What is the expected operating surface temperature of the air heater mounting plate and exhaust?
How hot does the mounting plate get? How hot does the exhaust hose get?
The following temps were gathered after 10 minutes of running heater on high with ambient temp around 60 degrees. Gasoline unit. Tempuratures may vary based on a variety of factors such as fuel type, ambient temp, manufacture date, and more.
Below image shows outskirts of heater plate mounted to plywood subfloor with 5 inch round cutout for heater. 78 degrees F.

Image below shows the temp of the metal heater mounting plate under the heater. 186 degrees F.

Image below again shows different reading from bottom of heater mounting plate 213 degrees F.

Below image shows the temp of the exhaust hose where it connects to exhaust port on bottom of heater. 483 degrees F.
