How to Check Gas Central Heat in a Boiler System

Programmers and Timers

• Make sure the programmer, timer and boiler on your central heating system are receiving power and are switched on. Inspect the programmer or timer to make sure it's set to turn on and off at the correct time of day. If you're using a mechanical device, such as a mechanical timer switch, make sure it isn't stuck. If the moving parts of the timer have seized up or become obstructed, it won't trigger your boiler to come on and turn off as programmed. Check the controls on the furnace to make sure they're configured properly. Consult your boiler's manual for instructions on how to do this. If the programmer or timer is defective, it will need to be replaced.

Thermostat

• Establish the age of your thermostat. Older thermostats can lose the ability to accurately calculate heat over time. Look for the date of manufacture on the thermostat itself. Consider replacing it if it's more than eight years old. If you can't find a date of manufacture, inspect the thermostat for signs of wear. It may be worth investing in a new energy-saving thermostat to regulate the temperature. Thermostats are easy to install and can help cut your heating bills by using fuel more efficiently.

Boiler Pipes

• Troubleshoot the pipes in your central heating system by first turning off the boiler. Wait for the pipes to cool down then make sure they're properly connected to the walls and aren't leaking. Inspect the brackets that secure the pipes to the walls and the connectors that join them to the radiators. If the brackets are loose or you find a leak, use a screwdriver to tighten the brackets or a spanner wrench to secure the pipe connectors. Pipes that are rusted or have perforations will need to be replaced.

Bleeding

• If the top half of the radiators remain cold when the heat is on, it's likely there is too much air in the system. Shut off your central heating system and wait for it to cool down then use a bleed key to open the air valve at the top of the radiator. This will allow excess air to escape. Have an old towel and a pan on hand to catch any excess water. If you have a sealed central heat system, you'll need to reduce its pressure before bleeding the radiators. Refer to the user's manual for your furnace, which will have detailed instructions on how to do this.