How can I test the Trane XV90 gas furnace? (2023 Update)

I have a company that does my HVAC maintenance. I have 2 Trane Heatpumps, and an XV90 propane gas furnace. After the last service, the tech said the XV90 gas burners needed replaced, along with a flame sensor. Total $1,100 ! He showed them to me, and I agree that they maybe have one more season left on them. After he left, I opened the XV90 doors and took a look. The burners and flame sensor were both behind one cover (4 screws) and they just lift out. I ordered the parts - total $95, and installed the 3 burners plus the sensor. Total time - about 30 minutes. There is no way to install these things incorrectly, they only go in one way. HOWEVER - I don't know how to make the furnace come on to check that all is ok. The way the system was explained when installed, 10 years ago, was that the heat pump will provide the heat until the ambient temperature outside is below 32 degrees F. Since it isn't nearly that cold here in Northern Va., yet. how can I make the furnace ignite? (The second heat pump is for the second floor, and has no gas backup).

In order to force your Trane XV90 gas furnace to come on, you can override the heat pump by setting your thermostat to "emergency heat" or "auxiliary heat" mode. This mode will bypass the heat pump and allow the furnace to provide heat to your home. If you are unsure how to do this, consult the owner's manual for your thermostat. If you still can't get the furnace to come on, it's best to call a professional HVAC technician for assistance, as there may be other underlying issues that need to be addressed.

To test the Trane XV90 gas furnace, you will need to perform the following steps:

Turn off power to the furnace: Make sure that you turn off the power to the furnace either by switching off the breaker or by removing the fuse.
Locate the thermostat: Find the thermostat that controls the furnace, and make sure that it is set to "Heat". If the thermostat is not set to "Heat", then the furnace will not ignite.
Check the air filter: Make sure that the air filter is clean and in place. If the air filter is dirty, it can cause the furnace to not work properly.
Check the gas supply: Make sure that the gas supply to the furnace is turned on and that there are no leaks in the gas line.
Turn the power back on: Turn the power back on to the furnace either by switching the breaker back on or by replacing the fuse.
Adjust the thermostat: Adjust the thermostat to a temperature higher than the room temperature, and wait for the furnace to ignite.
Observe the furnace: Observe the furnace to make sure that the burners ignite and that the furnace is functioning properly. If the furnace does not ignite, then you may have an issue with the gas supply or the thermostat.

If you are not comfortable with performing these steps, it is recommended to call a professional HVAC technician to diagnose and repair the issue.