In the photo it looks like the heating element flange/flanges are bent, so not enough pressure is being exerted on the o ring.

This is not obvious to me but that would be a pretty good explanation of what is happening. That may have happened during my first try in which I tried torquing the bolts as much as possible to stem off the leak.

Not sure if it's worth trying to unbend the flanges though.

You could try but I suspect once their bent they will bend again very easily

I agree, that style prongs on HE can bent very easily if overtightened unevenly and I agree also that you should be able to carefully re-level them.

I removed the boiler (again) to check if the element flanges were visibly bent. I don't see any bending, but there is a slight angle between the base/flanges and the element itself. I don't think this is consequential and that it has anything to do with the leaks.

I also put the element in its hole without the gasket to see how the flanges fit on the flat bottom of the boiler. They really are quite flat, they don't wobble at all. I still tightened the bolts (without the gasket) to try and force them to be exactly as flat as the boiler bottom is. I don't see any "relaxation" or bending when I unscrew the bolts.

It is to be noted that when the gasket is in place however, and the bolt tightened by hand then 1 more turn with a wrench, there is still a visible gap between the flanges and the bottom of the boiler. I don't have any tool to measure the gap but I'd say less than a millimeter, perhaps half a millimeter to 1/32 inch, seems uniform all around. I'd have to tighten the bolts way more to squeeze the gasket until the flanges physically touch the boiler. I assume that this is by design and that the gasket alone is supposed to ensure the seal.

Another observation (I'm just trying to notice anything that could help) is that the gasket seems oh so slightly too tight for the groove in the element. It always pops out once in place unless I apply pressure with my fingers. I assumed that when squeezed by the flanges it would fall back in position naturally, but perhaps not. I took the gasket I already used before (I still have another untouched gasket) and tried stretching it wider with my fingers. Eventually I was able to make it fit the groove without it sliding out.

Stay tuned for the results when I put all of it back into the machine for my... 6th trial now. Fun fact: I can now remove the brew boiler in the Pro 700 in less than 5 minutes (starting with side panels already removed). Putting it back together is for another evening though.

Well no need for me to test this in the machine: I left the boiler full of water overnight on my bench, and it leaked all over the place. The good thing is, I can use this method to ensure everything is sealed before putting everything inside the machine.

I honestly don't see why it's leaking. That's about the simplest gasket situation and everything looks good.

There's no chance you have a bad bond between the elements and the plate they are joined to?

Does the 3 bolts fixed to the boiler flange protruding inside the boiler or there are the bulges in the internal side of the flange?
I mean, if for some reason a screw broke the flange internally, or lost the sealant, if any, maybe you can verify it.
Seems very strange that a new gasket does not seal absolutely even without pressure.

I think Giampiero's probably on to something. The bolts are welded to the inside of the boilerplate before the flat end of the boilerplate is welded to the cylindrical boiler. It seems like the only answer is that the weld of one of those bolts is bad or got a crack from the torque on it when the first gasket change occurred... Or happened from expansion and cooling, and the first gasket change wasn't even a gasket issue.

I suppose you could swap the 2 elements(with gaskets) from boiler to boiler. If the problem stays with the boiler, you know the problem in NOT the element nor gasket.

Ben Z. wrote:I honestly don't see why it's leaking. That's about the simplest gasket situation and everything looks good.

...Right?!?

Ben Z. wrote:There's no chance you have a bad bond between the elements and the plate they are joined to?

I guess that's also a possibility, but all looks good. It's hard to test; all I can say is that drops are not forming on the electrical terminals, which would be the logical place if the element weld was no longer sealed.

JRising wrote:I think Giampiero's probably on to something. The bolts are welded to the inside of the boilerplate before the flat end of the boilerplate is welded to the cylindrical boiler. It seems like the only answer is that the weld of one of those bolts is bad or got a crack from the torque on it when the first gasket change occurred... Or happened from expansion and cooling, and the first gasket change wasn't even a gasket issue.

That is a scary prospect, and at the same time something that would fit my observations (the leak always drips from the same bolt).

Given that I changed the gasket preventively (there was no leak... I was just trying to prevent a future leak like the one I had on my steam boiler, and which was fixed by a gasket change), I don't think the damage (if any) was there before I took action.

If there is damage, this got to be an unlikely sequence of event such as: no leak -> preventive gasket change -> leak because it was not well lubricated or placed -> overtightening -> damage to bolt -> leaks because of damage on all further gasket changes.

JRising wrote: I suppose you could swap the 2 elements(with gaskets) from boiler to boiler. If the problem stays with the boiler, you know the problem in NOT the element nor gasket.

This is true, but given my luck, I'm quite wary of any gasket work on my working boiler. This might be the ultimate test. But what if I used thread sealant or thread locker or even my trusty RTV silicone around the bolts to try to seal an eventual leak... Would t hat be a good idea / test? Or perhaps it wouldn't do much with pressured water trying to get out. I guess I could try to seal the hole with another method (not sure how exactly) and see if there are drops forming around the boiler bolts when it is full of water.