DC Element is 125W
AC Element is ALSO 125W ----120VAC/~115ohms/1.4A
GAS is 1040btu equivalent to 304W (Higher heat valve due to radiant heat transfer vs conduction heat transfer with elements)
AC T-stat on MAX...element should stay ON
Gas T-stat on MAX...flame should stay ON
Both AC and Gas use a 'thermocouple wire' from T-stats to fridge
Have you measured the AC Voltage AT terminal block?
Have you measured the AC Voltage from switch to t-stat?
Have you measured AC Voltage from t-stat to/thru element?
Have you measured the AC Element Resistance?
Pg 10 of this Parts List shows wiring for DC & AC Elements
https://www.gas-refrigerators.com/pdf/RM4223-parts.pdf
Gas...
Have you measured the LP System Pressure...manometer with 50% of other propane appliances on?
S/B 11"WC with fridge on gas
What does the GAS Flame look like....strong/blue and just reaching up into opening of flue?
Have you cleaned burner/orifice/flue-flue baffle?
Pg 11 of manual shows Gas Components/cleaning
https://www.bing.com/newtabredir?url...ser-Manual.pdf