Coleman-Mach 48000 Elect-A-Heat is not a furnace
The Coleman-Mach 48000 AC owner manual describes optional Elect-A-Heat as a chill chaser for air that is only a few degrees too cool, not a furnace substitute, and says the heating coil normally should not be expected to glow.
Owner-safe checklist
- Confirm the ceiling assembly is actually a Heat/Cool model with Elect-A-Heat before expecting heat from LOW HEAT.
- Use the RV furnace or another approved heat source when the coach needs more than a small temperature bump.
- Do not treat a heating coil that does not glow as a failure by itself; the manual says it normally will not turn red.
- Call qualified RV HVAC service if heat mode is selected on an equipped unit but no warm air ever appears.