I have a 1.5 year old keeprite C9MVX060F12A1 model, dual speed DC Motor forced air natural gas. Every hour or so it has been emitting a high pitched beep that lasts for about 30 seconds. From what I can tell it is coming from within the furnace. The view window is emitting heart beat light (manual says this means everything is running fine). What does this high pitched beep mean? I would like to stop it because it is getting very annoying at night, but unsure if it's signalling a problem?