The 4G box does not have a contactor
The 4G box does not have a contactor
Now I know why I couldn't find one. I think I've narrowed it don to the power supply. It's not easy to check because it only hums from a cold start. If I turn it off and restart it will not hum. I have to wait an undetermined amount of time for it to cool down. I'll investigate further this AM.
Phil
Before I fired up the control box I removed the power supply and blew it out with compressed air. There was some dust but not much. Put the power supply back in, turned it on, nice and quiet. Thanks to all who replied.
Phil
Follow up on noisy fan. I thought that I had resolved the problem by blowing out the dust. The noise came back. I found a fix on Youtube that appears to be working. I ws able lubricate the fan bearing. Not difficult.
https://www.youtube.com/watch?v=MH52cMQp2c4&t=402s
Phil