My first Truck Mount was a slide in with a propane heater. Worked fine for years. The main problem was running out of propane with 10 sq ft left to do.
After several years, I am working in the house, set the wand down to move some furniture, I hear POW!! from the truck. I go out there, and a huge cloud of steam coming from the machine.
The flow valve had died and the burner had kept on while I set the wand down. Blew the hose off the outlet of the burner.
I put on a new hose and finished with cold water. Could have ruined someones day if they were standing in front of the machine when it went off.
About a year later, the same thing happened, but the pressure ruined the Cat pump when it blew- which must have been the weakest point when the pressure of the steam got too high.
Not too much longer, I had a chance to buy an Astro brand new, had a Ballweber unit with a HX in it. No propane. Hey, I like this idea.
OK, so the heat is not as high as with the propane burner, but easy to compensate with agitation or chemicals.
No more running out of propane with 10 sq ft to do. No more steam explosions.
Gary