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Why Is My Gas Boiler Not Heating My Water? A New Jersey Tech Explains.

Nov. 18, 2016
There could be multiple reasons why your gas boiler isn’t heating your water, but these are the most common:
  • Your boiler isn’t receiving power
  • There’s a water leak
  • The water level in your boiler may be too low or high
  • The high-temperature limit switch is bad
  • Your thermostat is malfunctioning
  • The natural gas valve is closed
  • The boiler’s pilot light is off
In this article, we’ll show you how to troubleshoot these common boiler problems as well as other possible issues that prevent your boiler from heating water.

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How to troubleshoot your boiler

If your boiler isn’t heating water, start with these steps:

Check the power

  • Check your circuit breaker to see if you have a tripped breaker switch.
  • If your boiler doesn’t turn on after you reset the circuit breaker, check to see if you have a blown fuse. If you decide to replace the fuse yourself, make sure the new fuse has all the same ratings (voltage, current, etc.) as the blown fuse.

Check for leaking water

  • If there is any leaking water inside of the compartment, that could cause the boiler to malfunction. Call a trained technician if you find a leak. He or she will determine whether the leak is coming from your system’s pressure-relief valve, pipes, or pump.

Check water level

  • Most boilers have an automatic water filling system that’s controlled by the pressure-relief valve. The water level in your boiler should maintain 12 to 15 psi (pounds per square inch) pressure. If the water pressure in your boiler is above or below this range, your boiler won’t work as efficiently. To know how to add or remove pressure from your specific boiler, contact a trained technician.

Check the high-temperature cutoff in the water heater

  • Make sure the boiler has cooled down.
  • Open the panel on your boiler and push the reset button.
  • If it doesn’t turn back on after pressing it, it’s possible the high-temperature limit (cutoff) switch is bad. A high-temperature limit switch turns off your boiler if there is any overheating. You’ll need a water heater expert to take a look at it for a diagnosis. 

Take a look at your thermostat

  • Make sure your boiler thermostat is in heat mode with an appropriate temperature setting. Over time, older thermostats can become less accurate by misreading temperature settings or even turning on/off by itself. Try moving the setting up or down a few degrees. If you do not notice any change, call a certified water heating expert.

Make sure the natural gas or propane control valve is open

  • When people leave their homes for an extended time, sometimes they’ll close their natural gas control valve for safety. Make sure this valve is open so that gas can reach the boiler.

Check the pilot light

  • Gas boilers have a light called a standing pilot or pilot light which serves as a small ignition flame for the gas burner. Older boilers typically require you to manually ignite the standing pilot if it goes out, while newer boilers have automatic starters that relight the standing pilot.
  • You can carefully relight the standing pilot yourself, or you can contact a water heating expert to do it for you.

Boiler still not working? Call a certified professional.

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