Wabasto heater?

Superman engulfed in flame doesn't need heater
Google, manual.

 

It means you're f'd to the power of 15 and hope you're not someplace where it's 10 degrees outside tonight

 

When was it last serviced?
Last time a new spark plug or new fuelfilter was put in?

 

If I'm right you have 5 short and 10 long flashes. Right?
If so you have overheating fault code. could be obstruction in blower, check in tool box or where intake is for obstruction.
Next place to check, if heater equipped with air filter. It just a screen to catch dust but could be dirty.
If all this is OK the sensor could be the reason.

 

Then only one way to stay warm overnight - whiskey + women.