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Central Heating Problems – Advice & Help

This web page contains information that will help you solve many central heating problems. This web page describes problems and possible solutions.

 

The Judge Electrical central heating problem symptoms web page is a list of symptoms with links to possible solutions – bullet list format; their is not so much text describing the problems.

 

The advice is for the average ‘DIYer’ with links in the text to more detailed information.

 

Single Radiator Not Working

Bleed the radiator

 

Radiator blocked with sludge?

 

Thermostat set correctly?

 

Thermostatic radiator valve (TRV) OK? TRV information

 

Radiator leaking? Single radiator leaking

 

Further help – single radiator not working

 

Radiator Hot At The Bottom But Cold At The Top

Bleed the radiator

Further help – single radiator not working

 

Radiator Hot At The Top But Cold At The Bottom

Bleed the radiator

 

Sludge in the radiator?

 

Further help – single radiator not working

 

All Radiators Not Working

Is the boiler pilot light lit? The pilot light should be visible through a small ’viewing window’ – a small, usually round, clear window on the boiler.

 

Does the boiler sound the same as normal? Does the boiler make the same noise when it is turned on?

 

Is the thermostat in a hot part of the room or house? The thermostat should be in a cold part of the room or house so that it turns the central heating on when it is cold. Has something that gives off heat, for instance an electrical appliance, been put near the thermostat? Is the heat from an electrical appliance ‘fooling’ the thermostat into thinking it is hotter than it really is?

 

Are the radiators hot upstairs but not downstairs? Hot radiators upstairs but not downstairs could mean that the pump is broken or ‘on its way out’ – the pump does not have enough power to pump the water up in height. Does your central heating system have ‘zone control’ (can control the heating to different parts of the house) – is the zone control set correctly?

 

Does turning the radiators off in one part of the house make the radiators in another part of the house heat up and vice versa? This indicates a pump ‘on the way out’ or a ‘clogged up’ central heating system. The pump may need replacing or the central heating system flushed out – or both.

 

Hot Radiators Upstairs But Not Downstairs – advice & help to solve this problem.

 

All Radiators Downstairs Cold – possible explanations.

 

Single Radiator Not Working – possible explanations.

 

If the boiler does not make any noise when it is turned on, it seems completely ‘dead’, the problem could be the electrical supply to the boiler.

 

Check the electrical supply to the boiler.

 

The electrical supply to the boiler will usually be by means of a wall outlet (see image below), is the supply on?

 

Is the fuse indicator light on? Turn the supply on or change the fuse if necessary. Check the RCDs.

 

Fused mains electrical outlet

 

 

Central Heating Boilers – Information about central heating boilers.

 

Central Heating Boiler Problems – Advice & Help – advice and help on solving common central heating boiler problems.

 

Central Heating Timer Clock Not Working

The most common cause of central heating timers not working is the timer clock is not set to the correct time. Clocks can be reset without the homeowner knowing, for instance a short mains ‘power spike’ can reset the clock. Check the time on the timer.

 

Replacing a central heating timer is fairly easy and can usually be done by a competent ‘DIYer’. The connections to the timer are usually ‘standard’ (each make of clock has the same connections). Replacing the timer is usually a cheap and easy option.

 

Turn the supply to the timer off – this will ‘reset’ the timer and solve some problems – the switch is usually near the central heating boiler or the central heating control mechanism. The clock and on\off times will need to be set after removing power to the timer.

 

Does the central heating control mechanism have a reset switch? The switch is usually on the side of the mechanism; press the reset switch. The clock and on\off times will need to be set after resetting the timer.

 

Is the clock on the timer correct? Is the timer set to the correct time? Is the timer clock set to AM when it should be PM?

 

Does the timer have a ‘zone control’ option? Some timers allow you to turn different parts of the central heating system on and off at different times, for instance upstairs and downstairs. Is the zone control set correctly?

 

Is the thermostat set correctly? The timer could be operating correctly but the radiators are not heating up because the thermostat is set too low.

 

Is the thermostat old? Over time a thermostat will lose accuracy or stop working all together; try a new thermostat.

 

Thermostats – what a thermostat is, what central heating system thermostats are used for; shows what central heating thermostats look like.

 

Central Heating System Making Funny Noises

Air in the central heating system causes most ‘funny noises’ – loud banging, ’hammering’ – bleed the radiators.

 

Tightly fitting pipes can cause ‘creaking noises’. If central heating pipes are a tight fit to floors or walls you will get creaking noise as the pipes heat up and cool down – pipes expand when hot and contract when cold. To solve this problem make the holes that pipes go through slightly bigger.

 

Central Heating Noises – what can cause different types of noises.

 

Banging Noise – possible explanations.

 

Humming Noise – possible explanations.

 

Boiler Controls Not Working

Is the timer set to the correct time? The correct day? AM or PM?

 

Is the thermostat working correctly?

 

Electronic controls? Check the display – does the display look OK?

 

Is the TRV set correctly?

 

Is the lockshield valve set correctly?

 

Boiler problem help

 

Central Heating Boiler Faults

There are many different types of boilers, timers, thermostats, pumps, valves and heating systems used in domestic and commercial applications; this is what makes diagnosing boiler problems difficult to the inexperienced person.


No power to boiler or central heating timer clock – they look ‘dead’ – check the fuse which is in the ‘fused spur’ which should be near the boiler or the clock or both. If the fuse is OK, has the RCD tripped?

 

Electrical RCDs – Find & Reset An RCD + Investigate a Constantly Tripping RCD web page


There are fuses in the boiler which can blow, call an expert to change them. If the boiler fuses have blown the central heating control clock works but the power lights on the boiler are not lit.


Boiler heating the hot water but not the central heating – a common problem after not using the central heating for some time. Give the central heating pump and pump valve a ‘love tap’ – a gentle tap with a hammer. A ‘love tap’ sometimes ‘frees’ a sticking pump or valve.


Is the thermostat in a hot part of the room or house? The thermostat should be in a cold part of the room or house so that it turns the central heating on when it is cold. Has something that gives off heat, for instance an electrical appliance, been put near the thermostat? Is the heat from an electrical appliance ‘fooling’ the thermostat into thinking it is hotter than it really is?


Boiler heating the central heating but not the hot water – Could be a problem with the cylinder thermostat or central heating valve problem. Give the central heating pump valve a ‘love tap’ – a gentle tap with a hammer. A ‘love tap’ sometimes ‘frees’ a sticking valve.


Is the boiler timer working? It could be the boiler timer is not asking the boiler thermostat to heat the hot water.


The central heating does not light up (seems dead) or respond and the boiler doesn't work – does the central heating timer have power going to it? Has a fuse blown or RCD tripped?

If the clock has power going to it this suggests the central heating clock is broke.

 

Please contact Judge Electrical for free central heating advice.

 

Judge Electrical Ltd Central Heating Guideline Prices

 

Judge Electrical Limited
15 Mulberry Court, Huntington, York, YO32 9TU
Telephone 01904 764845 (Landline), 07919 033113 Mobile)
Email info@judgeelectrical.co.uk
VAT No. 852917405. Company Number 6359328