Many homeowners find themselves in a situation where the boiler turns on when the thermostat is off.
Your boiler turning on even though the thermostat is off, usually happens because of a malfunctioning heating circuit or sensor, but there are other things that could cause it to turn on as well.
A fault with your thermostat may also cause your boiler to constantly fire up.
If you’re not sure what the issue is, contact an expert for help. They can inspect your heating system and figure out why this is happening to ensure that everything runs smoothly again soon.
Preliminary checks if your boiler keep running
If you want to do some initial checks and have a look at what might be causing the problem below are some checks you can do.
If the boiler keeps running, it may be because of one of these issues.
- The thermostat is not wired in correctly
- Fault with the heating circuit
- Pilot light or pilot assembly has gone out
Check the Thermostat
If your boiler keeps firing up when the thermostat is off, it may be because of a faulty thermostat.
The thermostat might not actually be setting the system to “off” when instructed to.
You can test this by listening for the boiler click when you set it to “off”. If you don’t hear this noise and your boiler keeps firing up, you probably have a problem with the thermostat.
If you can remove your thermostat, place it face down on a flat surface and open the back.
You may find a blown fuse, loose wires, or another issue that can be repaired.
If this is the case, you should contact a professional to fix or replace your thermostat yourself.
Check the Heating Circuit
Sometimes, the heating circuit will begin to malfunction if there’s an issue with any of its parts
For example, one of the wires might have loosened over time, so it affects the electrical system enough by restricting its conductivity.
In this case, your boiler will probably keep firing up even though the thermostat is set to “off”.
The circuit will also likely trigger the emergency switch in time so that you don’t suffer from a lack of heat when at home.
If this is your issue, you should contact a professional to fix it for you.
Check the Pilot Light
In some cases, the pilot light on your boiler may have gone out.
This will cause the boiler to constantly turn on because it thinks that the heating system isn’t working, so it keeps setting itself back into action.
Check the shut-off temperature controls, in particular the low-temperature switch.
This usually keeps the boiler turned on if it thinks that the water inside is not being heated to its optimal temperature.
If this is the case, you should be able to see that the low-temperature switch is set far below room temperature.
You should also check the temperature of the water.
You might need to remove the control switch and then retest your boiler. Carefully examine all of the wirings, and replace any loose wires or fuses before trying the power again.
What should a boiler thermostat be set at?
Once you have your thermostat working, it’s important that you set it to the right temperature.
This can vary depending on where you live and what time of year it is.
A general rule of thumb for heating is that between 18 – 22 degrees Celsius should be maintained in most rooms throughout the winter. When the room temperature reaches this setting on the thermostat, the boiler should shut off.
Sometimes, you may find that your boiler is turning on and off too many times in a day. This may be due to the thermostat being set too high or too low
If it’s set too high, this causes the system to constantly turn on and off because it doesn’t recognise when it’s reached the desired temperature.
If it’s set too low, this causes the boiler to constantly come on because it thinks that the temperature in your home is still cold.
In this case, you should adjust your heating system so that it turns off when you want to heat and turns on when you need warmth.
This will allow your heating system to only switch on when the temperature falls below the desired temperature.