metlmnExplorerJan 23, 2014aqua hot2013 Diplomat. I have heat on zone 4, but only blows cold air in the other 3 zones. Any ideas why?
JCMSrExplorerJan 24, 2014x4 on giving the valves a good whack. Have had this happen twice over the past three years and one tap solved the problem. Will take longer to take the cover off than anything else.