Boiler issues

Common boiler and system issues. 

Click on link’s below or scroll down. 

  1. Boiler Leaking
  2. Boiler not switching on
  3. Radiator issues
  4. Low boiler pressure
  5. Frozen Condensate Pipe
  6. Boiler or system noisy
  7. Pilot light not alight (old type boiler)
  8. Boiler Breakdown
  9. No hot water or Heating
  10. Thermostat not working
  11. Timer Blank
  12. Oil Boiler not working

Lots of heating problems are due to not understanding the system and how it works. We can help by coming round to inspect the system by maybe coming to service the boiler and at an (hourly rate) helping you to understand the system for the future. 

Boiler leak

A boiler leak is usually caused by an issue with a part inside, such as a pressure valve. If the leak comes from your pressure relief valve, it is likely that your system’s pressure has become too high. due to the expansion vessel being faulty or its been over filled. (Pressured systems only) 

If a  leak that has appeared around your boiler’s pipes could be caused by a faulty seal or pipe corrosion. In this case we recommend that you seek advise from a Gas Safe Engineer to help identify and fix this issue and I some cases you might need to get a new boiler installed.

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Boiler not switching on

If your boiler is not responding to your room thermostat, Can you hear a click?

  • Can you see the display?
  • Do you have Hot Water?
  • Is it Battery operated?
  • Wireless device, Faulty?
  • Faulty Controls?

70 % of heating breakdowns with the new thermostats is the batteries need replacing. Some have a manual override button near the boiler or in the airing cupboard. Failing all the basic check give us a call to arrange an engineers visit.

Gallagher Boilers

Radiator issues

If you radiator is cold on the top and hot on the bottom then it might need bleeding. Cold patches in the middle or bottom are usually caused by a build-up of sludge inside of radiators. Chemical or Power-flushing can help but in some cases a new radiator will be needed – Lots of radiator issues can be resolved by bleeding the radiator yourself.

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Low Boiler Pressure

Low System pressure is usually caused by an issue with a part inside the boiler, We find poorly maintained boilers tend to end up with pressure issues and it turns out to be a fault with the expansion vessel coincidentally it will blow the pressure relief valve then leak outside. If the leak has come from your pressure relief valve, it is likely that your system’s pressure has become too high which could be due to the expansion vessel being faulty or the system has been over filled. (Pressured systems only)  If a  leak that has appeared around your boiler’s pipes could be caused by a faulty pipe seal or from an ongoing drip,  now causing pipe corrosion.

In this case we recommend that you give us a call to arrange an engineers visit and I some cases you might need to get a new boiler installed.

Gallagher Boilers

Frozen Condensate Pipe

This issue is very common, particularly in the colder seasons. Your system’s condensate pipe is responsible for transporting the condensate from your boiler to your outside drain. During periods of cold weather, the condensate can freeze and cause a blockage to occur. This is particularly common in homes where the condensate pipe is fitted externally or in an unheated space such as a garage. This issue could cause the condensate to revert back up into the boiler and lead to the system breaking down.

Luckily, you should be able to fix this problem quickly and easily by yourself. Lagging or insulating the pipe can often be a long-term solution for this issue.

Take a look at a BAXI video guide on how to defrost a condensate pipe.

Boiler or System Noisy

It’s normal for your boiler to make some noise whilst it’s in operation, especially when it’s firing up. However, if your boiler suddenly begins to make unusual gurgling, banging or whistling noises, we recommend getting in touch with to arrange an engineers visit.

Unusual boiler noise can be caused by air in the system, a faulty pump, low water pressure or even a build-up of limescale known as “kettling.” 

Pilot light not alight (old type boiler)

Older boilers may have a permanent pilot light which needs to stay lit in order to light the larger burner within your boiler. If this light keeps going out there could be a faulty thermocouple that is cutting off the gas supply. Alternatively, there could be a deposit build-up or a draught blowing the light out.

You could try to reignite the pilot light yourself if you are comfortable doing so. Please follow the instructions in your boiler manual. Before you do this, you should ensure that your gas stopcock is on and that there are no issues with your gas supply – you can check other gas appliances to confirm this. We recommend contacting a Gas Safe registered engineer to help solve this issue.

This fault is more common with older boilers, as modern systems are not built with pilot lights and ignite electronically. If the issue with your pilot light persists, it may be worth getting a new boiler installed.

Boiler Breakdown

Poorly maintained boilers can lead to excessive boiler breakdowns, A regular serviced boiler can help reduce boilers issues or at least rectify any issues before they become a breakdown.

If you have a airing cupboard you may have access to an immersion heater that could provide you with hot-water.

Age and inefficiency can also cause boilers to breakdown beyond repair. If you have an old, inefficient boiler, we recommend investing in a new boiler so that you can get the heating and hot water you need. A new modern boiler will be up to 35% more efficient to run and will lower your bills

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No Hot water or Heating

No heating or hot water can be caused by many things, controls timer or faulty motorised valves, broken system diaphragms and airlocks, to low pressure or a broken thermostat.

To determine whether this issue is caused by low pressure, you should check your pressure gauge to see if it is below

1. If it is, it may need repressurising. (Worcester Boilers video)

If the intermittent heating and hot water is caused by an issue with your thermostat or other things that can cause an issues such as a broken motorised valve or faulty diaphragm will require a professional.

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Thermostat not working

This is becoming a common problem with the Thermostat on a modern heating systems because lost of the new thermostats are wirelessly controlled, This saves expensive wiring being added to the house with any new update of the boiler or system.

Things to check are is the display on the control working?

Is there a flame sign in the display?

Near the boiler or in the airing cupboard there will be a receiver of the same make, e.g. Honeywell, Drayton…….etc, Is there a light on it? Red normally indicates a fault, Green is good. Does it come on or off with turning the temperature up or down. 

If it does then it could be a valve or boiler issue.

Give us a call. 

Gallagher Boilers


Timer Blank

This could be a power switch been turned off by mistake or the fuse board that has tripped due to an electrical fault within the system. 

A water leak, batteries if it has a battery back up or maybe just a faulty clock. 

If you can’t find any problems the give us a call. 

Gallagher Boilers

Oil Boiler not working

One of our biggest oil boiler problems are running out of oil, Make sure you know how to check the oil level in your tank.

  1. Push and hold a button.
  2. Pull and hold a button.
  3. A valve on the tank gauge,
  4. Wireless plug in device connected to the oil tank.

All oil boilers have a reset button on the burner or boiler (the engine in the case) most of them are red or orange if it is lit then press it and the boiler will make some noise and after a few second “boom” it lights, Don’t try it more than 3 times. If it does go we call that a glitch. Maybe an annual service is needed. 

If the light comes back on then its indicating a fault,

  1. Motor or oil pump seized. 
  2. Control box or transformer broken.
  3. Coil or Photocell

If it still doesn’t work then give us a call

Gallagher Boilers

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