The UK homes are characterised by boilers. A boiler can disappear in no time in the event of a boiler failure. That brings about stress, cold rooms and even expensive repairs. This manual will discuss the popular boiler issues that you would encounter in the UK. It describes easy tests that you can perform, the probable causes and when you need to contact an experienced engineer.
The guide also connects to government grants and schemes such as the Free Boiler Replacement Scheme.
You shall hear about these trite boiler failures:
- Boiler Not Heating Radiators
- Boiler Losing Pressure
- Boiler Not Firing Up
- Low Boiler Pressure Fix
- No Hot Water From Boiler
- Boiler Making Strange Noises
- Frozen Condensate Pipe
Boiler Not Heating Radiators
Part or all radiators remain cold even as the boiler is operating. The boiler can display normal pressure and can even start up, but rooms are cool.
Common Causes
- Radiator air that prevents the circulation of hot water.
- Radiator valves (TRVs) became stuck.
- Broken room thermostat/smart control.
- The circulation pump is not functioning or is too low.
- Existing systems older than 5 years old are blocked with sludge or limescale.
Checks You Can Do
Feel the radiators: Check where they are cold top or bottom. Warm bottom and cold top normally indicates stagnant air. Cold all over This may indicate a radiator valve that is closed or lack of circulation of the pump.
Test indicator (thermostat) and changing time: Ensure that the heating mode and heating temperature are properly adjusted. Check the app in case you have a smart thermostat.
Review boiler pressure gauge: Normal pressure measures between 1.0 and 2.0 bar with reference to the boiler manual.
Simple Fixes You can Try
Bleed the Radiators: Open the radiator to air using the radiator key till water forms. A towel and a small bowl to trap water should always be there. Work downwards to the radiator and upwards to the highest.
Open TRVs: Turn all thermostatic radiator valves completely on test. When a valve is stiff it may be stuck and require service.
Restart and reset thermostat or change the settings: The simplest thing to do to erase and clear up any scheduling errors is to reset the thermostat, or to amend the settings using the application.
Check pump: You may hear the pump running and radiators are cold: The speed of the pump may be too slow. This is usually an installation environment and can require an engineer to modify.
When to Call an Engineer
When the bleeding radiators fail to correct the situation.
In Case the Pump is Not Running
When bleeding radiators, in case of indications of sludge (brown, dirty water). Flushing of the system can be required.
In case you do not know what type of boiler you own (combi, system and regular), check this boiler types guide.
Boiler Losing Pressure
The boiler pressure gauge becomes lower than the usual state. The pressure might drop when heating on, or pressure drops slowly with time.
Common Causes
- Leakage of heating system (pipes, radiators, valves).
- Broken pressure relief valve (PRV) which allows water to come out.
- A defective expansion vessel which has stopped holding pressure.
- New system work which created air pockets or improper filling.
Checks You can Do
Look for visible leaks. Small leaks will decrease the pressure even in the long run.
Notice the time the pressure decreases: Does it decrease when running the heating or just at night? Leaks when the heating is on may indicate the expansion vessel or PRV.
Check the boiler ‘s fault-code: A large number of contemporary boilers will indicate an error when the pressure is low.
Simple Fixes You can Try
Re-pressurise the system: The majority of boilers have an under-boiler filling loop (a silver braided hose) or an under-boiler valve. Top up pressure in the boiler following the boiler manual to recommended levels. Do not over pressurise.
When to Call an Engineer
- If you suspect a leak. Water damage poses a great danger.
- In case the pressure keeps on decreasing following re-pressurisation.
- In case you are not at ease with filling the loop, then it is prudent to call a Gas safe engineer.
- In case of discharge of water by PRV or recurrent low-pressure problems exhibited by the boiler.
Boiler Not Firing Up
The boiler fails to spark at the demand of heat or hot water. There may be clicking without a flame or the boiler may malfunction and display an error code.
Common Causes
- None of the gas supply or closed gas valve.
- A faulty ignition or fan.
- An obstructed condensate pipe (on the condensing boilers of modern times).
- Safety cut-outs.
- Thermostat/ timer faults barring demand.
Checks You can Do
- Look into the display or app of the boiler and note down a code of error. The code will be described in the manual.
- The boiler should be activated and the timer / thermostat requesting that the boiler be turned on.
Simple Fixes You can Try
- Reinstate the boiler according to the instructions of the manufacturer. Frequently restocking a false lock-up can be obtained by a single reset.
- Test condensate pipe every cold weather to see whether it is blocked up – a frozen condensate pipe can prevent the boiler firing. Visit the frozen condensate section to know how.
- Check the timer to heat and make sure that thermostat batteries (if used) are good.
When to Call an Engineer
- In case the boiler keeps locking out due to a reset. There is a possibility of damaging parts because of repeated lockouts.
- In case of a supply problem with gas – call your gas supplier.
Low Boiler Pressure Fix
The firing of the boiler may be prevented by low pressure. It is also able to produce cold radiators and bizarre sounds. It is important to fix pressure in a safe manner.
Re-Pressurisation (General Procedures)
- Switch off the boiler and allow the boiler to cool. Approach the boiler to locate the filling loop (or filling valve); other boilers are those designed with an inbuilt filling mechanism.
- Close the filling loop gradually by turning on the valves until the level of pressure at the valve reaches the recommended period (approximately 1 to 1.5 bars when cold). Close the valves.
- Enable the boiler again and inspect the system checked.
