet.  I'll test things out in the morning and see if I have any leaks or if I've created a bomb.

The wife told me to wear my kevlar vest and helmet and safety glasses.  I spent numerous years in the Army playing with demolitions.  She never worried about me then.


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## mikespenturningz (Mar 10, 2014)

I purchased an adjustable one for my pot. I set the compressor for 65 lbs. I adjusted the pressure regulator until it went off. My pot now goes off when my compressor reaches 65 lbs the pressure switch goes off. I now have my compressor set to 60 lbs and all seems to work well. My pot is rated for 80 lbs and is a HF pot.


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## PSNCO (Mar 11, 2014)

So all the fittings are on.  I pressurized it and found a bad leak on one of my fitting.  Tightened that up.  Pressurized it again to 40psi.  It's dropped to 33psi in about 30 minutes.  I can't hear or feel and air out of the fittings.  I've done nothing to the lid gasket.  This was a used pressure pot.  Should I look at cleaning the gasket and some lube?  Try and tighten all the fittings or both?


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## BayouPenturner (Mar 11, 2014)

you can adjust most relief valves, I had to adjust the one on my HF pot.  be careful that thing is a bomb sitting there.  keep your distance always yo avoid being injured if something malfunctions.


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## Indiana_Parrothead (Mar 11, 2014)

Check your joints with some soapy water, also check the fittings them self. I replaced all the cheap fittings on mine right off the bat. If it is used check the rim for nicks. The gasket you can put a very thin coat is vaseline on it. 

Mike


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## lorbay (Mar 11, 2014)

PSNCO said:


> So all the fittings are on.  I pressurized it and found a bad leak on one of my fitting.  Tightened that up.  Pressurized it again to 40psi.  It's dropped to 33psi in about 30 minutes.  I can't hear or feel and air out of the fittings.  I've done nothing to the lid gasket.  This was a used pressure pot.  Should I look at cleaning the gasket and some lube?  Try and tighten all the fittings or both?



Yes clean the gasket and if it has hardend order a new one. Lube does not really do anything to it.
Lin


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