Domestic fuel oil vs Jet A1
Density: 0.820–0.860 kg/l vs 0.775.0–0.840 kg/l
Burning point: +55°C vs +38 °C
Auto ignition: +255°C vs +225°C
Energy density: 36,0 MJ/l vs 34.7 MJ/L

So yes, this is what I would expect.
However the boiler might not like the higher temperatures. If it's rather old it should be good.

An interesting thread in that it shows a significant number of been there, done that [and got away with it].

A little research shows that the airframe mentioned in the media puts this 135 as a 2002 built Bundespolizei EC135T2 D-HVBM. Contrasted with the fine the whole aircraft is probably not worth much more than a million Euros as a going concern now [but it is the repair costs that they are being saddled with].

The crew were from the Fuldatal Bundespolizei base north of Kassel and the scene of the night time error was Stendal – Borstel airfield north of Stendal in Saxony-Anhalt. The airfield is around 300km [185 miles] from the Fuldatal base. I guess it is going to be a daytime open civil airfield location so the real reason for the million Euros is in the detail we may never know .... the who and how of how access to the wrong fuel was gained? They are the Federal police so they may simply have had a key [really?].

While that detail may never be known, mention has been made of other engines being fuel tolerant but does anyone have access to technical documents specific to the EC135T2 and the Turbomeca Arrius 2B2? The damage was over two sorties so probably no more that 6 hours.

If the turbines were so hot surely that would trigger a high exhaust or engine core reading or caution light to the pilots?

There may be lessons to be learned in the wider audience.

Here's some pages regarding fuel limitations on the EC135T2 I found on my computer.

I've landed in Stendal 3 or 4 times in a 44 to refuel. Massive ex Soviet Air Force Airfield, you land right next to the fuel bowser, next to the tanks, 10.000 Liters each I think. How you can NOT read the type of fuel IN THE BOWSER window, next to the ammount in liters, I have absolutely no clue. It also says the type of fuel (JetA1, Avgas 100 LL) on the big tanks on the side and front. And those guys usually fly with 2 pilots and at least 1 observer/ crew so 3 pairs of eyes who didn's see they were refueling the wrong type of fuel :ugh: TWICE :eek:

The fact that it happend at night isn't really an excuse....

"He also told me a story which came from his boss"

I don't lend much credence to 3rd hand anecdotes.

"Every so often, another boiler would go ‘boom’. On a regular basis."

On a regular basis? That really does seem unlikely. I think folks would stop doing this after the first house blew up, wouldn't they? Imagine the paperwork!

You burn oil and it heats water until it reaches set temp then the oil gets shut off. Given the stated small characteristic differences between diesel, fuel oil and Jet A1 can't see where this would all go so terribly wrong?

found this, interestig:Have you moved into a house and wondered what type of heating oil you are supposed to put in the tank? Luckily the answer is relatively straightforward. You usually have a choice between two products: Kerosene or Gas Oil.

Kerosene

The number of different names for Kerosene means often times it can be confusing trying to figure out the exact oil type you need. Kerosene for example is also known as Jet A1 Kero, Standard Kero, 28 second oil and more generically, just “Home Heating Oil”. The vast majority of modern home heating systems use Kerosene to fire their oil boiler.Kerosene is the most popular form of domestic heating oil in Northern Ireland, being widely used in oil-fired boilers and cookers. Here at emooil.com, we provide competitive kerosene prices for you to take advantage of. Our easy to use and accurate instant quote system (see top left of this page) allows you to view our Kerosene prices for delivery direct to your home. Simply select your preferred delivery option and complete the online secure checkout process.

Gas Oil

Some households and commercial customers use Gas Oil to heat their homes, their business and also for non-road vehicles. This is why emooil.com sells gas oil as an alternative home heating fuel. In Northern Ireland it gets dyed red to differentiate it from Diesel, it is also known as Red Diesel, 35 second oil and MGO (Marked Gas Oil). Please note that we do not do through house deliveries.

likely because of the parafin in the diesel yes?