First of all I am not the on who is spreading scare stories here. and rules every thing to be tossed. Neither do I. But then I don't accept the "do whatever you want, everything's fine" attitude either and I, for one, will take issue with it every time. Second: I said foaming occurs in pressure cooker(when cooking meats ..). But then immediately I added that this should not happen in Canner. So since this post isn't about cooking meats and there is no concerns with foaming it isn't relevant to the issue. Why post it? How does that help? When someone is trying to learn pressure canning and already worried the last thing they need is someone dragging their focus off on an unrelated tangent. Third: I was talking about the principles of weight system and manufacturing tolerances in general. I did not talk about the specifics as how EXACTLY they are machined. It is up to the manufacturer. And there could be variations from one to the next. Vent pipe diameters aren't relevant unless they are plugged...""" is absolutely incorrect. The combination of the hole diameter and the amount of weight determines the amount of pressure held inside the cooker/canner. So if the hole diameter also has a tolerance as well. And any deviation from the nominal can make a difference. Yes that's all well and good info for the mechanical engineer that designs the equipment and oversees its manufacturer. It has no relevance to the person using the canner at home. Milling to tolerances isn't our problem. We aren't going to dig out our calipers and mic the ID and OD of the steam vent and adjust it accordingly. So the info is of no practical use to us and only confuses the issues under discussion. Dave

The auto fill valve should be isolated and cut off from the system after the system has been filled to the correct pressure level to maintain a âÂÂclosed systemâÂÂ. Likewise the expansion tank should be inflated to its correct value before being connected to the system. Is this 40psi reading with the boiler stone cold or hot, with the circulator running or not? Has the circulator been recently replaced or operation modified? I think you have to isolate the auto fill valve from the system anyway to determine on which side of that auto fill valve the high pressure is coming from. It seems like you may have full water line pressure from the city in your system. How many floors is the building (how many feet high)? When you say, âÂÂfrozen boiler pressure relief valveâÂÂ, do you mean frozen or seized? Does the system have some sort of auto air elimination vent? SR

The spring or the clip that holds the spring, that holds the pressure foot down has probably broken. This is a job for a repairman, but it shouldn't cost much to repair.

What did you oil? The presser foot or the machine? Try oiling the machine at all the places it needs to be oiled and run a blow dryer on it. If the machine hasn't been used in a long time and hasn't been oiled, things can tighten up. Or did it work last week and it just started? Then a gear or something else could have broke. Is it a newer machine or an old one? Cheap or expensive. If it's old or expensive, it's worth fixing. New and cheap, it's a throw away.