It's human nature to want to know how much you're going to spend. My aim here is to outline the main factors when considering a new combination boiler. Please keep in mind that the prices below are there to give you a rough idea of the cost of materials and do not include labour costs.
a) The make of the boiler
I put boiler manufacturers into three broad categories:
Of course, the above categorisation is very much a generalisation. I am not here making any judgement on quality. It's much like car brands I suppose. For example a budget brand could be Dacia, mid-range might be Ford, and top-end might be Mercedes. It does not mean that just because one is less expensive than the other that it is any less reliable or doesn't do the job that is required of it. So cost wise you can get a Heatline combi boiler for less than £500, Baxi combi boilers start at around £600, and Worcester combi's start at around £900.
b) The size (kw rating) of the boiler
The size of your boiler in terms of KW rating is a really important factor. This will be determined by two factors:
This second factor is usually the most important. The greater your hot water demand the greater your boiler KW rating should be. You will get a better flow from your mixer shower and a quicker filling bath with a higher rated boiler. A word of warning here though. Because combi boilers rely on heating your incoming cold mains water supply, your hot water flow from your boiler will be governed by this. So if your cold main only supplies 10 litres per minute of cold water to your boiler you won't get any more than 10 litres per minute of hot water out of your boiler. A typical 40KW combi boiler can provide over 16 litres per minute of hot water but would really be wasted if your incoming mains was only 10 litres per minute. It is really important that the size of the boiler you get is suitable for you and your property.
c) The flue
The cost of the flue (chimney) will depend on where your boiler is located and where the flue terminates. If your flue is a standard horizontal one that goes straight through the wall behind (or to the side) of the boiler then your looking at between £50 and £100 (dependant on make). If your boiler is further away from the outside wall then you are going to need extension pieces and possibly elbows, offsets and brackets. All of which add to costs.
If your flue needs to terminate vertically i.e. through the roof, then this is most likely going to increase the cost (not only for the flue itself but also as the installer will need to access the roof).
Because condensing boilers now plume (looks like steam coming from the flue), a 'plume kit' may also need to be fitted to direct this 'plume' away from windows, passage ways or even a neighbour's boundary.
If your flue is less than 2 meters above ground level or is a place where it could potentially get blocked or damaged the a terminal guard will need to be fitted.
d) Gas pipework
Gas pipework to a new combi boiler will need to be a minimum of 22mm, and may even need to be 28mm depending on the KW rating of your boiler and how far it is from the gas meter. Keep in mind that many old boilers were installed using only 15mm pipe which will need upgrading, and could add quite substantially to the installation cost.
e) Condensate pipework
New boilers produce condensation which needs to be disposed of. This is done be running plastic pipe from your boiler to a drain (usually and preferably to a waste pipe inside your property i.e. to your kitchen sink waste pipe). Sometimes access to the waste may not be possible. For example if your boiler is located on the opposite side of the house to the kitchen or bathroom then a drain may not be easily accessible. In these instances a soakway may need to be installed, or sometimes a pump may be needed to pump the condensate away. Again, if necessary, these are going to add to your installation cost.
f) Cleaning the central heating system
As a minimum your system will need a chemical cleaner added and a good flushing through. This is a minimum requirement of all new boiler installations and should already be part of your quote. However, if you have an old system that has never been treated with inhibitor and your radiators have been slow to heat up or have coldspots, then you could heave problems with sludge build up. If this is the case then a powerflush may be necessary to thoroughly clean the system and prevent future problems. If done properly a powerflush can take up to a day and add upwards of £250 (depending on the size of your system) to your final bill.
As an addition, a good quality central heating filter should also be fitted to maintain the water quality in your system. These retail at around £100.
g) System controls
If your radiators don't have Thermostatic Radiator Valves (TRV's) already fitted then these will need adding and cost between £10 and £20 each.
You will also need a room thermostat and separate programmer, or alternatively a programmable thermostat. Consider also if you want to connect your heating to wifi so you can control it remotely on your mobile phone. Either way you are looking at between £50 and £200.
What I have tried to do here is help you appreciate all the different elements that need to be taken into account when considering a new combi boiler installation. The above factors need to be considered when comparing quotes. Remember, labour costs will need to be factored in. This information will hopefully assist you in making an informed choice.
When you get a quote these are all things that the installer will take into account and advise you on. This is just to give you a 'heads-up' so you are prepared before a site visit.
