Contact the manufacturer for assistance. In most cases, they will just blow you off and say nothing is wrong, but on occassion a serious issue is present. Perform a search on this Forum for this topic. You will find it has been discussed in great detail.
afci's produce heat, but i never heard them hum or buzz before. most afci's, u cant install them side by side because the heat they genarate, causes nuisance trips. u have to separate them.
