Testing If Your Boiler Gauge is Stuck

boiler and surrounding pipes
  • 1-2 hours
  • Beginner
  • 0-60
What You'll Need
Garden hose
Sticky tape

A boiler is one of the most important installations in your home. It will regulate supplies of hot water and helps keep your central heating running at an efficient rate. If your boiler gauge gets stuck, you will need to get it replaced at the earliest opportunity. This will stop your boiler from operating inefficiently. Testing if your boiler gauge is stuck is a very simple procedure.

Step 1 - Take a Reading

Your first step is to take a reading of what the gauge is currently displaying. Write down the pressure and temperature readings on the gauge and cross check them against what a normal reading is considered to be in the boiler manual. Another tip is to place small pieces of sticky tape in the places that the gauge is pointing to as a guide. This will make it easy to see if the pointer is fluctuating.

Step 2 - Perform Basic Tests

Perform some basic tests such as flicking the boiler gauge two or three times with a finger. If the pointer in the gauge moves around violently, the gauge will not be stuck. You could also try temporarily putting hot water taps or heating on high settings. The temperature reader of the gauge should shoot up accordingly.

If it does not, the gauge is probably stuck. You could save yourself a lot of time by carrying out these basic checks first.

Step 3 - Check Pressure

Turn off all power to the boiler and turn off the water supply to the boiler. Take the garden hose and hook it up to the boiler, making sure it runs to the outside of your home. There should be a red valve handle on the draining pipe. This is the pipe you need to connect the hose to. Start draining water from the boiler by turning the red handle. The gauge should slowly decrease down to zero. If it does move, turn the valve off and reconnect the water supply. The gauge should go back up to between 12 and 20. If the gauge stays in the same place, it is stuck and needs replacing.

Step 4 - Check Temperature

Turn the boiler off for three or four hours. This will allow it time to cool. The temperature gauge should read between 100 percent and 200 percent after this time. If the temperature is exactly the same as the reading you took earlier, the temperature gauge is stuck and needs to be replaced. If the temperature reads over 200 percent then you have the thermostat set too high and you will need to turn it down.

Step 5 - Replace Gauge

If your temperature gauge needs replacing, you are advised to hire a gas engineer or plumber to do it for you. They will install a new gauge and carry out regulation tests to make sure it is working and the problem is not something to do with the boiler itself. They will check other dials and gauges for you. This will not cost too much and will save you an endless amount of time and money, especially as some states require special permits before work on a boiler can be carried out.