DH Kiln ( Hardwood) not reading relative humidity/Compressor wont turn on

[Goby Matt]

Hello!
Can anyone help me with this issue?

I have  4 different Nyle L 200 kilns in refer containers. 3 of 4 are having an issue.
The control unit runs on RH ( Relative Humidity) love sensors and controller. 
The RH dictates whether the compressor will turn on. 
Has anyone had an issue where the control unit stops reading RH or a ooo-zero amount, despite being high humidity?
I have swapped control panels ( display screen), humidity sensors from a working unit to unit which is not working. Tested compressors, tested wiring, reprogrammed the head unit. I have come to a dead end on trouble shooting next to replacing the system completely. 

Any help would GREATLY appreciated!
Thank you

[David Freed]

Welcome to the forum. Lots of knowledge and info here at FF.

Three out of four kilns being down isn't good.

I don't have an answer, but I hope you get an answer. Let us know the answer if you get it figured out on your own.

[DR Buck]

I find it very odd that 3 out of 4 have the same problem at the same time.    I use the Wood-Mizer RH controller on my DH kiln and have had to replace both the sensor and the RH module over the last 10 years.   A lightening hit near by killed the RH module.   The sensor just stopped working though.

Is it possible you have something wired wrong in 3 of the units?   If you have tested everything individually that sounds like the only thing it could be.  If you have already swapped good parts into the non working unit and it still doesn't work you may want to try and swap the non working controllers and sensors into the working kiln to see if it keeps working.   Only swap one item at a time and then put the good one back in before swapping the next part.    You can always call Nyle and see what they can add.

[scsmith42]

Usually when my mine reads zero's on the PLC it means that it got fried from a voltage surge.  Darn little buggers aren't cheap either (about $400 bucks a pop as I recall).

My problems decreased significantly after I added a surge arrestor to the load center, but I'll still lose one every couple of years.

Call Stan at Nyle and he'll probably know what's wrong off of the top of his head.

[Southside]

If all three started to act up at the same time then look at the common factor - has to be either line voltage surge or poor grounding that did not give stray voltage a place to go.  The swapping parts and not getting a different result makes that conclusion even more possible as a voltage spike will not do the same damage every time.  I had a house that either was stuck or very closely struck by lightning years back - the insane electrical damage was all over the map from stuff that would not turn on to items that were blown off the wall and melted and a 3/4" hole in an interior wall that was right by an exterior door which was bowed out with a nice welding mark across it.