So,
Interesting about the short. Was it when you first fired up the stove or was it in the system somewhere else? Is there a possibility that you have accidently compromised or damaged the thermostat wiring(thus the short)? As well and no doubt you knew this, but it was extremely important to ensure that the thermostat and the heater were connected, before firing it up for the first time.
From the factory, the stainless corrugated exhaust line should be 22 mm in diameter and 1 meter long. The air intake line I have is 22 mm in diameter and also 1 meter long and is made of a corrugated plastic, something like a dishwasher drain or shop vac hose. Not the toughest stuff in the world but I would have though it would have been OK in a well secured run under your trailer. Any deviation (L and D) from these specs are going to cause problems. I know that the 60 mm hot air corrugated pipe is a bit funky with a paper/cardboard like exterior over a flexible aluminum core but I didn't see any cardboard in the smaller combustion pipes.
Does the intake endcap have the Propex stamp of approval? As far as the WC goes, I haven't had any issue using the North American standard 11", as I didn't have the adjustable regulator. That being said, I am gearing up for a new build and I will be using an outside install (HS2211) and I will utilize an adjustable low pressure regulator....
