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Lennox two zone single HVAC system problem 续solved

RomaVacation 2025-12-07 16:50:31 ( reads)

https://bbs.wenxuecity.com/fdcj/1873948.html

Zone control board shows call signals from two thermostats. (it took us a while to realize it has that function). Zone 1 (downstairs) has air only why calling for heat. Zone 2 (upstairs work fine). 

Zone 1 thermostat should send W (heat) signal, instead, it sent G and Y (cool). No time to find out why. (room temp on display is about right). 

最后发现 zone 1 thermostat 有问题,换了就好了。$40 parts with scheduling function. I was worried about the zone control board. We jumped W to R and use that find root cause was thermostat instead of zone control board. I bought zone pump and will keep that as spare. 

zone pump has two output (pressure and vacuum ports going to two dampers: upstairs and downstairs). 

 

跟帖(3)

borisg

2025-12-07 17:03:21

Where are the two pumps

RomaVacation

2025-12-07 17:08:43

One pump (white part) only. It has two output ports.

RomaVacation

2025-12-08 08:46:56

One reddit reply thinks G and Y energized for heat pump