Aware this is a well documented topic and I've read the posts that resulted from a search of the topic. I may not have found them all.

What I did not see is whether the boiler's p-stat port tube has ever been extended by anyone to get the inlet ABOVE the boiler's maximum fill level. By my measurements, the inlet port for the p-stat tube will ALWAYS be below the boiler water line because the tube only extends approx 13 cm into the boiler, just about where the water might just be visible in the sight glass. If the tube were extended to reach the volume above the maximum water level then the p-stat diaphragm would not be exposed to water constantly.

Perhaps reducing the size of the inlet port would be required since the pressure fluctuations from steaming would not be dampened. Could this cause 'chattering" of the p-stat? Which wouldn't be good for the contacts of the p-stat. But, if you don't steam, then that isn't an issue. A small orifice might dampen the pressure change rate sufficiently.

I'm rehabbing an old (2006) yet brand new (never been out of its factory box) Elektra Semi and since I had it apart for cleaning the boiler and group and having read the p-stat failure stories I thought I'd ask. The semi required to be cleaned just like the T1 I acquired at the same time, but not nearly as bad. Both machines have been sitting in a W&S storeroom for years. Both boilers had their interiors coated with a black slimy substance (assume its a mold or algae of some sort). The T1 cleaned up real well using a citric acid bath, but I want to be careful to not damage the semi's plating so I'm proceeding with an abundance of caution.

Since there are a number of Semi owners active on the board, I thought there might be some thoughts on the topic. Just wondering if there is a potential solution to the problem.