The burning of a spark transformer...

The heat and hot water has been regularly quitting on me this winter.  The first few times it happened, I found out the hard way, after stepping into a spray of ice cold water.  I learned to check my heated towel rack (yes - so spoiled, I know) before attempting to take a shower.  If the heated towel rack was cold, a shower was inadvisable until the heat and hot water had been restored to full functionality.

When I returned from Prague, the heat and hot water were not functioning.  It was fixed the next day.  Three days later, it was out again and later that afternoon, I was cc'ed on the following email sent by the repairman:

Dear Hosing

Kindly contact the L.L. of the residence to replace the rusty and leaky boiler pipes, as it is leaking over the burner which almost caused the burning of the spark transformer.

Thank you

Of course, this email immediately led me to a spiral of panic:

What is a spark transformer?  And could the burning of said spark transformer lead to a fire?  How long would it take for the fire to spread so that it was noticable to an outside observer?  Would there be time to stop it before it spread to my house?  What if it happened at night?  How would I escape my house if it caught on fire when all my windows have steel bars on them and my door is really far away?  What if the spark transformer fire reached the heating oil drums and they exploded?  What if they exploded while I was home?

Technicians came and supposedly they came and replaced the rusty and leaky boiler pipes.  However, the heat and hot water have gone out twice since then, leading me to suspect they just painted over the rust and duct taped the holes or something similarly sinister, leaving me vulnerable to the dangers of the spark transformer...