Ferret thermostats adjustable?

[LRDG]

Since you raised the issue of rad pressure caps, I have some questions.

The pressure relief valve is a semi-permanent attachment to the top of the rad. Semi-permanent in the sense it is not just the standard screw-on cap. From the manuals, its setting is 10 psi.

The Ferret I am working on also has a "rad cap" on the filler opening in the line between the t/s outlet and the top of the rad, with a spring-loaded relief on it rated at 7 psi. I've tested this cap and it lifts at 6 psi.

So was the Ferret originally fitted with a non-relieving filler cap, leaving the rad-mounted relief valve to lift at 10 psi?

If I pressure test the whole system at 10 psi to check the system integrity and confirm the RV lifts, do I run the risk of finding it won't reseat, leaving me scrambling for a spare? It seems it has a soft rubber seat seal and who knows what condition it's in. (I think I know the answer to that question.)

I guess I run the risk of lifting the RV no matter what pressure I test at.

Is there a real risk of causing the pump shaft seal to leak in an unfixable way? It's a mechanical seal, and I know they can just let go if the rotor pops away from the stator and sticks open..