Frequently asked questions
My central heating does not work and my boiler is brand new?
When a boiler is installed on an existing central heating system, it is essential that the system be chemically flushed out to remove any build up of 'sludge' (generally iron oxides). The system should then be refilled and treated with a corrosion inhibitor / protector.
Failure to carry out this procedure (as specified in the Benchmark Central Heating Log Book) during installation may cause the new boiler to be contaminated by debris from the existing system. Because 'modern' boilers hold less water and are much smaller than their predecessors, they are more liable to be affected by debris in the system: heat exchangers, pumps or divertor valves are most at risk.
Also, the guarantee of the boiler can be deemed void if the debris from the old system damages your new boiler.
Is my central heating system covered by the boiler's guarantee?
The manufacturer's guarantee refers solely to the appliance supplied.
For example: If you have had a new boiler added to your existing central heating system and it is leaking causing regular introduction of fresh water or be contaminated with sludge due to improper installation (lack of inhibitor or proper flushing out), the operation of the boiler will be affected.
In such an instance the central heating system may detrimentally affect the performance of the boiler and therefore invalidate the boiler guarantee.
How often should I have my boiler serviced?
We strongly recommended that your boiler be serviced annually. Your guarantee will become void if you don't have your boiler serviced annually, should the fault be such that it would have been recognised in the normal annual service.
What is a condensing boiler?
A condensing boiler is the most efficient boiler available. It converts more than 88% of the fuel it uses into heat, compared to 72% for conventional types.
Condensing boilers have either a larger or second heat exchanger which saves the heat which would normally escape up the Flue in normal boilers. This reduces the temperature of the Flue gases to a point where water vapour produced during combustion is 'condensed out'. Hence the name 'condensing boiler'.
Condensing boilers are established products and can be fitted to most new and old heating systems. They are easy to install and can be bought for oil and gas-fuelled homes, even LPG (liquefied petroleum gas). These boilers are often no larger than conventional boilers. You can buy condensing boilers as either combination boilers, which heat up hot water on demand, or conventional system boilers, where a separate hot water cylinder is required.
What is a high efficiency boiler?
A high efficiency boiler is the most efficient boiler available. It converts more than 88% of the fuel it uses into heat, compared to 72% for conventional types.
High efficiency boilers have either a larger or second heat exchanger which saves the heat which would normally escape up the Flue in normal boilers. This reduces the temperature of the Flue gases to a point where water vapour produced during combustion is 'condensed out'.
High efficiency boilers are established products and can be fitted to most new and old heating systems. They are easy to install and can be bought for oil and gas-fuelled homes, even LPG (liquefied petroleum gas). These boilers are often no larger than conventional boilers. You can buy high efficiency boilers as either combination boilers, which heat up hot water on demand, or conventional system boilers, where a separate hot water cylinder is required.
What is a system boiler?
A system boiler is used for the central heating system; it is factory fitted with all the components needed for use with an external indirect cylinder for the production of domestic hot water.
System boilers neatly incorporate a number of components found outside of the boiler on traditional installations - the pump for example. Another is the Expansion vessel, which replaces the tank in the roof-space. So installation is easier and quicker and the risk of burst pipes in winter is eliminated.
What is a traditional boiler?
Traditional boilers (also known as heating only boilers) are used for the central heating system. Traditional boilers can deliver hot water to several taps simultaneously via an indirect hot water storage cylinder which is required as well as the boiler.
What is a combination boiler?
A combination boiler provides central heating and heats water instantaneously whenever you open a hot tap, so you don't need space for a storage cylinder and the hot water supply is endless. The temperature at the tap is dependent on the temperature of the mains supply and the Flow Rate.
Combination boilers are ideal for smaller one bathroom properties without the frequent and simultaneous use of sinks, showers, baths, washing machines and dishwashers. Because a combination boiler heats water instantaneously as you turn on a tap, it helps save on fuel and helps save on space as you don't need a cylinder to store hot water until it's needed.
Can I fill a system with softened water?
Water supplied via a water softener should not be used to fill any central heating system unless a corrosion inhibitor specifically formulated for the purpose has been added. Moreover, softened water should not be used where the system contains aluminium under any circumstances.
Because the chemical composition of softened water is very variable, we recommend that filling a system with it should be avoided by turning off the softener whilst the system is filled, if possible.
Why is system flushing important?
Flushing of a central heating system in accordance with BS 7593 is carried out to remove contaminants such as flux residues, grease, jointing compounds, oxides produced by the corrosion process, bacteria and in hard water areas limescale.
If they are not removed, these contaminants form a harmful sludge in the system which reduces the efficiency of the system, causes noise and could potentially reduce the useful life of the appliance.
Does the system need an auto by-pass?
