The Ultimate boiler installation checklist!


So you’ve decided to put your old boiler out of its misery and replace it with a new shiny one, gas boilers are vitally important to our lives they keep ourselves and our families warm on cold nights and provide us with that lovely hot bath after a hard days work. However the old one did that and now you have to cancel that cruise you’ve always wanted and pay for a new boiler instead. Even though it’s so vitally important to you and your family and you may have had to cancel that dream holiday, how much do you know about what’s involved? Has it been fitted correctly and will my warranty be valid if it isn’t? And most importantly is my new boiler safe?  You would research the death out of the nighlife, the beach, the hotel etc etc if you were spending 2k on a holiday, but many don’t when they spend 2k on something as important as a new boiler. You trust the word of the installer and 90% of the time that’s great but make sure you don’t become one of the many customers we visit across the North East Who’s new boilers aren’t safe, compliant or functioning properly.


Follow our checklist below to ensure you’re getting a “proper job”:

(or call Gas Angel for a guaranteed perfect job )


  1. Location

Boilers can be located pretty much anywhere providing they have the clearances this is so the case can be removed for servicing and so repairs can be carried out. If the clearances aren’t met then a manufacturer can refuse to repair it. Also bear in mind that if you have a combi boiler 5 copper pipes and one plastic pipe will need to go in to the bottom of the boiler if it’s a regular boiler then you will need just 3 copper and 1 plastic pipe. Also consider the noise most are very quiet nowadays but it’s still worth considering. Also Remember you’re the one who’s going to have to look at it every day so it’s probably not a good idea to put it above the TV. The final thing to consider is the flue, this exits the top of the boiler and either goes horizontally or vertically and then goes through a hole in the wall or roof to the outside.


  1. Flue

The Flue emits a plume (cloud of smoke) out of the terminal (bit on the end) so remember this will be visible from a window inside your house or could blow in your face if you’re outside having BBQ. The terminal MUST be 300mm from a window, door airbrick or pretty much anything that allows air to travel from inside to outside. You can use plume kits which can divert the fumes if you/your installer thinks it will be a problem or if it’s a safety issue.


  1. Gas pipe

Quite simply if your gas pipe is too small then your boiler wont function properly and will be potentially unsafe. As a rule of thumb you shouldn’t have any 15mm pipe from your gas meter to your boiler it should all be 22mm, if you have a boiler above 36kw then you may need some 28mm or at least some of the pipe will need upgrading. The need to upgrade gas pipes Is very common so make sure you ask your installer whether its needed as we see far too many new installations piped in 15mm.


  1. Pipe clips

Make sure the pipes are clipped (every 1 metre as a guide) otherwise they could become noisy or be unsecure.


  1. Condensate pipe

The pipe that runs to a drain either internally or externally. Internally it should be after any waste traps and is normally “tapped in” to an existing waste pipe. Externally it should be 32mm or above to avoid freezing and terminate below and drain grills or covers. Another option is to use a pump or soakaway (buried in soil) unless you’re using a pump then the pipe MUST slope down away from the boiler, if not the condensate could back up in to the boiler and completely destroy your main heat exchanger meaning you will need a new boiler in 6 – 12 months. A good slope also reduces the chance of freezing if external.


  1. Flushing/filter

If you replace the boiler but don’t flush the system you’re essentially putting a 10 minute old boiler on to a 50 year old system. All of the sludge and corrosion built up over the years will travel straight through your new boiler clogging up everything in its path. Manufacturers will not replace sludge damaged parts. Make sure the system is thoroughly flushed out with chemicals and inhibitor (a chemical that massively slows down any build up of sludge) Is applied once the system is re-filled. Finally make sure a filter is installed on your return pipe this not only collects the sludge but stops any of it from entering your boiler.


  1. Documents

Once your boiler is commissioned by your installer, you must ensure he/she registers your warranty (he/she has 30 days to do this) and that they’ve registered your new installation with gas safe you need this certificate in case you ever want to sell your house.


I hope you’ve found this article useful, and if you would like any further advise or if you would like us to give you a free quote for a new boiler installation, then please do not hesitate to get in touch.



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