Visual inspection at the oil burner itself:

Looking closely at the oil burner and the furnace, boiler, or water heater (calorifier, geyser, cylinder) where the oil burner is mounted gives very important oil burner troubleshooting information, as we describe here.

This article series explains to inspect, diagnose & repair oil burners used on oil-fired heating boilers or furnaces using a visual inspection approach as well as (optional) simple test equipment.

We include a description of common oil burner adjustment and operating problems and we illustrate some of the basic oil burner tests and measurements made in servicing and adjusting the equipment for safe, efficient operation.

Signs of Trouble at the Oil Burner Itself - Visual Inspection

The oil burner inspection becomes detailed, and diagnostic, when you can actually see the equipment.

It's obvious that you should notice oil leaks, soot in the boiler or furnace room, noises, odors, signs of repeated repairs, piles of junked parts, signs of unprofessional work (covers off of controls, sloppy wiring or plumbing).

But a closer look at the boiler and the oil burner can tell us about operating problems even before the heating equipment is actually turned on.

[Click to enlarge any image]

Watch out: Do not miss these diagnostic clues as some of them also involve serious safety concerns.

• Are there signs of backpressure
  
  in the combustion chamber? The cause may be a dirty boiler or furnace, a blocked flue, inadequate draft, etc.
  
  We have seen oil burners that suffered through three or four transformer replacements, in one job every few months:
  
  the service tech had not realized that chimney problems and backpressure were causing so much heat blow-back into the oil burner tube that the transformers were being "cooked"
  
  - the clue was obvious if you knew that tarry goop leaking out of a transformer means it's overheating.
  
  Our photo of backpressure burns at an oil fired boiler (left) shows rust around the inspection port
  
  - a hot combustion chamber has burned off the paint in this area.
  
  The oil burner itself, a Beckett oil burner, was tolerating the backpressure in this case and was undamaged.
  
  But the backpressure cause (a dirty boiler) needed to be addressed.
  
  More often we see soot around the oil burner as a sign of backpressure, such as is shown in this this horizontal furnace
  
  OIL FIRED UNIT BACK-PRESSURE PHOTO.

• Are there oil leaks 
  
  at the oil burner or at the Fire-o-matic fusible link oil valve (that should be installed at the oil burner burner) or at the oil tank?
  
  See OIL SUPPLY LINE SAFETY VALVES, OSVs.
  
  Also see OIL TANK PIPING & PIPING DEFECTS.
• Is the system safely connected to a chimney?
  
  If not, stop worrying about the oil burner and shut the system down.
• Look at the temperature/pressure gauge:
  
  normal operating values? Boiler temperature and pressure are indicated on the TP gauge and should show increase not to exceed normal operating limits (200 deg F or less and less than 30 psi)
  
  If the aquastat settings controlling a hot water heating system boiler are set to unusual temperatures that may indicate an operating problem, a heat distribution problem, an un-trained service tech, or homeowner meddling.
  
  On hot water heating boilers, the pressure and temperature gauge reads about 12 psi cold, less than 30 psi hot. Over 30 psi the temperature will cause spillage at the temperature/pressure relief valve.
• Look for Typical operating temperature settings 
  
  on the oil burner primary control: LO-120-160 HI-180-200 °F.
  
  Typical operating temperature observed at the gauge will be below the high, and can be as low as nighttime room temperature in non-heating season if no tankless coil is in use.
  
  The temperature/pressure gauge may help in checking for normal conditions before and during boiler operation. However the gauge can be wrong!
  
  See GAUGES on HEATING EQUIPMENT for details
  
  Furnace temperatures on oil burner-fired warm air heating systems  are not normally measured by a gauge but are reflected on the settings of
  
  the FAN LIMIT SWITCH.
  
  Steam boilers and their oil burners in most residential installations operate at low pressure (a fraction of 1 psi) - if the steam boiler pressure switch is set high, that may indicate a heat distribution problem that has been "fixed" using an expedient but improper approach.
  
  See STEAM HEATING SYSTEMS
  
  Oil burners on water heaters 
  
  use similar (but generally simpler) high limit and low limit temperature controls but a temperature/press rue relief valve that is designed for water heater operating temperatures and pressures.
• Water leaks at valves or fittings 
  
  which drip into the jacket of a steel boiler or onto controls or zone valves or for warm air systems, plumbing leaks onto the furnace, or condensate leaks from a combination heating and air conditioning system that drip onto the heat exchanger risk failure, dangerous carbon monoxide gas hazards, and ultimately loss of heat.

Photo above: My pen points to the oil burner air bleeder valve at the right side of this two-line fuel unit installation. Look for leaks of heating oil anywhere on or around the fuel unit and the oil lines connected to it.

• Oil leaks at air bleed valves
  
   (photo above) or other fittings on the fuel unit on the oil burner.
  
  In our photo abpve at the left side of the picture my pen points to the bleeder valve used to purge air from the oil line;
  
  Look for oil drips here as well as at the oil line fittings (and look at the fittings and gaskets and connections on
  
  the OIL PUMP FUEL UNIT
• Oil burner air shutter
  
   (Photo below) debris, dirt, or shutter adjustment problems or inadequate combustion air; because there is invariably a thin oil film on these parts, building pets, especially dogs and cats, may sh
  
  ed hair that collects-on and blocks combustion air entering the oil burner.
  
  Our second photo (below) shows our pen (photo above right, at bottom center) pointing to the very small opening in the air shutter at this Beckett oil burner.
  
  You can see that even a small amount of cat hair sticking on this opening will easily block the flow of combustion air into the oil burner, thus causing improper (and sooty) oil burner operation. In this photo the opening is not blocked by debris, though we see a little soot there.

Oil Burner Won't Run: Diagnostic Steps - what to check in what order

This topic has moved to at OIL BURNER WONT RUN

Readers needing an approach to heating system inspections that assures thoroughness, should also

see HEATING SYSTEM INSPECTION PROCEDURE where we explain an organized approach to inspecting the entire heating system, beginning outdoors, continuing indoors, and ultimately in most detail in the boiler or furnace room.

This article explains the inspection, diagnosis, & repair of oil burners used in heating appliances such as hot water boilers, steam boilers, & water heaters.

In the oil burner inspection article provided here we explain visual and other clues of oil burner problems.

To find what you need quickly, if you don't want to scroll through this index you are welcome to use the page top or bottom SEARCH BOX to search InspectApedia for specific articles and information.

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Continue reading at OIL BURNER OPERATING TROUBLE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• OIL BURNER INSPECTION
• BUILDING EXTERIOR Oil Burner Trouble
• BUILDING INTERIOR Oil Burner Trouble
• OIL TANK EFFECTS on OIL BURNER
• BOILER / FURNACE ROOM TROUBLE SIGNS
• OIL BURNER VISUAL INSPECTION
• OIL BURNER OPERATING TROUBLE
• OIL BURNER INSIDE TROUBLE
• OIL BURNER CO₂ TEST
• OIL BURNER SMOKE TEST
• OIL BURNER WONT RUN - Diagnostic Steps - what to check in what order
• HEAT WON'T TURN ON

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INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING OIL, OIL BURNERS, OIL FIRED HEATERS, OIL TANKS

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