If you find that your boiler pilot light keeps going out and will not stay on, there are several things you can check and fix. Below is a list of reasons why this may be happening to your boiler.
1. Pilot Is Dirty
Your pilot light may be going out because it is simply dirty and filled with soot. Soot usually collects on the thermocouple. To restore the dirty thermocouple and pilot, take out a rag and a little warm soapy water and give it a good clean. You can use Q-tips to get around the little edges and corners.
2. Thermocouple Is Old
An old thermocouple may malfunction because it is worn out and needs to be replaced. This will cause your pilot light to go out.
3. Gas Valve Problems
The gas valve may be worn or malfunctioning. Check it and replace it if necessary. This should be replaced by a certified HVAC contractor that is familiar with your type of boiler.
4. Seal Is Not Sealed
Check the seals. If they are no longer forming a complete seal, you may want to replace them.
5. Overheat Switch
Many boilers have a switch that detects overheating. Check the switch to see if it is tripping. The thermostat may be a problem causing this to occur.