DOES MY SYSTEM NEED POWERFLUSHING?
Some manufacturer's now offer 12 year warranties on certain boiler models. This is pretty incredible when you consider that a boiler is something that is in use more or less every day of the year, and during cold snaps can be on continuously for log stretches of time.
Most of us never read the terms and conditions when it comes to warranties (not just boilers!). It is not as simple as just getting your boiler installed and then expecting the manufacturer to honour the warranty.
If you are getting a new boiler then you need to make sure the installation meets the requirements below (as a minimum).
If your installation does not meet the criteria above then the manufacturer could very well refuse to honour the warranty.
Any of the symptoms above could indicate that your central heating system has circulation and flow problems due to the formation of rust, sludge and scale deposits.
A power flush machine is connected to your central heating pipework and a chemical cleaner is added. The water is then pumped around your system to loosen and mobilise harmful corrosion deposits like rust, magnetite and scale. Once loosened, the unwanted debris and cleaning chemicals are purged from the system with clean water. At the end of the process your system is filled with clean water and central heating inhibitor which will help reduce future corrosion.
I would not fit a new boiler without a system filter. There are four main reasons why a central heating filter is a good idea:
From experience I can tell you that these really do work (see photo left). When they are cleaned annually they give a good indication of how clean (or not) the system is.
Most filters are pretty good at catching magnetic particles. However, it is worth remembering that your system may also contain none magnetic sludge. This is why it is so important to ensure the system is thoroughly flushed and inhibitor added before a filter is installed.
Is a filter worth fitting on an existing boiler installation? Yes, provided the system has been flushed beforehand. Remember, a filter is not there to clean a system that is already dirty. A filter is fitted (and inhibitor added) to maintain the cleanliness of a system be helping prevent the build up of dirt and debris over time.
Before the service begins I always ask the customer if they have had any issues with the boiler and heating system i.e. have all the radiators been heating up sufficiently? Have they had to reset the boiler recently? Has the boiler displayed any fault codes?
I also ask if the customer has the boiler manufacturers' instructions at hand so that the Benchmark section can be filled in at the end of the service.
I then ensure that all gas appliances are turned off before carrying out a gas tightness test at the gas meter. This ensures that there are no gas leaks on the entire system. Whilst at the meter I can also check that the gas isolator operates correctly, the gas pressures are correct, and there is electrical bonding present.
I would then briefly operate the boiler and make a visual inspection to ensure that the boiler and flue has been installed correctly to the manufacturers' specification. This is also a good time to check the system pressure and see if there are any tell tale signs that water has been recently discharging from the pressure relief valve.
The boiler is now safely isolated from the electricity and gas before the casing is removed. The internal components are now inspected for any signs of distress i.e. leaking or corrosion.
Following the manufacturer's instructions the boiler and its components are now cleaned i.e. primary heat exchanger, burner, and condensate trap.
It is worth mentioning here that the extent of the servicing will vary based on manufacturer and also the age of the boiler. Seals/gaskets might also need replacing at this stage (the customer will be advised beforehand).
Once the boiler is reassembled a number of test are carried out. These include checking for gas leaks within the boiler, measuring the gas pressure, the gas rate and also analysing the flue gases. Any necessary adjustments can now be made so the boiler operates safely and efficiently.
Once all the final checks are completed the paperwork can be completed.
If you have a central heating filter fitted then I would also clean this out. The contents of the filter would also give a good indication of the cleanliness of the central heating system.
The condensate pipe from your boiler is a white (can be grey or black) plastic pipe that comes out the bottom of your boiler. If this pipe runs outside there is a chance that the condensate water in it could freeze and block it up. The condensate will 'back up' prevent your boiler operating, and your boiler may show an error code and possibly start making a gurgling sound.
Steps to defrost your condensate pipe:
Remember, this is only a short term solution and it might not be long before you have to repeat the process!
If the condensate pipe from your boiler runs outside and is susceptible to freezing there are a couple of things you can do to reduce the risk:
TRV's or Thermostatic Radiator Valves allow you to control the temperature in each of the rooms in your home.
What do they do?
TRV's stop the flower of water through the radiators they are attached to when the room temperature goes above a certain setting. They do this by sensing the air temperature next to the radiator.
