I was at a friends house yesterday morning looking at their HVAC issues.
They have a zoned system that has a LZP-2 control board.
I found that the zone 2 terminal is not getting voltage at the G terminal. But for some reason, it will turn on sometimes. Run for maybe 2 minutes, and then cut back out. It will also short cycle. Come on for not even a second, cut off. 10 seconds later do the same thing.
I found a loose red wire on the upstairs thermostat, but that did not fix it.
Zone 1 works perfectly fine. The fan will be commanded on as it should, and stay running like it should.
I took all the wires off of the Zone 1 terminal, and swapped zone 1 and 2. Zone 2 (now the downstairs) started to short cycle like the second floor did, and the upstairs worked fine.
So my question is, does this mean the LZP-2 controller is bad? The fan controller seems to be getting the voltage from the LZP-2, but Zone 2 seems like it has no voltage at all. Any thoughts? Let me know if you need more info, thats all I can think of right now.