It gives you many of the relevant specifications on the top there, and even if you can't match it exactly, you can probably find a suitable replacement from a different company.
I don't know much about HVAC electrical, but it could very well be a fairly standard one among them and that relays sold for the purpose would be a suitable replacement. You want to determine the switching configuration (SPST, SPDT, DPDT, etc.), and then make sure you can find a matching pinout (if you can determine the switch configuration, you should be able to discern from the electronics what's the drive coil and what's the switched elements and verify that the replacement will work). Aside from that, match the specifications listed, 24V drive coil, normally open switch connection (suggests SPST to me), and at least 10A @ 120V or 5A at 240V.