Two Trane 90XL installed 2000 run off one thermostat. One runs great now. Second furnace blows cold air and burners have no flame.
First service tech said problem was drain tube loose and pressure set too high.
Adjusted pressure and cleaned drain tube and reservoir. Same thing happened again in 3 days.
Second tech says that the main board is shot because the 4 light pulses indicate the high limit switch is malfunctioning. He jumped the high limit and the furnace started normally then quit.
He says the board is shot and needs replaced.
Can any one confirm his diagnosis?
First service tech said problem was drain tube loose and pressure set too high.
Adjusted pressure and cleaned drain tube and reservoir. Same thing happened again in 3 days.
Second tech says that the main board is shot because the 4 light pulses indicate the high limit switch is malfunctioning. He jumped the high limit and the furnace started normally then quit.
He says the board is shot and needs replaced.
Can any one confirm his diagnosis?