The tall cylindrical Panel Ray heaters were produced in the late 1940’s to late 1950’s by the Day & Night Corporation and its licensee Marsh Corp, and was used by the manufactures of all trailer types. I picked up 5 of these over the years, and restored them for resale. While I don’t do this anymore, you can restore yours with the right materials, methods and basic technical skills. The one thing I must caution, is that the Panel-Ray uses interior air for combustion. You must open a window when you use an older heater, just as you would for a stove or oven. Modern heaters from the late 1950’s and on use air ducted from the outside for the combustion air. Using one of these is much like using your stove top to heat the trailer!
Each unit was completely disassembled, the paint stripped and sandblasted as required and then repainted with the correct bluish gray hammertone finish (available from Rustoleum in spray cans!). The LPG control valve, pilot assy and burner were disassembled & cleaned of rust and old LPG goo. Be careful of the internal diaphragms, they are the one irreplaceable component. The O-rings can be sourced at a hardware store if needed. All rust and obstructions were cleaned from the burner flue and baffle. It is best to adjust and operate the burner/valve assy on your workbench using a BBQ propane tank and regulator before putting back into the heater. Thermocouples are available at appliance parts stores. You can test yours by putting your thumb over the end of the tubing and heat the bulb with a torch. If it creates pressure, it is most likely OK. What is interesting about the 5 units I did is that each one used a different manufacture or model of control valve: General, Robertshaw & Unitrol. You might be able to find adaptable parts such as knobs, tubing and pilot assys at appliance part stores. Controls used on older hot water heaters are the closest in function and construction.