I needed to replace my old doorbell chime. I purchased a new, simple
chime, that merely said "low voltage" (e.g. wired, not wireless) on the
outside of the box. My door bell transformer puts out about 22 volts.
(It's probably supposed to be 24). The instructions to the new unit,
which has the name "Zenith" (probably under license by the Zenith
company to Home Depot) says that it runs on just 16 volts.

The unit has two solenoids, one for the front door, and another that has
the second tone blocked for the back door. Would 22 volts be too much
for the unit? I'm not going to be replacing the transformer on the
breaker box, so my options are to use the unit as is, return the unit
for something else or calculate what size resistor to put in series so
that the voltage received by the chime is 16 volts.

Does anybody have any experience with door bell voltage? Is it
important to have the exact voltage?