Heating Repairs and Furnace Problems

Hello again!  Good Wednesday morning to everyone.  As I was writing last week’s blog I was thinking of a good story for this week and I jotted it down.  So, this week I wanted to touch on my husband’s favorite saying:  “For every good, there’s a bad”.  This holds true for the old furnaces vs. the new furnaces.  That’s what I want to blog about this week.

Well, another old saying for you:  “They don’t make ‘em like they used to”.  Applies to everything these days, heating and air conditioning equipment included.  The old furnaces, from say, 30 years ago are not the same furnaces of say, 15 years ago.  They improved some things but also made things “cheaper”, “inexpensive”.  The steel they used on the 30 years ago furnaces was much thicker, heavier, made to last.  They rusted and had to be vacuumed out but the steel was so thick on these furnaces that a crack in the heat exchanger wasn’t an issue.  As the old style, pilot-type furnaces progressed and the steel became thinner, to keep the price down, the problem of cracks in heat exchangers became a bigger issue.  And for those that don’t know:  a crack in the heat exchanger=carbon monoxide in your home.  So a crack in the heat exchanger should never be taken lightly.  To tell a story and get to my point I have to go into more detail about other issues, so I’ll get on with it.  As the new furnaces came out and they did away with pilots on furnaces and way later as they came up with what they have today:  aluminized steel heat exchangers that have 20 year warranties and are less likely to almost impossible to crack, in this regard, things have improved.  Also the furnaces are safer now, as safeties are added at almost every cycle of the new furnaces.  The new furnaces have a circuit board, what I like to call the “brain” of the furnace.  The brain gets signals from each of the parts in the start-up cycle of the furnace and if one of the parts does not “report back” to the board, or the brain that it was up and running normally, the brain shuts down the entire system.  Nope, you’re not running right now if you can’t operate properly.  It will try again 3 times for most fails and if it doesn’t start and operate correctly, the system is locked out and won’t operate.  So that’s a “in a nutshell” sort of way the furnace operates.  Give me a break if I missed something or said something wrong and you know more than me.  But anyway, back to my story.  Each safety added to the system to check it to make sure it is operating normally is another issue to go wrong and need to be replaced.  But without the safety your system could be dangerous.  The “for every good, there’s a bad” situation.  The new furnaces are safe but DO have more things to go wrong.  The two furnace parts I’d like to address after this LONG story to get to this point, are the flame rod sensor and the furnace ignitor.  Both of these parts spend their entire life in the flame of the furnace (while it is running).  This cuts down on their life span and these are the most common furnace parts that we have to replace.  An ignitor glows red hot, in the furnace sequence, when it is it’s turn to do so.  The next sequence is for the gas valve to blow raw gas across this red hot ignitor and ignite the flames of the furnace.  Then the ignitor “goes out” but continues to be in the flame as the furnace is operating.  The ignitor’s will crack and then no longer operate.  But back to the safety issue:  Say the ignitor is cracked and when the sequence is for the gas valve to dump raw gas across it, it does this but there is no “glow” to ignite this gas.  So the next thing I wanted to talk about that catches this “issue” is the flame rod sensor.  The flame rod sensor is the second most common part we change out on the new style furnace.  It sits in the last compartment of the heat exchanger and detects the heat from the furnace, then sends it’s reading back to the brain/board.  If there is no flame the board gets that signal and shuts down the system.  So raw gas will dump into the system but just for a minute and then the next safety after the brain gets the “no flame” signal from  the flame rod sensor, it’s next safety is to start the blower to dissipate the gas fumes.  So sometimes if your furnace is not working and you notice it’s just blowing cold air, now you know why!

Okay, that’s all for today.  Hope that made sense.  Have fun and have a good rest of the week!


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