I have 58UHV HVAC. I just started using it this season and within an hour the "blocked vent safeguard switch" shut it off. I push a button on the switch to turn it back on and the furnace works for another hour, then the switch shuts it off again. I can say by touching a flue collar that it's hot, I mean real hot, almost like an iron on a low setting. I am not sure if this is the way it's supposed to be or if it means that I have a clogged vent.
What should my next steps be? If the vent is clogged then how do you attempt to clean it? Do you have to actually detach the vent pipe from the flue collar or would it make sense to climb on the roof and see if the vent is clogged up there?
Or would it make sense just to replace a safeguard switch and see if it goes off or not? How hot should the flue collar be under normal circumstances?
A qualified technician looked at my furnace last year and also they cleaned the ducts. I am not sure though if that included cleaning the vent, now I doubt it. Even if I call them again I want to find out first what they SHOULD do to fix it permanently.
Because last time the same thing happened but only once and all that young guy did was push the same button on the same safeguard switch (that's how I learned this trick). And that was enough to keep it running till the end of the season. Not this time though.