Gasoline fired heating and ignitor issues

Gary McCreadie is an HVAC tech, the creator of hvacknowitall.com and the HVAC Know It All Podcast

This brief podcast additionally covers this burner restore intimately

The Drawback

This heating tip was generated from some on web site aggravation whereas repairing a burner.  Through the preliminary preventative upkeep, it was found that the first stage burner of the York RTU was having intermittent issues sensing flame and interesting most important hearth.  The RTU makes use of direct spark ignition, the spark is generated, the pilot valve inside the gasoline valve opens and gasoline flows throughout a pilot tube.  The flame sensor is mounted on the reverse finish of the tube, because the pilot flame strikes throughout the tube and comes into contact with the flame sensor, flame rectification happen proving the flame.  At this level, the ignition management sends a sign to the gasoline valve which engages most important hearth.  That is the way it’s alleged to work in idea, however not all the time the case.  My expertise with these burners converse to me on this specific scenario, I’ve seen this concern many instances earlier than. 

To study extra about flame rectification try this text. 

The pilot tube can grow to be blocked and corroded which may actually prohibit correct gasoline distribution, if the flame sensor can’t sense flame, the principle burner won’t ever hearth.  A faulty pilot tube can and can trigger burner points.  The RTU is liable for heating the north east nook of a vital surroundings, (pharma warehouse) the warehouse is outfitted with sensors and the merchandise saved within the facility will be put into jeopardy from temperature swings. 

The Restore

The burner was eliminated together with the pilot tube, flame sensor, spark ignitor, roll out change and the ignition module which had been all changed.  I’d personally by no means pull the burner and substitute the pilot tube with out changing the flame sensor and ignitor.  I’ve preached this previously, anytime I carry out a heating restore, I all the time substitute the roll out change.  A roll out change will be internally defective, however when checked with a meter, seems to be be to high-quality on the floor.  I’ve come throughout many conditions like this the place the burner wouldn’t hearth, the roll out which seems to be okay, is bypassed with a jumper and the burner fires.  I additionally changed the ignition management as an affordable insurance coverage to maximise an issue free heating season because of the vital nature of the surroundings.  The price of a failure will be nice, quarantined merchandise, high quality assurance investigation and lots of emails backwards and forwards together with bodily paperwork. 

After the restore and upon testing, a spark was not being generated, the issue was traced again to the brand new spark ignitor, which had separated inside the warmth shrink.  A second new ignitor was then put in, though an issue nonetheless existed.   A weaker than regular spark could possibly be heard coming from the ignitor, I pulled the ignitor meeting from the burner bracket and carried out a check.  In case you take the ignitor meeting and maintain it with an insulated set of pliers and maintain the rod near a floor supply, you’ll be able to watch it spark.  The check was carried out and the spark was robust, the following check revealed the issue.  I tilted the meeting barely, shifting the nook in the direction of floor, a small weak spark was visibly observed.  This could not occur because the ignition rod is totally insulated in a ceramic case.  Resulting from this leak, when the ignitor meeting was mounted, the spark dissipated and was not concentrated and robust sufficient to gentle the pilot.  As a check, I used electrical tape and wrapped the ignitor bracket (insulated it), it was re-installed and immediately upon testing the spark was stronger audibly talking and the pilot and most important burner fired on each try. 

You may watch all the restore on this video

Gary McCreadie

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