No Heat? No Problem: How To Diagnose Common Boiler Problems

Posted on: 2 September 2014


Do you have a hydronic heating system that refuses to put out any heat? Before you pick up the phone to call a technician, you might want to see for yourself what's causing your boiler to bail out when it comes to keeping your home nice and warm.

The following takes a look at the potential causes of a no-heat situation, as well as ways to correct them. Although you can fix many of these problems on your own, keep in mind that there are some tasks that should be left to a trained boiler specialist.

Heating Fuel Failure

Heating fuel failures range from bent oil lines, clogged strainers and oil filters to a broken fuel pump, air in the oil inlet line or a missing bypass plug, especially on boilers with two-line oil tank systems. In many cases, it's the heating fuel that's to blame for a no-heat condition. Exposure to freezing weather often causes the oil to jell or become waxy, making it harder to move through the oil lines and ignite properly.

Ignition Failure

Faulty ignition can also be the cause of an oil-fired boiler failure. Signs to look for include:

  • A weak or burned-out ignition transformer
  • Clogged burner nozzles
  • Dirty burner nozzle electrodes
  • Bad electrical grounding

You can clean the nozzles by soaking them in a kerosene bath for approximately 30 minutes, taking care to remove any residue with a cloth rag. In many cases, it's easier to replace the nozzles and ignition transformer with brand-new parts.

Motor Failure

In addition to the ignition transformer, there's also the motor that drives the oil burner. There are plenty of causes that could trigger a reset condition:

  • The motor is experiencing excess pressures or thermal loads, leading to premature failure.
  • The centrifugal motor switch could be stuck in place. Giving the motor a firm hit with a hard object may free the switch.
  • The internal windings, bearings or stator have burned out or failed.
  • Outside voltages are causing the motor to burn out prematurely.

If your oil burner motor has a reset switch, restart it by pushing the button back in. If the motor triggers the reset switch again, it's up to your technician to replace the motor.

Loose Electrical Connections

You may want to check each and every electrical connection on the boiler, making sure that all of the plugs are firmly and snugly connected. Make sure there are no exposed or frayed lines. To prevent electrical shock and serious injury, make sure the boiler is off before you look for loose connections.

Thermostat Problems

The thermostat helps users regulate the amount of heat sent throughout the home, or in the case of multiple-zone systems, through each zone or individual room.

Make sure the thermostat is properly wired into the boiler controls. If there's no wiring schematic available or if the wires are all the same color, have a trained technician take a look at the wiring.

If the thermostat uses a battery, you may have to change it. Most thermostats use AA or AAA-size alkaline batteries, which are relatively easy to purchase and replace.

Important Safety Tips

Most boilers feature a red safety switch located on the electric motor or the primary control for the burner. This ensures that the boiler stops working and remains inoperative until the condition that triggered it is resolved.

Once the problem is resolved or if you don't see anything wrong, you can reset the safety switch as directed by the manufacturer's instructions. Don't try to reset the boiler multiple times – this can cause unburned fuel to flood into the combustion chamber, resulting in a dangerous puffback explosion that could damage the boiler itself and the surrounding area.

If all else fails, don't hesitate to call on a technician to provide a professional assessment of the problem, as well as the amount of time and effort it'll take to get your boiler sorted out. Be sure to visit this go to website for more information.