Troubleshooting a Hydronic Heating System

A hydronic heating system.

If your hydronic heating system is faulty, there are some troubleshooting measures you can take. Hydronic heating systems are highly energy efficient and are based on either baseboard or convection units. They have many advantages over other types of home heating. They are very quiet, unlike furnace heating, and they have excellent room temperature control. However, like most things, they have their disadvantages too.


Hyrdonic heating systems are exceptionally reliable. However, like with all automatic systems, components or parts will inevitably break down at some point. Regular servicing of your heating system will increase its lifespan and reliability.

If your hydronic heating system has failed, the best advice is to call a registered engineer. However, some troubleshooting and self repair can be undertaken by the homeowner.

Does the Boiler Have Power?

If your heating system has been particularly sluggish this winter you may find that there are areas that are not operating within regular parameters. If there is no sign of power from the boiler, first check the fuses and the breaker box in your home. You may have simply tripped a breaker switch. It may be a case of resetting the breaker switch or replacing a blown fuse.

Has There Been a Pilot Light or Burner Ignition Failure?

If there is no pilot light visible then you can simply reignite using the ignition system. Most boiler systems have an electronic ignition but older boilers will have what is known as a ‘standing pilot’ which means that even if you are not using your heating system, your pilot light will always remain on but technically not active until you switch on the water or the heating. Then it will fire up.

Is the Water Level Low?

Hydronic heating systems have a very slow rate of temperature increase. Maintaining the water level in your boiler is critically important. It should always be at least half full, as with hydronic heating systems they will automatically refill using the pressure relief valve. The boiler system should self maintain a proper water level at 12-15 PSI (pounds per square inch). If no pressure reducing valve is present on your system you can manually fill the boiler by opening the water feed valve until boiler pressure reaches 12 PSI.

Are There Signs of a Thermostat Failure?

The two main types of thermostats, depending on the heating system you have, are ‘low voltage’ and ‘line voltage’ thermostats. Check first if the thermostat is set to ‘heat’ mode if you have one. Some thermostats have a ‘heat mode’ and a ‘cool’ mode.

Also, ensure that the temperature settings are normal. Try turning the heat up or down a few degrees to see if the thermostat kicks in. If not, it could be a thermostat failure and you will need to open the thermostat casing and check any relevant wiring. Check all the mechanical and wiring contacts and make certain they are all clean and all attached. Look for signs of burned wiring or scorched leads and connections.