Which brand of PC please? Makes a big difference. And what weight are you using.

Was the water in the canner still clear? If you get siphoning out of the jars a piece of food can temporarily block the exhaust vent.

Dave

I've had that to happen on my Mirro. I stopped everything, cooled everything, and started over. Checking the vent for any blockages, and the seal. started it back up and worked ok. Must have been something between the vent (I didn't see anything) and the seal, but it worked after tearing the PC apart and starting over.

Marla

Marla, I don't know what kind of stove you have, but I was using my vintage Mirros (weighted gauge) on an electric coil element stove many years until moving over winter. If the canner wasn't perfectly level, I would have issues with the weight hanging up. I kept a small carpenters level in my canning supplies and checked for level before I began for the day, putting pennies under the burner ring if necessary, and didn't move or shift that canner till I was done in the evening. I did buy a canning element for the stove and that helped immensely.

I've got the same canners, different stove in my new-to-me kitchen and now I'll really need to get creative, I have a glass topped Jenn Air downdraft range that I never would have bought but it's here, and fairly new. My SIL puts her big All American on hers, but I've got a gas crab cooker that I've used for a second canner and that will likely be my canning main heat source for a while. On a leveled outside surface of course.

Wish we'd hear back from Maribeth, maybe we could help...