What do I do if the top of radiator is not getting hot when the bottom does?
This is normally due to a collection of air in the radiator. This can usually be cured by bleeding the radiator using a key. Have a cloth ready to catch the drips as the water is usually dirty. Bear in mind that on a sealed system the pressure will need to be topped up.

What are the benefits of radiator thermostats?
The use of Thermostatic Radiator Valves prevents individual rooms being 'overheated'. Without TRVs the only temperature monitoring and control is done by a room thermostat; this covers the whole house rather than an individual room. Some rooms tend to warm up quicker than others; therefore a TRV can maintain comfort while potentially aiding economy. The new building regulations strongly advise that on new installations and significant upgrades.

My central heating has started coming on with my hot water (whether I like it or not).
This is usually down to a failed motorised valve (on a conventional cylinder/boiler system).
My combination boiler will only deliver hot water when the central heating is on! This is usually a fault within the diverter valve mechanism; this is not a DIY job.

What to do if water is leaking from the cylinder?
Copper water cylinders have a finite lifespan; if the water is leaking from the bottom of the cylinder it is prudent to take immediate steps to replace it, as the situation could rapidly get worse. If the water is leaking from a pipe union to the cylinder, this can normally be fixed by remaking the joint.

What setting should the boiler be set to, different for summer/winter?
For conventional boilers, during the winter the boiler thermostat should be set higher than the summer. It's best not to run the boiler indefinitely on the highest setting.

How long will an average boiler last?
This very much depends on the type of boiler chosen, and the quality of the system it is connected to. It is usually worth specifying the best boiler you can afford, they are not all the same inside

Type of boiler
Combination boilers offer instantaneous domestic hot water as well as central heating, and as such are very convenient. However, their design is more complex than conventional boilers and the lifespan is typically 6-12 years, depending on the build quality & hardness of your water. Conventional cast iron boilers have a longer life, 20 years is not uncommon.

Should central heating be used occasionally in summer?
Yes, if the system is run occasionally it will prolong the life of certain components, including the pump. Some combination boilers automatically run the pump & diverter valve periodically during periods of inactivity to help extend their life.

What affect does water metering have on costs?
If you prefer baths to showers, and water the garden regularly, a water meter may prove to be the more expensive option.

How often can radiators be painted and what impact will it have on performance?
It's best to paint radiators in 'radiator enamel' which is less likely to discolour over time with heat. Most new radiators already come with a gloss white finish. Painting will have very little effect on performance, as most heat is by convection rather than radiation.

Can I paint copper pipes?
Yes you can, but bare/new copper should be first lightly abraded with emery cloth or wire wool, and then wiped with white spirit to remove any preservative/grease.

Does insulation on the hot water tank reduce bills?
Yes

What does it mean when pump is whining loudly?
It can mean that the bearings are badly worn, there is an obstruction in the flow of water, or there is no water in the system.

Is it cheaper to use a gas boiler as opposed to the immersion heater?
Yes, in almost all cases.

My hot water does not get warm enough
On a Combination Boiler this is usually due to sludge and scale build up in the DHW heat exchanger. This is not a DIY job to rectify, and can be indicative of more far reaching corrosion problems in the system. In a normal, cylinder fed system the 'cylinder stat' could be set too low. During winter months, the boiler thermostat will need to be set nearer the maximum than in summer, due to the extra demands made by the central heating.

What are the differences between 'combination' and 'conventional' boilers?
A combination boiler is where the boiler handles central heating and instantaneous hot water requirements without needing external tanks or cylinders. Conventional boilers are merely a gas/water heat exchanger, the water from which is then routed using external controls to radiators and hot water heat exchangers (e.g. a cylinder).

What is a condensing boiler?
Conventional boilers emit hot exhaust gases from the flue when they are operating. A condensing boiler transfers much of this wasted heat to the water in the boiler, before it reaches the flue outlet. An excellent idea which saves on fuel use therefore operating costs. During normal operation, condensing boilers lower the temperature of their exhaust gases below 100 degrees, at which point plumes of water vapour can be seen coming from the flue outside. For this reason condensing boiler flues should be sited sensitively.

Whilst there are gas consumption savings to be made from a condensing boiler, their actual efficiency is dependent upon the system design of the heating circuit. A condensing boiler is more complex to manufacture and this is reflected in the higher purchase price.