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A Guide to Troubleshooting Common Issues
Finding yourself in a situation where your furnace isn’t functioning
on a cold morning can be distressing.
However, understanding a TC furnace’s typical components and
operation can help identify the problem.
An explanation of a typical TC furnace’s components and operation
may help you find the culprit.
Starting with the thermostat – ensure the temperature setting is above the current temperature of the truck camper.
Before delving into the furnace, confirm that you have power, especially connected to onshore power. You can check this by looking for a display on your microwave.
Next, open the furnace access panel. Within the panel, locate the control board and check for a green power light on the control board. This light signifies the presence of 12 volts of power.
Key Components
Dinosaur Electronics Universal Ignitor Board with Fan Control
This component is crucial for the ignition and operation of the furnace.
Atwood Sail Switch
The sail switch ensures the fan is running before igniting the furnace.
Atwood Limit Switch
This switch prevents the furnace from overheating by shutting it
down if the temperature gets too high
Operational Sequence
When the furnace functions correctly, the fan should operate for 15 to 20 seconds to purge the combustion chamber of
any remaining gas fumes.
A clicking sound indicates that the control board is attempting to open the gas solenoid valve, allowing propane to flow. If you smell propane, this suggests that the control board, sail switch, or high limit switch are likely not the source of the problem.
By following this systematic approach to understanding and troubleshooting the components of your TC furnace, you can more accurately identify and resolve issues, ensuring your camper remains warm and comfortable.
On the control board is also a RED error light with only four possible
fault indicators to help you diagnose a problem:
SteadyREDlight = internal control board failure
1 (One) flashing RED light with a 3-second pause = high limit switch or sail switch failure
2 (Two) flashing RED light with a 3-second pause = flame sense fault
3 (Three) flashing RED lights with a 3-second pause = ignition lockout fault
The flashing RED light comes with a three-second pause that is relatively straightforward and should help you count the number of flashes.
Explanation time
12 Volts from the control board go to the sail switch
(this switch senses if the electrical power is too low to run
the fan at the correct speed to support combustion).
Then to the high-temperature limit switch
(the limit switch is usually closed and designed
to “snap-open” when the furnace experiences an
over-temperature condition).
If you hear a clicking sound, the gas solenoid valve opens,
and you smell propane, the problem is most likely in the combustion chamber.
Next, inspect the components that make up the combustion chamber.
Turn off the propane. Remove the furnace exhaust pipe.
Depending upon the bass fitting connection,
you may need TWO wrenches to disconnect
the gas line from the gas valve.
Disconnect the two electrical wires that feed the valve.
One wire is the power to the gas solenoid (AKA gas valve),
and the other is ground. The thick black wire is for the
electrode and can be disconnected at the control board.
TIP – When reinstalling the gas solenoid, connect the gas line fitting a couple of turns before securing the burner screen unit.
Next, the gas solenoid, the burner, and the electrode (secured by three screws) can be removed as one unit by pulling the unit out towards you.
Burner Compatible with Atwood furnace
TIP – When reinstalling the gas solenoid, connect the gas line fitting a couple of turns before securing the burner screen unit.
Next, the gas solenoid, the burner, and electrode (secured by three screws) can be removed as one unit by pulling the unit out towards you.
Check the serviceable condition of the burner screen for rips or torn areas and is free from carbon build-up. Ensure a 1/8″ separation between the burner and the electrode. Plus a 1/8″ separation between the positive and negative posts of the electrode. If either clearance is incorrect, carefully bend the electrode post(s) to obtain the 1/8″ clearance.
TIP – When reinstalling the gas solenoid, connect the gas line fitting a couple of turns before securing the burner screen unit.
Replace all questionable parts as you seem fit.
Keep in mind that when ordering replacement parts, you need the part number of your furnace to ensure proper part replacement.
Note: The parts shown above may not match your furnace 100% – original parts and any replacement parts may differ in appearance. However, the furnace’s operation description and the related parts are very similar to those in your furnace.