Mine was installed by a complete gibbon, and I had to help him read the
instructions.

It isn't quite as bad as you make out, because its cold water you fill
it with. And that won't go BANG - just **** out of any joints. The
standard way to pressure test a steam boiler is to fill it with water
and pressurise it...for that reason..

The real danger is, if it ever boils. Thats why its equipped with safety
valves and a pipe to vent steam out of. THIS is what needs to be
thoroughly tested. A boiler of steam DOES explode, and is lethal.

Even iof you do get a 'qualified' p[lumber to instrall it, I'd suggest
reading the nstructions and cheacking up on what he does, and making
sure any recommended tests are carried out.

Agree throughout. Would the thing come with instructions on how to
test? And surely separate pressure and temp release valves would be
sufficinet here. Thats what I have today, and clearly would ensure I
had in the future!

If I can't locate Polystel, any recommendations for reasonable
cost/performance replacements? Or anyone know of anyone who'd sell
spares for Polystel ?