Common Gas Boiler Problems

The gas boiler is one of the most common unit that is used in family homes. They are efficient, easy to maintain, and do a great job at distributing the necessary heat throughout the entire home. Unfortunately, as much as we try to be careful when using the unit things will inevitably go wrong. Whether from wear and tear or mechanical failure problems can occur. The hardest part is knowing what went wrong.


The biggest problem you will deal with is the lack of heat being produced. This is often caused by an unnatural alteration in the water level or in the atmosphere inside of the unit. This will cause mineral deposits to build up. The easiest way to fix this problem is to flush out the whole system.

If that does not work than you need to check the tridicator that measures the pressure and temperature of the boiler. If the pressure if under 12 psi it means that you need to add more water by opening the water valve until it reached the appropriate level.

Expansion Tank

More often than not a problem will occur inside of the expansion tank. This is usually caused by an overflow of water or not enough air. The first thing you should do is to find where the tank is at. The older units will be in the attic – but the newer ones are usually in the ceiling. Be sure that the air is being carried into the tank properly so that the water level pressure is not too high.

You can also compare the temperature of the top and bottom of the tank. The bottom should always be hotter. If it is not than you should unplug the boiler, close the water supply, and wait a few minutes for it to cool down.

If this does not work than you need to drain water. Connect a hose to the purge valve on the tank. If there is no valve than unplug the valve that sits between the boiler and the expansion tank.