Multi Stage Automatic Gas Valve - Trane ACONT900AC43UA Service Manual

Reference Materials
Three-Stage Gas Furnaces

Multi Stage Automatic Gas Valve

The gas furnace manifold gas pressure is modulated
in steps by the pressure difference of the positive inlet
burner air pressure and the negative outlet air pressure
of the recuperative cell. These two pressures are
connected to the gas valve. These two pressures are
used to set the gas valve's pressure regulator for the
correct operating pressure for the stage of operation
being called for by the furnace IFC.
Note: Gas valve adjustment and manifold pressure settings on these model furnaces will be the same for both
Natural Gas and LP. The only change to the furnace for operation to LP will be burner orifices (#56 for LP & #45
for Natural Gas). Refer to instructions for more detailed information.
R - C 9