Over the past six months the hot water heater has made a high frequency whine when heating. I found that it is coming from the circuit board and more than one individual who has this model of hot water heater in the various parks I have been in have mentioned that they have the same sound. Even though I have hearing issues, it is annoying! 
I found that it is coming from the circuit board and transfers the modulation through the mounting screws and makes the sound louder.
I tried cardboard backing - did not work.
I tried rubber gaskets - did not work.
If I run it with the circuit board hanging from the wires with no mounting screws- almost unnoticeable. So I have placed a heavy bead of silicone adhesive at the top and bottom of the back of the mounting bracket and am holding it in place with tape until it dries. I am hoping that it will hold it in place during travels and not transfer the sound to the sheet metal.
What do you think?
Btw.. the funnel is because my previous pressure relief valve leaked. So I replaced it and put the funnel in place so that when it happens in the future it will weep away from the gas orifice (that I had to replace).
I found that it is coming from the circuit board and transfers the modulation through the mounting screws and makes the sound louder.
I tried cardboard backing - did not work.
I tried rubber gaskets - did not work.
If I run it with the circuit board hanging from the wires with no mounting screws- almost unnoticeable. So I have placed a heavy bead of silicone adhesive at the top and bottom of the back of the mounting bracket and am holding it in place with tape until it dries. I am hoping that it will hold it in place during travels and not transfer the sound to the sheet metal.
What do you think?
Btw.. the funnel is because my previous pressure relief valve leaked. So I replaced it and put the funnel in place so that when it happens in the future it will weep away from the gas orifice (that I had to replace).
