Ferroli Boiler repair. Ferroli Optimax he plus 31c diverter valve fixed. 109 Comments / Uncategorized / By daveadmin https://youtube.com/watch?v=cHm1Jnen3-Q I replaced the diverter valve on this boiler. This is a job in Portsmouth. I done a few days down there last week. I have some blog type stuff from when I was down there.