I have a honeywell rth8580wf heating thermostat. I wonder what the output of the "white" terminal is (heating control). Is it only going from 0V to 24V or is it continuous depending on the room temperature?
closed as off-topic by Voltage Spike, pipe, uint128_t, Wesley Lee, Dmitry Grigoryev Mar 20 '17 at 10:11
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Voltage Spike, pipe, uint128_t, Wesley Lee, Dmitry Grigoryev
It's a contact closure. When the thermostat wants heat, it closes a contact between the "Rb" and "W" terminals, which allows current to flow.
Here's a good reference for thermostat wiring in general.