Re: Remotron heater - manual request
I was not able to track any information down. I ended up removing the old controller entirely and making a new one myself. I used an Arduino microcontroller. It is probably as safe as the original control module but certainly not "failsafe". I would never run it unattended or while sleeping so I view this as an interim solution.
As to the plug - I assume you mean the spark plug for the ignitor. I just cleaned and reused the existing plug. It only sparks for a short time on start up and the quality of the spark is not particularly important to function. Any plug with similar dimensions of projection into the flamebox would be fine.
What state is yours in? Once I established that the flamebox and surrounding body were still sound I was prepared to have some fun getting it going again. If there is any doubt as to the integrity of the flamebox you should remove it - it is just too dangerous.