Lakewood House, 50 Hiltingbury Road, Chandlers Ford, Hampshire, SO53 5SS

Frequently Asked Questions

At Gair Gas Ltd, we understand that a reliable boiler is at the heart of every home and we are committed to helping you install, maintain and get the most from your heating system. To help you along the way we've put together this list of frequently asked questions..

How often does a boiler need servicing?

You should have your boiler serviced annually make sure your boiler is running as efficiently as possible. A boiler which isn't working to full efficiency is sure to be costing you money on your fuel bill, so it's likely that the cost of a service will be quickly offset. Gas leaks are very rare in boilers but can be extremely dangerous. Regular services will ensure that your boiler is working safely, as well as effectively. The peace of mind that comes with the knowledge that your boiler is safe is always well worth.

What type of boiler should I choose?

When choosing a new boiler there are several things to consider. A condensing boiler makes more of the energy it runs on by using heat normally expelled through the flue. By converting over 90% of the fuel used (rather than just 50% in the case of some old boilers), a condensing boiler makes your fuel go further. Therefore, a condensing boiler can help to save you money and reduce your carbon footprint.

Combi Boiler

Combi is short for 'combination'. It refers to the way this type of system serves as both a central heating boiler and a hot water heater. That means there's no need for a water tank as hot water is provided on demand. As well as saving the space normally taken up by a water tank (in the loft or airing cupboard), a combi boiler saves on hot water costs as well as giving you hot water at mains pressure.

Regular Boiler

This typically forms part of a conventional heating system, and is linked to a series of water tanks that feed the boiler and radiators. Storing hot water is key to this system, so unlike a combi, a plentiful supply of hot water is always available. Space in the loft and airing cupboard is required for tanks.

System Boiler

Like a regular system, this uses stored hot water. But because the water is pumped from the boiler straight to the radiators and hot water tank, it's a faster, more economical system. What's more, many of the components of the system are built-in, making it easier, quicker and more affordable to install. Gair gas can provide you with free advice on which boiler would be best for you.

How do I bleed a radiator?

Trapped air or gas prevents hot water from heating your radiator fully. The good news is, bleeding radiators is a simple job that you can do yourself, and it can make a real difference to how energy-efficient the heating in your home is.

While this isn't a hard thing to do, please follow these instructions with caution. If you don't feel confident about what you're doing, stop and get advice from a qualified heating engineer.

Step 1 Turn on the heating so that all radiators in your home come on - you may need to turn up the temperature on your thermostat and individual radiator temperature controls to make sure they all come on. Once your radiators are all hot, go and check each one individually to see if all parts of the radiator are warming up.

Cool spots, particularly towards the top of the radiator, mean that there could be air or gas trapped and therefore you'll need to bleed that radiator.

Step 2 Before you bleed any radiators make sure your central heating is switched off. This is reversing the process identified in step one and will allow you to handle the radiators without burning yourself or soaking your floor.

Bleeding radiators usually requires a radiator key, but with more modern radiators you can use a flat-blade screwdriver. You can buy a radiator key from any DIY store

At the top of the radiator at one end there will be a valve. You can attach the radiator key to the square bit in the centre or put the end of the screwdriver into the groove. Hold the key or screwdriver with a cloth, and have another cloth ready to catch any drips, then slowly turn the radiator key or screwdriver anti-clockwise - if gas is escaping you'll hear a hissing sound.

Once there is no more gas, liquid will come out and the valve will need to be closed quickly. With the more modern screwdriver operated escape valve, liquid is likely to emerge as a jet rather than a dribble.

Step 3 Check the pressure by having a look at the gauge on your boiler. If the pressure is too low, you'll need to 'top up'. You can do this using the lever or tap on your boiler, known as the filling loop.

Afterwards, you may want to run another 'hot test' to check that your efforts have been successful. Simply turn your heating on, wait for all the radiators to heat up and check for any cool spots. If you have any problems feel free to contact Gair Gas for advice

What should I do it my boiler has no pressure?

A loss of water pressure is a good indicator of some common issues that arise with boilers. Low pressure is relatively easy to diagnose, as most boilers have a builtin pressure gauge. Sometimes, it's possible to correct water pressure yourself

A number of things can cause pressure to drop. It may be that there is a leak somewhere in your boiler system. Or, if you bled your radiators recently, it may be that pressure was lost then.

Each boiler will come with specific instructions about its pressure system. Check your user manual to see if you can re-pressurise your boiler yourself. You may also find instructions on the rear of your boiler control panel. However, if your boiler panel needs tools to remove it, don't touch it - book an engineer.

How to bleed a radiator

This video demonstrates how to bleed a radiator, in order to release built up air and solve heating problems such as a 'gurgling' sound and cold radiator tops.

How to Repressurise a Heating System with an Internal Filling Key

This video shows you how to repressurise your heating system using your Greenstar gas boiler's internal filling key.

  • worcester
  • gas_safe
  • buy_with
  • Visa Cards
  • We take all the major credit cards*

    *We do not accept American Express or Diners cards.

    *3% Charge on Credit Cards