Being more stupid than usual this morning Harry. It was the over-pressure safety relief valve that was fitted upside down. This is little more than a grommet in the lid. So, entirely possible.
Read some of the reviews here.
Tim
Just picking up on this comment. I've never seen a safety valve described as a "ready to serve" indicator. In normal use, it should never pop up, or at least it should only rise slightly and seal the valve. It only responds to pressure, not time and if it has popped up, during normal use it isn't functioning properly. How does it know that the contents are cooked??
At least this is my experience. I've just looked on line at them and they are indeed called "ready to serve" indicators (but not by Prestige) which I must admit I find puzzling.
Tim
Not all Prestige models have them. But I met them in the past. They are a dual purpose device intended (a) to show users when the cooker is at pressure as well as (b) to act as a safety valve. I never really saw much point in the former purpose and have got by without it on the 2 pressure cookers I've owned in the past 40 years. But I can see that users who don't u/s how pressure cookers work might find them helpful.
Anyhow, I hope noone here wants to encourage the "don't sell spares to anyone other than authorised repairers, design it so there are no user serviceable parts, no price is too high to save the life of one extractor fan...." brigades just because of one DIY bugger-up (no criticism of the OP intended - my bugger-ups are legion).
Charm donor.
Agreed. However, for someone with basic reading skills, it should be obvious that the OP was talking about the safety release valve and not the dead weight regulation valve.
These are designed to operate as a fail safe, should the normal pressure limiting device not operate correctly, or be defeated for any reason. When they do operate, the scenario described is pretty much what would be expected.
The situation as described here suggests that the incorrect fitting meant it operated too easily, and below the normal working pressure of the cooker.
Again, the OP did not describe a steam explosion, but an unexpected venting of pressure.
Your conclusion is not supported by the the facts as reported.
Its a odd term certainly...
My (20+ year old prestige) has three "valves" in total[1], the safety valve as described. A centre mounted "pop up" indicator that shows when its up to operating pressure (this is where the weight tends to be on the current models), and then a weight valve to one side near the handle with two positions - one for cooking, and a second for venting.
Can't really imagine how any of those would be called a ready to serve indication.
[1] Lid as in the second picture here:
The logic is they help indicate when you can turn the heat down... so you keep the heat high to get the thing up to pressure, but once the pop up valve does its thing, you know you can turn it down to a simmer, just to maintain the pressure.
(having said that, you could just wait until the weight control valve starts letting by to indicate the same thing)
We had one years ago and it was "ready to serve" when the little pin dropped back down into the rubber grommet. (some considerable time after you had turned the heat off - or quicker if you had used the bath of cold water).
It didn't mean it was ready to serve as in "properly cooked" but as in "you can now take the lid off"
I was commenting about the OP's "ready to serve" indicator, although I should perhaps have said "at any pressure" rather than "at the desired pressure".
As you have I think described in your earlier post about your own cooker some Prestige models have *2* indicators as well as the weighted valve:
a. the Ready to Serve indicator pops up when the cooker is under pressure (ie *any* pressure); and then falls back when it's not - showing that the cooker is depressurised and can be opended;
b. the Rise 'N Time indicator pops up when the correct temperature (ie the *cooking* pressure) has been reached to tell the user to start timing.
If it's a nonrusting metal and the pressure ability is far enough above the working pressure, is regular inspection really necessary?
I cetainly understand why it is with locos, but they rust, run at massive pressure and are huge enough to cause multiple fatailities.
NT
Oh dear! Until now I hadn't understood why so many regulars make fun of you, or why you persist in posting so many strange links. Ho hum. A (my) pressure cooker has a safety valve and interchangeable weights; the safety valve acts as an, errrrr, safety valve and the weights allow the appropriate pressure to be set.
It is trivially easy to fit the safety valve upside-down and I now know that when this happens the pressure builds normally until but that after a while the safety valve is ejected. The resulting fountain is surprisingly powerful, wide and long-lasting. Once the instant "is he OK" concern had been dealt with I burst out laughing at the incredible mess that was being created.
Your apology will be gratefully, and gracefully, received.
Ah yes, much fun with those many years ago, that weird weighted thingy you placed over the top that went up and down a lot. Never did actually trust those things.
Brian
The function of that device is to vent air from the vessel. Unlike the Safety valve it remains open until the vessel is pressurised. A mix of air and steam is at a much lower temperature than steam alone. It closes when the air has been displaced from the vessel.
The pressure (hence temperature) in the device is adjusted by removing rings from the dead weight safety valve. Usually you have the option of 5/10/15psi They have deadweight safety valves because they are unlikely to go wrong.
They are useful for tough meats that need a lot of cooking. Also good for sterilising homemade bottled/tinned food.
Labeled indicator. It is not a safety valve, it is an air vent. It remains open until air has been cleared from the vessel. Then it closes. At this point steam pressure builds up in the vessel, free of air. Or reasonably so. So when it closes it indicates that the air is cleared and the cooking process has begun.
The deadweight safety valve is closed and remains closed until working pressure is reached. The air vent is normally open and closes once air is cleared and pressure is coming on.
It's not a "safety release valve" see previous post. There is astounding ignorance around here at times.
It's because none of them are.
If the weights become jammed down for any reason it *will* function as a pressure relief valve, which is why it has the T-bar underneath to stop it being completely expelled.
Your ignorance is quite astounding at times.
Looking forward to your apology to the OP for doubting the whole episode. Astonishing that one so learned shouldn't understand that such and event is possible.
Tim
It was ready to serve because the vessel had depressurised and could be opened. The locking ring has indents to prevent opening under pressure.
The pin on the AIR VENT dropped when pressure fell and a vacuum was pulled. The vacuum is relieved by reason of the design of the lid sealing ring.
Remembering the pressure cooker my parents had ~50 years ago (Prestige) there were two pressure valves: a weight (actually a set of three that fitted together to change the max pressure) which released steam when 'underway', and a pin in a grommet that was the safety valve. Using the safety valve to indicate 'ready to serve' seems a very bad idea.
Many pressure cookers have only the valve described and the dead weight valve. Therefore one of its functions most certainly is to operate as a failsafe.
And almost without exception, yours.
Happy new year.
Yup, mine does.
Yes, described like that in its negative sense, I can see where the "ready to serve" naming convention comes from...
Indeed - and I do time from when its popped up (as well as turning the heat down).
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