If anyone wants to see what a HWS will do with the pressure relief valve plugged and the thermostat bypassed watch the Mythbusters episode. It totally destroyed the temporary building surrounding it and launched so high that it was well out of shot for most of it's ascension.
It totally surprised the crew how violent the explosion was. Quite funny to watch.

I remember that episode. Steam powered rocket.

It looks like they did this a few times. This is the most drastic, being set to launch through two sets of 8x2 floor joists.

Ok I sent the imperia chassis to a friend who specialises in this sort of vintage and the number of stuff ups was amazing. The transformer had shorted turns because of the stuff ups. The speaker fitted had a field coil of 1500 ohms instead of the required 2500 ohms, the local distance switch didnt work at all because of one of the guys mods, there was a capacitor from cathode to earth ( I think ) that was replaced by just a wire to earth creating a dead short. My friend Ron Pond rang me and explained how many things were wrong . The radio is now fully working. He also explained to me that the chassis was a badge engineered Airzone chassis for which he had all the required parts. Now I'm looking forward to getting it back.

Im thinking I might just add a 1k 5 watt wire wound resistor in series with the 1.5K field coil with the existing speaker! Will that work ok.
My question is this! With the field coil being 1K lower than it should be wouldn't the B+ be too high?

Ok guys I got the Imperia back and its working beautifully. I noticed the 2A5 has a beautiful blue dancing haze inside towards the top. I took a video of it and showed the guy who repaired it to me and he said thats perfectly fine. I have never seen that before! How awesome .

Carl, I think that was called "fluorescence"? and a product of a radiation passing through the envelope glass like a blue coloured shadow.
That was normal in a well evacuated healthy valve.
The glow that is bad is the orangey bluey mist you could see hanging around the element structure that the techs called "gassy".
That was caused by a leaky seal in the envelope and the valve is doomed............

Your 2A5 sounds like fluoresence, enjoy the light show.
Somebody with a bit more science might let us know.
Fred.

A summary of different types of glow in valves:

https://www.thetubestore.com/blue-glow

If in any doubt, you could check the various voltages and currents flowing to make sure the conditions are not outside the valve spec especially plate and screen.

Did a bit of this setting up the voltage divider in my STC830. A close watch on this is necessary otherwise the valve might be damaged, by outgassing of the screen wires I understand. Pretty easy to do, a few voltage measurements and a bit of Ohms law and other arithmetic.

STC830
having said that, the field coil in this set was 1500 ohms instead of the required 2500 ohms then the B+ voltage would have been 40% higher and would have eventually been catastrophic. I added a 1K 20 watt resistor to remedy that untill I get a proper field coil speaker.

Looking closer at this set I believe the case is not original but it still looks nice

Carl, the ohms measured in these field coils, as in any coil is ohms impedance. Not resistance.
You can’t apply E=IR in the same way.
Same as using a speaker transformer, eg replacing a 7K with a 5K, no real problem.
So in your field coil situation it probably would be fine to try at least. Just check voltages/heat if any. And use lamp in series with radio until you are happy with results.
BTW, Thanks for the bag of goodies.
JJ