Safety and Tips
- Do not leave the filling loop uncovered. This can over strain the system.
- In case you are not sure of the position of the filling loop then do not force anything. See reference manual or consult a good engineer.
- If you cannot retain pressure after refilling, invite an engineer.
No Hot Water From Boiler
The hot water might fail or both the hot water and the central heating fail. This is frequently observed in the first place in combi boilers when a hot tap goes dead.
Common Causes
- Hot Water broken sensor/flow switch.
- Sludge or slumber is clogging the heat exchange of hot water.
- Gas/ ignition faults, which stop the hot water mode.
Checks You can Do
Test other hot taps: Does it only have 1 tap or does it have all taps? A single one can be the issue of a mixer valve or tap.
Simple Fixes You can Try
- Clear an electronic fault by starting the boiler up again.
- With no hot water available on one of the taps, be sure to check the tap or replaceable cartridge before determining that the boiler is malfunctioning.
When to Call an Engineer
If the diverter valve is suspected. The replacement or repairing of the diverter valves requires an engineer.
Boiler Making Strange Noises
Several sounds may be produced by boilers: they may either knock, kettling (vociferous rumble), gurgling, or even whining fans and pumps.
Common Causes
Kettling: This usually happens as the result of the limescale on the heat exchanger. Water is incapable of flowing and becomes overheated.
Air in the system: This will gurgle as the water and air are pumped.
Malfunctioning pump bearings: Whining or squealing.
Checks You can Do
- Switch on heating, and be very attentive. Attempt to find out the source of the sound to be either the boiler, a specific pipe or a radiator.
- Vent radiators to get rid of air. When there are changes of noises, the cause could be air.
Simple Fixes You can Try
- Air can be removed and gurgling minimised by bleeding radiators.
- Check boiler pressure- extremely low or extremely high pressure may create noises.
- You can have old central heating and think that it has limescale, and an engineer can suggest that you should have it power-flushed or as an alternative, a magnetic filter installed to trim sludge.
When to Call an Engineer
- Kettling usually requires an engineer. When left alone, it has the ability to decrease the life of boilers.
- In case the pump is noisy or when the boiler starts making a loud impact noise.
- Any disturbing, repeated, and noticeable sounds must be checked.
Frozen Condensate Pipe
The advanced condensing boilers are drained into a waste drain via a small plastic pipe which pumps out acidic condensate water. This pipe may freeze in cold weather and to prevent this the boiler will have to be shut off.
How You Will Know
- The boiler exhibits a condensate fault or is not starting or it could have a particular error code.
- There is some frost or ice on the condensate pipe out there.
DIY Thawing Steps
- Discontinue any visible frozen portion of pipe by pouring warm (not boiling) water on it.
- Do not boil water because it may break plastic.
- Slowly pour water and keep on till the pipe thaws. Having a cloth to remove run-off.
- When a vulnerable and exposed pipe is used, cover the pipe with a lagging or insulation to avoid the freezing process.
Prevention Tips
- Wrap up exposed condensate pipes with sufficient foam lagging.
- Rerouting the condensate pipe through an internal wall, or a sheltered drain, is possible, with the exception of the drain being exposed to the outside environment.
An engineer is able to give advice and re-direct.
When to Call an Engineer
- In case of an inability to thaw or a recurring freeze of the pipe.
- A frost-resistant solution can be installed or the routing can be changed by an engineer.
- If the boiler has other faults during thawing- e.g. the boiler does not reset.
Tips: Maintenance and Prevention
The frequent attention will minimize the risk of the above issues. You must endeavour to do the following:
- Annual Service
This should be serviced by a Gas Safe-registered engineer once in a year. This ensures efficient and safe keeping of the boiler.
- Check Pressure Monthly
It is one habit that should be used to check the boiler pressure gauge after every month. Always top up when necessary and you have the idea how.
- Bleed Radiators Every now and then
Before winter. The trapped air helps in the removal that is useful in heating.
- Insulate Pipes and Condensate Run
Heat loss and freezing pipe lagging there.
- Be Aware of Leaking
Drops of drips may lead to loss of pressure in a month or so. Fix leaks early.
When It Needs To Be Replaced Not Repaired
Replacement may be better if:
- You have a boiler that is older than 12-15 years and it requires regular repair.
- Repair prices cost less than the cost of a new boiler by more than half.
- The boiler is ineffective and escalates your fuel importation charges.
- Home Energy Guide tells about New boiler costs; best boilers and when to replace boilers.
The Help Provided by Home Energy Guide
Home Energy Guide focuses on explaining grants and schemes, helping homeowners understand what support is available. Whether you’re dealing with recurring boiler issues or believe you may qualify for assistance, explore the ECO4 scheme.
Frequently Asked Questions (FAQs)
Loss in the pressures is typically referring to a leak or faulty expansion vessel. Initial scrutiny of visible leaks. In case they cannot be detected, an engineer might be required to test the system, repair the leaks or replace the expansion vessel.
Kettling is commonly a by-product of lime or a limited supply of water. Attempt to bleed radiators and get all the air out, however kettling may require an engineer to check the heat exchanger and suggest descaling, powerflush or replacement of components.
This in combi boilers can be as a result of a faulty diverter valve or flow sensor. On other systems, there can be an issue with an immersion heater or mixer valve. Often, diagnosis and repair is a task of a qualified engineer.
Wrap open pipes, run the pipe where feasible to a covered drain and in extreme cold conditions pour some warm (not boiling) water on frozen places to warm up.
