Hmmmmmmmmmm

Maybe something loose. Take the cover off and check.

Could be dirty or pitted contacts. Clean and blow out with compressed air. If that doesn't help the relays are probably bad. You may be able to rebuild it but it's usually easier to replace it.

Hmmmmmmmmmm

Do you have a module to convert the relay signal to DC?
Fairly common on new relays.

the unit’s DC coiled relay prevents AC “chatter” noise and drop-out in low-voltage conditions.

Lucky me, the switch is in an easily reachable place. Will open it up next time off shore power & have a look. Could be as simple as a loose screw inside I hope.

Not sure if I even need it as I have a 2000w PSW inverter/charger on the house side of the TS.

Mine started humming.Did it for a couple of months and then no power transfer from the genny. A new transfer switch cured the humming and the no power transfer.

Ours does that - after a power outage - when switching from shorepower to the generator and back. We shut the circuit breaker on the post off - then back on and in most cases the humming stops.

Mine hummed when I accidentally hooked my trailer up to 240 volt outlet. Stroy here. It has hummed ever since. I have even taken it apart and it still hums.

Maybe it doesn't know the words... 8^) ST

There are two kinds of transfer switches (Actually more but we will only discuss 2 here)

Mine, The solenoids are "Double throw break before make" if there is no power. then shore power is selected, IF the generator is NOT running, the solenoids are in their resting state (Shore power) so there is no hummmmmmmmmmmmmmmmmmmmmmmmmmmmm.

Some have two sets of single throw solenoids with mutual lock out. When power is applied, either the SHORE or the GENERATOR (optional 3 rd set, Inverter) pull in and since these are AC operated electromagnets.. they HUMMMMMMMMMMMMMM


Now if you do not like that answer try this one: It does not know the words.