The question says it all - I have a 4,200 sqft house with two water heaters - one on the far side of the house in the garage and the other in a small closet by the master suite. The latter is at least a decade older.
I have no idea how they're set up. They could be in a sequence, series, or maybe even one does part of the house and the other does the rest. Is there a way to determine this as a layperson with virtually no home repair knowledge?