Boiler Troubleshooting, A Guide To Home Heating Boiler Repair


With our boiler troubleshooting guide, you can fix it yourself and save a lot of money. The average repair call will cost well over $100. With a little help, you can do it yourself and keep your hard earned money.


**NOTE** Only you can assess your ability to perform this task. This is a guide and cannot provide all of the details for every situation.


Proper maintenance will help you to avoid many of the common causes of boiler malfunction. Before you start troubleshooting, make sure you have performed the suggested maintenance. We will begin our boiler troubleshooting with the common gas fired heating boiler. This guide is for modern units that do not have a pilot flame burning constantly. If your unit has a standing pilot light, you should check to make sure it is lit. Then, you can use the rest of the guide but skip the part about the pilot lighting.

Gas Heating Boiler Troubleshooting


Combi Boiler Troubleshooting


We continue boiler troubleshooting with a look at combi boiler repair. We will check the unit in the central heating mode. You should begin by pushing the reset button on the unit. If the unit does not start then check the thermostat setting. If the setting is above the room temperature, check to see if the circulator is running. If it is not, check the fuse or circuit breaker for the unit. If you have power to the unit and it still does not operate, the problem could be with the thermostat, the circulator motor, or the units' control board. If the circulator starts, you can feel the unit's heating water outlet pipe to see if it is hot. If it is not hot, check that the unit's flue fan starts. If the fan does not start, the problem could be the water flow switch, the heating temperature sensor, flue fan motor, or the unit's control board. If the fan starts but the unit then locks out, the problem may be the flue temperature sensor. If the flue fan starts, does the burner ignite after a short delay? You should be able to hear the spark generator and the burner ignite. If it does not, the problem could be the spark generator, the gas valve, or the unit's control board. If the burner ignites, does it continue to operate? If it does not, the problem can be the flame sensor or the control board. In the dhw mode, the boiler troubleshooting procedure should be the same if water is being taken from the tap.


(NOTE: Most units have a minimum rate for the flow of water being taken from the tap, before the unit will operate. If the flow is not high enough the unit will not run.)