Hey, guys. Ive got a YSD thats giving me fits. It has a nuisance trip and the fault is "Evap Trans/Probe sensor " problem. This thing tripped about a month ago so I changed out the Evap Chilled water prob and evap pressure transducer.
Its ran great for a month and then this weekend, it tripped again. The control panel is showing a reading of 83 psi on the evaporator with the machine off. My gauges are showing a "true" pressure of 125 psi so thats a 40 psi difference. Not good. The board is sending the correct 5vdc to the transducer and both the evap and cond transducer are sending back the appropriate 2.3 vdc that corresponds with the true pressure of 125 psi. The condenser read out on the display is correct but the evap reading is waaaay off. This is causing my trip. Initially I figured that a board change out would be necessary but after talking to york, the price is 4700. SO that made me wonder if theres a way to calibrate this reading on the board? Theres several adjustable pots on the board but none of the books I have show anything about calibrating. Maybe I need a new board but I want to make sure I make the right call for myself and the customer. Thanks for any help!