Regular Guest
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!
Professional Member
How about when the machine is running? Does the evap pressure on the display come more into line with "actual" pressure? Sometimes the display will show "xxxx" instead of a pressure when the transducer is out of range. I think when the chiller is not running your evap transducer may be out of range.
Single line panel or Optiview?
Regular Guest
Originally Posted by KnewYork
Its a Single line panel............. It comes closer together but still is around 20 psi difference in reading and actual pressure. I think when its above 140 psi is when it shows out of range or when the transducer is disconnected all together. I'm going back in the morning to investigate further before I spend 4700 dollars. The only problem is, when I reset it today, it didnt run long enough before it tripped again on the same fault. This error occurs when LCWT minus saturation temp is below -2.5 or above 25 degrees. The board bypasses this for 10 minutes. Tomorrow I am going to make sure to recheck my LCW temp minus my evap saturation temp around the 8 minute mark. Last month when this problem first showed up I think my transducer being so off was causing it to be below -2.5. Thanks for your help and any continued help you can give.
Professional Member
O.K., let's talk about part numbers and refrigerant. On page 29 of Form 160.49-M2 it shows that the nominal voltage of the evap transducer (P/N 025-28678-002) at 125 PSIG should be 4.5 VDC. This is assuming that you are using R-22 and have water (not brine) in the machine.
The 2.3 VDC you mention corresponds exactly with 83.75 PSIG. Any chance you don't have the proper transducer in there? If you used a -001 transducer (condenser) instead of a -002 transducer (evaporator) I think you would get the results you are seeing.
The board is NOT the problem. It just does math calculations with the voltages that are inputted to it.
Professional Member
had this same thing happen on 2 york millinium one 450 ather 600 one brand new out of box bad the ather had a loose wire some time would ground causing bad reading took me awhile to find it but the manufacter said replace the board 5500 iam glad i did not that would have been hard to explain . start the cheaper route.easer to explain,
Regular Guest
Ahh......This is the problem. The transducer is the same exact one thats on the condenser side. Its a 0-300psi transducer. It was new in the box inside the starter and I thought since it was a 0-300psi transducer that it would work. Thank you so much for your help.
Regular Guest
Thats wrong labeling is common.
Professional Member
It wasn't labeled incorrectly. He used the wrong transducer.
What are you trying to do get your post count up so you can turn pro? Geez.
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