# help with my "new" mirro matic pressure canner



## Werforpsu (Aug 8, 2013)

I got a weighted gauge mirro matic from a neighbor who found it at a yard sale.

the gasket has been replaced and it will work perfectly (weight rocking) for 10-15 minutes. then it will start to "scream" at me. it is different then when the steam will pour out and it will not rock because the heat on the stove istoo high. 
the "screaming" is an incredibly loud whistling that my hubby could hear through the open window and out into the fruit orchard (300-400 yards away)

All the food that has been in the canner has sealed as it should, but I am confused about the reasoning behind the screaming and my biggest concern is that the canner does not have enough pressure in it which would adversly effect the safety of the food that i preserved.

ANY THOUGHTS???
Thanks in advance!
Meghan
:hair


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## BlackFeather (Jun 17, 2014)

Can you identify where the scream comes from? is it from the weight vent or another place? I'm thinking the little rubber button that blows if the pressure cooker has too much pressure might have a crack from age in it, or the pressure cooker's metal around the gasket may have a flaw that lets steam leak out. The problem is probably why it was in a garage sale. If it seems to come from the weight vent, check and see if it is coming from where the vent meets the metal lid, not from the hole the weight sits on. My vent screws into the lid of the pressure cooker, perhaps yours is leaking around the threads and needs to be tightened. Does it still jiggle while screaming?


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## Werforpsu (Aug 8, 2013)

it does sometimes do a little jiggle while screaming, and I can touch the weight and make it hiss (so it is still under pressure) and the screaming will continue while it hisses.

is there a way to tell if there is something wrong with to overpressure button?

You mentioned a flaw in the metal...every once in a while i get 1 drop of water drip off of the lid around the bottom. It seemed to be quite insignificant...could that be it? i don't see any imperfections in the metal.

The most baffling thing is that the canner will work perfectly for 10 minutes...


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## BlackFeather (Jun 17, 2014)

If it is screaming it must be leaking steam, I doubt the 1 drop of water is a sign of a problem, my guess is if it jiggles or hisses while screaming the leak must be elsewhere, like I said look closely at the over pressure button and see if any steam is leaking out, then look closely at the vent the weight sits on and see if you notice any steam from the base where it goes into the lid, mine I've notices has water bubbling there but I think mine drips down from under the weight, if it's screaming it still should be steam as it comes out. Lastly, double check the hole down the middle of the weight vent and make sure nothing is blocking it, I kind of doubt it but it could be. I'm guessing the pitch would change depending on quantity of steam, not sure but it would seem the higher the pitch the smaller the leak, or if the vent is obstructed, the larger the obstruction thus the smaller the hole through the vent. So the pitch might give a clue as to where you might look for the leak. The leak must be coming out with enough force to make the noise. Where ever the leak is it would seem that it takes 10 minutes for the steam to penetrate or the heat to expand something. Otherwise I'm out of Ideas, without me looking at it myself, and I don't think you'll want to drive within 20 miles of Niagara Falls for me to look at it.


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## Werforpsu (Aug 8, 2013)

thanks for your help.

I do notice some water bubbling around the vent. that thing is in there so tight i cant get it out....the hole though the vent is completely clear though.

i will have to get up the nerve to pressure can again and see if I can tell where it is coming from!


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## MichaelK! (Oct 22, 2010)

I'd suggest removing the gasket and carefully clean all the metal in contact with it (both pot and lid) with a green scotbright pad. Also wipe down the gasket with a soft sponge or wet cloth. You can do the same thing with the over-pressure plug.

After the canner reaches pressure, turn down the heat to the lowest setting that maintains 15 psi. Does your mirro have a pressure gauge? Mine does. I too got mine used at the flea market, I replaced the gasket, and tested it, but have not had the same problem you are describing.


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## Werforpsu (Aug 8, 2013)

MichaelK! said:


> I'd suggest removing the gasket and carefully clean all the metal in contact with it (both pot and lid) with a green scotbright pad. Also wipe down the gasket with a soft sponge or wet cloth. You can do the same thing with the over-pressure plug.
> 
> After the canner reaches pressure, turn down the heat to the lowest setting that maintains 15 psi. Does your mirro have a pressure gauge? Mine does. I too got mine used at the flea market, I replaced the gasket, and tested it, but have not had the same problem you are describing.


no i don't have a pressure gauge, only a weighted gauge.

My next step is going to be to have my hubby remove the overpressure plug (if possible) and remove the vent. i think both need a wrench to get them out. then i will put them back in and see if that helps.

assuming it is not too expensive, i guess i will look in to replacing the over pressure plug.


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## countryfied2011 (Jul 5, 2011)

I have a Mirror 21qt that my SIL gave me that she got a yard sale...only been used once before she gave it to me. It needed a new gasket so I have never used it....I order it and the overpressure plug the other day from Goodman's online...didnt cost much at all. I will be glad when it gets here because I need two canners going at once right now. I use a Presto right now.


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## Chixarecute (Nov 19, 2004)

I get the leak from my old Mirro 22 qt., too. Lisabug says to also take some vegetable oil, on you fingers, and lightly oil the gasket. This helps to "reinforce" the seal as well. Also, check the fit on the gasket. Sometimes the replacements are just a fraction small. I need to gently stretch, then oil. You can also check with your University Extension service about having it tested.


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## Werforpsu (Aug 8, 2013)

thanks for the tips.

I removed the overpressure plug and the vent and put both back in. the gasket seems plenty big enough though it is technically for a presto canner.

I will try to oil tip and see if that helps.

I think I am going to order the new overpressure plug regardless since I also need a rack for double stacking pints.

the total is about $25 (7 for the plug, 12 for the rack and 6 for shipping)..well worth it considering the canner was free.


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