Some of the boilers already incorporate a by-pass, however where all radiators are fitted with thermostatic radiator valves it is recommended an automatic system by-pass is fitted.
My system comes on during the night or in cold weather when not asked for?
Check the minimum room temperature setting; this should be a low temperature setting e.g. 8° to 12°.
Can 90-degree bends be used on vertical flue systems?
Yes, On our condensing boilers you can fit 90 degree bends to a vertical Flue systems. Note: A 90° bend is equivalent to 1.3 m length of Flue. If it is necessary to use a 90° bend in the vertical Flue, ensure the Flue above it is sloped towards the boiler to ensure that all condensate is allowed to drain from the Flue. The slope must be a minimum of 25 - 30 mm per metre.
What is the maximum equivalent length of a boilers flue?
The maximum horizontal equivalent Flue length (after the boiler turret) is 12m for CD Models and 3 meters for HE models. Allow 1.3 meters of Flue length for each 90-degree bend, 0.9 meters of Flue length for each 45-degree bend.
The maximum equivalent vertical Flue length is 15 meters for CD models and 6 meters for HE models. 90 degree bends are not to be used. Allow 0.9 meters of Flue for each 45-degree bends.
Where can I find out about grants for home heating?
Grants are available for a number of energy saving heating systems. To find what is available and if you are eligible visit the Energy Saving Trust website.
What happens to my old boiler if I have a new one fitted?
Most components from old boilers are recyclable at local recycling centres that have provision to dispose of metals
How are high efficiency condensing boilers more efficient than standard efficiency boilers?
High efficiency condensing boilers are able to capture and use much of the heat that old non-condensing boilers waste and release into the atmosphere. Condensing boilers convert around 90% of fuel into useful heating, whereas old conventional boilers only convert around 60% and waste the rest. All new gas boilers in England and Wales must be condensing boilers.
Are there restrictions as to where boilers can be sited?
Generally boilers can be sited wherever you like. All they require is flueing to the outside and to meet all building regulations.
I'm extending my home - will I need a new boiler for the new section of the house?
The capacity of your existing boiler will have been matched quite closely to the size of your home – the floor space and the number of bathrooms – in order to achieve maximum efficiency. If you are just adding one radiator for a new conservatory you will not need to replace your boiler, but if more radiators and hot water are required you should contact a heating adviser to find out if a new boiler is needed.
How much can I save by reducing my heating and water temperatures?
Reducing your room temperature by 1°C could cut your heating bills by 10%. Setting your water cylinder temperature to less than 60°C and fitting approved thermostatic mixing valves will also help save money.
Do solar power systems work when the sun isn't shining?
Our SolarSmart system is able to work even on cloudy days because it uses diffused radiation as well as direct sunlight. In the UK, it can supply almost all of your hot water in the summer and about a third during the rest of the year.
If I change my old boiler for a new one, how much can I expect to save?
If your boiler was installed prior to 2003, you could save a third on your heating bills and reduce your home's CO2 emissions by 800 kilograms a year.
Does the boiler require compartment ventilation?
The boiler does not require any air vents for cooling in the room in which it is installed or when installed in a cupboard or compartment. The minimum clearances for servicing must always be maintained.
Note: A cupboard or compartment used to enclose the boiler must be designed and constructed specifically for the purpose, i.e. comply with the Building Regulations.
Do Alpha boilers have a pump overrun feature?
When the boiler is not required to heat the system anymore, the pump will continue to run for 60 seconds, so heat can be dissipated around the system.
Do Alpha boilers have built-in frost protection?
Yes, Alpha boilers incorporate a built-in frost thermostat that automatically turns on the boiler and pump if the water in the boiler falls below 8°C, providing the electrical supply is on and the selector switch is set to position 1 or position 2. The boiler will operate until the water temperature in the system reaches approximately 40°C.
What do I do when the 'A' and 'B' lights on the boiler are flashing alternately?
This means that the system pressure is too low and you may see that the system pressure gauge indicates that the pressure in the system is below 1 bar and out of the green area.
To re-pressurise the system you will find a filling loop (metal braded flexible hose) on the underside or underneath the boiler with one or two tap connections at the either end of the filling loop.
The tap or taps should be opened a quarter of a turn and the water will start to refill the system (water should be heard filling the system). You should see the pressure gauge rise back up into the green area on the pressure gauge between 1 bar and 1.5 bar pressure.
Once the pressure gauge is in the green area turn the taps back to the off position and the water will stop filling the system. The lights should now stop flashing and the boiler will now operate. If the lights still flash, top up the system a little more but not over the green area.
If you do fill the system too much and the pressure gauge is over the green area, just bleed water from a radiator until the pressure on the gauge goes down into the green area.
What do the lights mean on the front of the boiler?
The lights on the boiler indicate various things. You can find out more by using our control panel troubleshooter