Search the forum,

22mm to combi boilers? 15mm no good?

Discuss 22mm to combi boilers? 15mm no good? in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Status
Not open for further replies.
M

Mobileghod

i know it says 22mm must be taken from the meter all the way to the boiler but obviously older boilers ive seen 15mm has been taken upto the boiler.

is it entirely incorrect say if you were doing a boiler swap combi for a combi to just extend the 15mm to the boiler or would i need to trace back and take 22mm all the way upto the boiler?

just a question as the boiler is n the landing and tge customer has new flooring down with the gas pipe going straight down under the boards???

cheers
 
not an expert but i blve the newer boilers require a higher gas flow to operate so 15mm pipework will obv not flow enough gas and the boiler i guess will under perform..only solution is too take new 22mm suplly outside and back in again
 
Last edited by a moderator:
The pipe size depends on the Kw of the boiler, how far away the meter is, how many bends, other appliances on the same pipe. If the gas pipe inlet on the boiler is 22mm then 22mm pipe is required all the way.
If the boiler is running on 15mm pipe. Check the inlet pressure on the boiler when the boiler is working full bore and any other appliances on the same pipe are running.
The pressure should not drop more than 1mbar than the same test taken at the meter
Low inlet pressure can lead to incomplete combustion, a rise in carbon monoxide and any warranty from the boiler co. being void!
Best practice is to allow for the pipe size upgrade in your Quote
 
i think the best bet is to have a proper look at the job and with a bit of luck 22mm isnt too far away.
sticking to the manufacturers instructions is number 1 priority i suppose.
think we best plan this out out thoroughly
the boiler will be 30kw only gas appliance in the house
cheers for the reply
 
30kw may even mean 28mm pipe from the meter then reduced at the boiler. Measure the distance, count the elbows, bends etc, check what else is on the pipe run. 15mm is never enough for 30kw, even if the meter was within touching distance
 
yeah thought as much. ill plan it out and trace pipework back to the meter. i havnt been round yet. the customer just mentioned that hes got the boiler looked at the instructions and found he needs 22mm to the boiler which i say is correct but theres only 15 on his old one...his main worry is obviously his flooring but im hoping his meter is outside and we can just run it up the wall and through to under the boiler..

so why would 15mm be ok for the older boiler, same kw? or wasnt it!?
half the time its the manfacturers covering there backs, but were best oversizing than undersizing for reasons u have mentioned.
 
If you don't know the answers to your own questions you are obviously not a registered installer. Remember you vistors are restricted when in prison if you kill somebody by illegally fitting a gas appliance. Good luck
 
plumbnuts said:
If you don't know the answers to your own questions you are obviously not a registered installer. Remember you vistors are restricted when in prison if you kill somebody by illegally fitting a gas appliance. Good luck
Click to expand...

what are you on mate get off your high horse, i was asking a valid question thats what this forum is all about... surely if you want to find out something you have to look into it and do a bit of research. i havnt installed anything and if i did it would be legal not illegal...... good luck pffft
 
Modern gas boilers with a 1:1 gas valve to not need 20mbar pressure at the burner.
one manufacture states in there manual that there boiler will give full output down to 14mbar, and can run on 15mm pipe work, but this goes against british standars that state you can not have more than a 1mbar pressure drop accross the pipe work.
This british standard is now out of date when it come to modern boilers but still needs to be worked to as gas fires and cooker ect still require 20mbar at the burner.
On tests, one boiler manufacture has seen full output at single figure pressures!!
Dan
 
The questions that you ask in relation to sizing gas pipes are as you state for a "Customers House". You dont have to be a "Pffft" to realise that you are on this forum to try to gain information to carry out illegal gas work. As I said good luck in prison if you kill somebody. Alternativly, just send me your CORGI number by private e-mail and I will appologise for being a "Pffft". I await no response.
 
We are, whilst being Corgi registered, at the mercy of non registered installers. Unfortunately its cheaper to not be corgi registered and do no retraining, get caught, maybe pay a fine if Corgi can get there act together. Corgi registration and the traing involved is not cheap. Thats why I don't do bathrooms!
I imagine the new Gas safe Register will be rubbing there hands together with glee come April!
Its hard to be tested by an inspector who has little knowledge or experience! Its even harder to think that Corgi registration can be done in 13 weeks training (BG from street to engineer). I have been doing this for 30 years and Still dont know it all.
In Mobileghods defence, Thre is no pipe sizing training in ACS as there was in Acops
There was a watchdog programme a while ago where a young Corgi registered Engineer, couldnt even work out how to get the lid off the boiler. There was an outcry as to how his work was done. But and its a BIG BUT. There is no training on individual boilers in ACS, or Acops before, or any other college course Including NVQ.
The lad needed experience with a variety of boilers with an older and more experienced engineer. Corgi is not the be all and end all of gas safety. The PArt P electrical qualification is even worse. In my course of 5 days which I had to do to get Part P. There were gas installers who somehow got through the course, with no prior Knowledge of electrical installation. Thats Scary. I am a qualified electrical engineer, and had to sit for a week watching disasters in the making as A gas installer magically became an electrical installer. I can speak as a Gas installer as I have TEC certs in Gas, and HAve all elements on my Corgi ID card. As a self employed Gas and Electrical consultant (and installer sometimes but my knees are knackered) It has cost me a fortune.
I am getting off my high horse now and apologise for talking off topic.
 