Contrary to popular belief, the numbers on the TRV do not indictate how hot the radiator gets, but rather at what room temperature the radiator will switch off. For example, if you set the TRV to number five, the radiator will be stay on until the room gets to a high temperature and then it will switch off. Whereas if you set it to number one it will switch off once the room is at a much lower temperature.
Once the room is at the desired temperature the TRV will stop the flow of water to the radiator.
How do they work?
The TRV is made up of two parts – the valve head and the valve body. When the room temperature changes, a capsule in the valve head contracts or expands, which moves a pin in the valve body causing it to open or close. If the room is above the desired temperature the valve will close, causing water to stop flowing to the radiator, and when the TRV detects that the room has dropped below the desired temperature, the valve opens and water flows to the radiator once more.
Should I have TRV's fitted?
TRVs are useful if you want a particular room to be set at a higher or lower temperature than the rest of the house, as they do not control the boiler but just that one radiator.
For example, if you don’t use one room much, you might want to set it at a lower temperature than other rooms as it doesn’t matter if that room is a little cooler. Or you might want to set a lower temperature if a room is heated through other means – for example through electrical appliances, fires, or the sun coming through the windows. Other rooms where you might want a different temperature include conservatories or utility rooms, where the temperature is often different to the rest of the house. They are also great to have in bedrooms where you want to keep a nice constant temperature when you are asleep.
If your central heating does not already have TRVs fitted, installing these may be a good way to save money and energy when heating your home.
Most Thermostatic Radiator Valves (TRV's) have numbers from 0 to 5 on their plastic head.
The numbers on the TRV do not dictate how hot the radiator gets, but rather at what room temperature the radiator will switch off.
The temperature range for each number varies slightly depending on the make of the valve. As a general rule the following temperature ranges apply:
setting 0 = OFF
setting 1 = 11 to 13 degrees C
setting 2 = 15 to 17 degrees C
setting 3 = 19 to 21 degrees C
setting 4 = 23 to 25 degrees C
setting 5 = 27 to 29 degrees C
Many TRV's also have a STAR (*) setting which is a frost protection setting.
Some also come with an energy saving button so you can ensure it is set at the most economic temperature. You can even get electronic TRVs which use batteries and electronic thermostats to monitor and adjust the temperature of the room, and display the temperature digitally.
(from outside the property)
Every WRAS Approved product comes with a WRAS Approved logo (pictured).
Products that are WRAS Approved, such as valves, boilers and showers undergo mechanical and water quality testing. The testing is to make sure the fittings prevent waste, misuse and undue consumption of water. Most importantly they ensure fittings prevent the contamination of drinking water.
Non-metallic materials and components such as rubber sheet material, ‘O’ rings and spacers undergo testing only for their effects on water quality. This type of approval demonstrates that the component does not contaminate the water.
WRAS approval itself is a voluntary scheme. So while you would expect manufacturers to have products WRAS approved – they are are under no legal obligation to do so.
There are a few reasons why you may be hearing noises coming from your pipes. These noises don’t necessarily indicate that there is anything seriously wrong, and the pipes can often be easily quietened. Here are three possible causes of noisy plumbing in your home:
1. Water Hammer
Water hammers occur when water is suddenly forced to change direction. It is most common when you use appliances that require a lot of water in order to function such as toilets and dishwashers. These appliances often take in a high water flow and then suddenly shut it off.
It can also occur when you turn off a tap in your home. This is particularly true with taps that incorporate ceramic disk valves (rather than the more traditional rubber washer, compression style valves) as the flow of water is cut off abruptly. When you turn off the tap, the valves close up and the water pipes are suddenly deprived of air. Air is important for cushioning the pressured water in the pipes. If the air is suddenly reduced the pipes cannot control the pressure and a water hammer can occur.
Ways to reduce water hammer
2. Loose Water Pipes
If pipes aren’t securely clipped they can move around when water is flowing through them. This is why these loud plumbing noises are common in older houses.
The way to solve this issue is to locate the loose pipes (unfortunately these could be under floorboards or behind walls) and to clip them properly. Again, it might be worth reducing the water flow slightly at your stopcock to see if that helps.
3. High Water Pressure
Your plumbing can get noisy when water is pushed into your appliances at too high a pressure.This doesn’t just make an annoying noise – it can also cause problems with your appliance’s internal components.
If your water pressure is on the high side (can be checked with a gauge) then it might be worth getting a pressure regulator or pressure reducing valve fitted.
reduce water hammer
You will need a Gas Safe Registered engineer to: