The fact that your furnace is running doesn’t necessarily mean it is safe. This is why a furnace code exists, to provide a standard that furnace heaters need to meet in order to be considered safe and effective without being inefficient.
If you aren’t a trained HVAC professional, then you likely aren’t familiar with the ins and outs of the codes for your furnace. Those codes are important to your safety. Scheduling furnace maintenance in Eden Prairie, MN means having a professional come to your home to check things out and make sure they’re up to code.