Comments about Jackson Systems SPDT Building Automation Relay (RY-1-BA):
I now have two of these in service in my Cabin in remote Utah. No flaws at all. The first has bee in service 3 years operating my self designed hydronic heating system. It runs from a thermostat switching the low voltage signal while it relays to control a recirculating pump.
The second is similarly being used for a thermostatic control of a Fantech FR160 fan