Need help installing a programmable thermostat

[beckms]

I'm trying to install a programmable thermostat to replace the ancient, nonfunctional one in our apartment. The instructions say that I should only install it for use with a 24 volt system, NOT a 120 volt system. How do I figure out what I have? I have called both the utility company and the thermostat company, and neither has been any help.

[sneezles]

My guess would be to check out the breaker box and see how many breaker the system uses. 240 would be 2 breakers and 120 would be just one. I'll ask DH when he comes in for lunch if you still need help then.

[sneezles]

OK, found this tidbit:

One way to verify that you are currently using 24 volts is to look at your old thermostat. If it is a mechanical thermostat, meaning non-digital display, simply remove the cover and look for 30 V stamped on it. If you see this, you have a low voltage system that will be compatible with a 24 volt thermostat. If you see 120 or 240 vac on your thermostat, a low voltage thermostat will not work with your system.

[beckms]

Thank you! There's a sticker inside the old thermostat that says "no more than 30 V A.C." which I assume means I'm good to go.