A boiler might not ignite due to various possible reasons – insufficient pressure, blockage in the burner, faulty valves, frozen pipes etc. Sometimes, you can fix the problem on your own. In other cases, you don’t have any choice but to call an engineer.

Why does my gas heating keep turning off?

Lack of water flow



If the boiler keeps shutting off, it could be due to closed valves, air caught in the system or a broken pump. The boiler is switching itself off due to in-built safety mechanisms – if it did not shut down, then the boiler could overheat.

Why will my heater not stay on?





Dirty flame sensor – Your flame sensor is an important component of your furnace, as it can detect the pilot light is working properly. If this sensor becomes dirty, the furnace will shut off. This is one of most common problems HVAC technicians see when diagnosing a furnace that has suddenly stopped working.

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.

Why does my boiler fire up then cut out?

Your combi boiler firing up then cutting out is nothing to worry about. It is usually the result of its ‘preheat’ function. Basically, it’s a way of ensuring that hot water is ready to be used in the taps throughout your home.

Why does my furnace only run for a few minutes?

If your furnace shuts down after a few minutes, it’s likely due to a faulty or unhygienic flame sensor. This crucial component intends to monitor the gas burner. Also, when a flame sensor cannot detect the burner, the furnace runs for a few moments before shutting down and restarting.

Why is my heater going on and off?





When a furnace keeps turning on and off, it is usually due to short cycling. This is the term used to describe problems originating from within the heating system. If short cycling is not promptly diagnosed and corrected, it could cause permanent damage to your heating unit and higher utility bills.

How do I stop my boiler short cycling?

Adding thermal mass to the heating system will decrease the burner short cycling and this can be done by adding water volume to the system. A relatively easy way to add thermal mass is adding a “Buffer Tank”.

Why does my furnace come on every 5 minutes?

Blocked Exhaust Vent



This is another cause of a furnace overheating and short cycling. Short cycle time: 1-5 minutes. This issue can be dangerous too, since deadly carbon monoxide is dispersed through the vent. If it is blocked, the gas won’t escape, and it can leak out of the furnace and into your home.

How do you know if your boiler is short cycling?

“Short cycling” is when a furnace or boiler keeps turning on then off for very short durations. A “short duration” in this instance is generally defined as less than a minute up to a few minutes long. Some short cycling heating systems will turn on and off after just a few seconds.

What does it mean when a boiler is short cycling?



Boiler “short cycling” occurs when an oversized boiler quickly satisfies process or space heating demands, and then shuts down until heat is again required. Process heating demands can change over time.

How do you fix short cycling?

How To Stop and Prevent Short-Cycling

  1. Check your air filter. Believe it or not, a clogged air filter can cause a wide variety of air conditioning issues. …
  2. Check your thermostat placement. …
  3. Check your air conditioner’s refrigerant levels. …
  4. Replace the low-pressure control switch. …
  5. Check the compressor.


Is short cycling normal?



One of the most common, and unfortunately harmful, problems an air conditioner can have is something called short-cycling. This is both a symptom of a problem and a cause of a problem. Sometimes a few simple adjustments may be all that’s needed to repair the issue.

Can a heater short cycle?

Frequent overheating results in your furnace turning itself off to prevent potential damage. Faulty temperature monitors will result in an inefficient system, leading to temperature swings and short cycling. An overheating furnace can cause more than short cycling.

How do you clean the ignition sensor on a furnace?


Quote from Youtube video: So if you have a situation like this what you have 90% of the time is just a dirty flame sensor. So we'll go through the steps on how to clean it. So the right side of the furnace.

What should I do if my furnace is short cycling?

If you suspect this is the reason your furnace is short cycling, it is imperative that you contact an HVAV professional to repair the unit. Restricted airflow is typically the cause of overheating which may be due to a dirty air filter or interior vents, or because roof exhaust vent is blocked.