| Day & Night furnance won't come on.
We have an older Day and night furnace with a HH84AA009 or P771-7007 control board. The furnance is not coming on all of a sudden. The only thing that happens is the HFR relay clicks, nothing else. The limits switches appear to test good. The fuseable links test good(the blower would just run anyway, right). The 24 volt circuit seems to be working at least 24 volts are present from the secondary's of the transformer. So could this control board be bad? Seems like the CA3098E Schmit Trigger IC may be bad? Thoughts? Won't else would cause a no start condition? |