Why does my boiler keep firing up when heating is off?

Pre-heating

You might hear your boiler fire up from time to time, even when the heating is off and you're not drawing any hot water. This is completely normal, and is there to ensure you have hot water when you turn it on.

Why does my system boiler keep firing up when heating is off?

A faulty thermostat may not measure the temperature accurately, causing the boiler to cycle on and off more frequently. You'll also want to consider the location of the thermostat. If it's in a particularly cold spot then it will prompt the boiler to keep firing up.

Why does my boiler keep turning on by itself?

This is perfectly normal and doesn't indicate a fault with your boiler, your boiler is just turning itself on to pre-heat water so that it's ready on demand when you need it. If your boiler is turning itself off and on again every few minutes then we are looking at a potential issue called 'short-cycling'.

Why is heating still on when switched off?

Radiators coming on when thermostat is off. If the anti gravity valve is broken or blocked and is not doing its job of stopping the natural convection process, it means heat will rise through your central heating system. Your radiators will be on, even though your thermostat is off.

Why is my boiler not turning off?

A thermostat fault may be causing your boiler to continue to fire up and stay on. You could attempt to test this issue yourself by turning your thermostat temperature levels down to see if this brings about any change, you could also try to replace the device's batteries.

My boiler keeps firing up even though the timer for hot water

Why does my boiler come on in the middle of the night?

It's true that boilers do turn on from time to time during the night. Combi boilers work best when the heat exchanger inside is kept warm, so it will need “topping up” a few times overnight to make sure you have instant hot water when you need it.

Should my boiler run constantly?

The general rule of thumb is, anything over 8-10 cycles per hour can be considered excessive. This can vary, depending on your facilities unique circumstances and more could be “normal” and fewer could be “excessive”. Boilers can cycle for a variety of reasons.

Why does my boiler pump keep running?

If the pump is always running, there are generally 3 causes for this: The speed control wire (purple, white and black) going to the pump is damaged - check continuity and connection. The boiler has a weather compensating controller fitted (FW100 or Wave smart internet connected controller).

What causes pump overrun?

Pump overrun is a normal function of a heating system. After the boiler has been switched off, the pump circulates the water to dissipate any residual heat. Pump overrun should last 5-10 min, or until the water cools down enough. If you have thermostatic radiator valves on all radiators, then a bypass is required.

How long is pump overrun?

Pump overrun should only last about 5-10 minutes, or until the heat dissipates. If the pump is running for hours on end, or constantly, there may be an issue with the system. Possible causes are a faulty pump overrun thermostat or timer, or a damaged PCB (Pump Circuit Board).

How do I know if my central heating pump needs replacing?

How do I stop my boiler from short cycling?

In a fully automatic central heating system the short cycling of the boiler can be prevented by using the room thermostat/programmer and hot water cylinder thermostat to switch on the electrical supply to the boiler.

Why does my Vaillant boiler fire up randomly?

This could be due to the comfort feature being active. This is displayed on the screen with a c symbol. Just turn the hot water control all the way to 0 then back to your desired temperature. The c symbol should now of disappear.

How often should boiler fire up?

It should do it once every hour or two, and each time will last a couple of minutes. Again, this is perfectly normal, so you don't need to do anything. If it's turning on regularly then turning off, and doing this repeatedly, that's more likely to signal a fault.

Can a boiler explode?

While historically, boilers would over-pressurise and explode with alarming regularity, modern boilers are manufactured to be able to withstand excessive pressure, and can typically handle an operating pressure of 20 PSI. When pressures increase beyond this level, the boiler can fail, which can lead to an explosion.

Why does my Vaillant boiler keep turning itself on and off?

There can be a number of reasons why your Vaillant boiler keeps turning off. It could be due to low water pressure, a faulty thermostat, a faulty water pump, air in the system or frozen condensate pipes. One of our engineers will be able to find the issue and quickly apply a solution for you.

How long should boiler fire?

Generally speaking we want a boiler to fire at least 15 minutes before shutting the burner off on high limit.

How do I stop short cycling?

How long does a central heating system last?

The level of maintenance and whether or not the system was professionally installed also affects service life. Typically, though, furnaces will last 15 to 20 years, while boilers can last up to 30 years, depending on the quality of the water supplied to the system.

What is the life of a central heating pump?

As long as your central heating system is correctly installed and properly maintained, you can expect the pump to last for a long time. Typically, they keep going for well over 10 years, with some lasting 20 years or more.

What setting should central heating pump be on?

By varying the settings, you can identify the most appropriate speed for your pump. Theoretically, the optimal speed settings in a central heating pump should ensure that there is 11 to 12-degree variance in the temperature of the water that is leaving the boiler and the water that is being returned from the radiators.

Do boilers need pump overrun?

Most modern heat only boilers need to use pump overrun to dissipate residual heat and reduce the risk of water boiling in the heat exchanger when it is switched off.

How do you reset a logic Combi 30 boiler?

REsET PROCEDURE

To reset boiler, turn the mode control knob (D) to reset position and immediately turn knob back to required setting. The boiler will repeat the ignition sequence. If the boiler still fails to light consult a Gas Safe Registered Engineer or in IE a Registered Gas Installer (RGII).

Is it safe to reset boiler?

If your heating isn't coming on and you've checked the power supply and pressure you may need to reset the boiler. It's a very simple and safe thing for you to do in your own home.

What pressure should my combi boiler be?

What pressure should combi boilers run at? The pressure of your combi boiler should be between 1 and 1.5 bar. If your pressure reads at less than 1 bar, it's possible that you have lost water from the system via a leak.