:) nice posts, like i say it was just a question, plumbnuts im still learning mate only been registered very recently it was just something i wanted to ask, simple as. ive not broken the law nor installed anything that will pose any risks, thats why im checking n questions like the above....awesome
 
well then i suggest you reference your pipe sizing guide and that will tell you. im surprised you are asking that question if you are registered, more-so if you are newly registered!!
 
Exactly my point CharterGas! I agree with your comments with the exception of learning gas pipe sizing on ACS. I agree that it is not included in a re assessment but it most definatly is included in the initial course/assessment. As I have said, I am willing to assist Mobileghod and explain the methods/reasoning behind gas pipe sizeing all he has to do is give me his CORGI number. I am not however, prepared to assist illegal gas workers who under cut RGI's due to no overheads, nor prepared to assist them with manslaughter.
Steve
 
have to say i have to,agree my son has paid for his training and cost best part of 4 grand but corgi seems very reluctant to get out there and police the installation/mtce gas area and as such illegal fitters who havnt been trained and certified are out there doing gas work
hopefully the gas safe register(daft name)are going to crack down on illegal gas work and yes in his training my son had to do pipe sizing and flow rates etc
 
its amazing i didn't think there was any corgi guys on this site i asked if any of you needed free help to gain experience and no reply's in a month! why do think that people undertake ilegal gas work? fit your boiler my friend do a gas tightness test before you start work to check for any existing leaks,and the same test after you have finished your gas work if your not 100% sure when commishining the boiler ie gas rate,burner pressure then get one of the many corgi guys which seem to be on this sight to do it for you for a fee. ps if you need a hand fitting it let me know,cos like your self mate i joint this forum for help......good luck mate.
 
mrgas said:
its amazing i didn't think there was any corgi guys on this site i asked if any of you needed free help to gain experience and no reply's in a month! why do think that people undertake ilegal gas work? fit your boiler my friend do a gas tightness test before you start work to check for any existing leaks,and the same test after you have finished your gas work if your not 100% sure when commishining the boiler ie gas rate,burner pressure then get one of the many corgi guys which seem to be on this sight to do it for you for a fee. ps if you need a hand fitting it let me know,cos like your self mate i joint this forum for help......good luck mate.
Click to expand...
thats the whole point dont fit the thing if
a/not corgi registered
b/sure of what your doing
why would any corgi guy come and sign off a boiler that if it goes pear shaped will have his name on it just for a backhander
do your training and read ur corgi books its good to ask questions but asking about whether 15mm gas pipe is good enough for a boiler with a 22mm connection would seem to point toward a complete lack of training and knowledge and not someone i would want doing any gas fitting in my house
 
Training and knowledge is not gained by illegal gas work as you can see by the first thread, reading and studying is a good start. It's strange, if you were asked to fly a Jumbo Jet solo, you would refuse due to lack of knowledge and understanding but most importantly fear for your own life. Work ilegally on gas and there is no fear as its not your life thats threatened. Strange eh!
 
This is an interesting post and one that I feel like saying to our government, can you see what we were saying to you when you foolhardily introduced this mad scheme. I remember lobbying labour's elf n safety MP Angela Eagle. So my question was to her, so what will stop any individual doing a course, such as carpenters to become gas engineers? No, no I was assured only like minded tradesmen will be able to do the course, so a kitchen fitter would only be able to do fitting of gas hobs for instance? I lost the plot with this absurd system when I did my last ACOPs course with a carpenter that did ALL elements of the course. He was now as qualified as me and in the eyes of the law a fully fledged gas fitter and service engineer. Make no mistake there must be a scheme in the interest of gas safety. But not the way they have gone about it. I remember going to a water heater once, that had be allegedly maintained by a newly qualified gas person, to find the pilot light 30cm long and the heater sooted up. The customer had paid well over £200 to have work done on this heater and I corrected the faults for under £45 including parts. They can change gas legislation as much as they like, but until the government realizes that there is no substitute for proper apprenticeships, then sadly we will always be doomed. What ever happened to the 2.5% CITB used to take of my profits to put back into apprenticeships? I think I have a legitimate claim for my money back?????

Bagsy
 
whats the craic,:D
my bubble i think has just been burst ...:eek::eek::eek:
i thought that the qualified gas engineers in the uk were all clever/intelligent ,experienced and highly tested tradesmen.now it seems that there are carpenters and other non related people passing the courses.jesus lads, the reason i came on here is because i thought the english lads were well up on things. just to say i'm pretty disapointed in hearing this . p s . i know little about gas and not intending to knock the good guys on here. in ireland u must b a qualified propper plumber ,with papers ,to do gas.there are no quick courses here on anything, apart from flower arranging and origammi.
not saying the trades in ireland are better, believe u me there are more cowboys here than hollywood in the 50's.
a disapointed,:(:D
buffy
 
Just doing pipe sizing in first week of CCN course. Its fairly straightforward, just use the tables, a tape measure and the rating of appliances to be installed. Not rocket science. I strongly suspect the real benefits of experience would be realised on "real installations" once the parameters have been established. I.e. choosing the most common sense way to run the pipes through the building to the appliances, fortunately having been a plumber for over 4 years I've got a little bit of that, one thing I am picking up is that you have to consider future developments, i.e sizing for a conventional hob when in the future that could be changed for a massive range type of thing or one of those hobs with a huge wok burner on it. All interesting stuff.
 
I think we will find that Gas safe register will be the same toothless high priced entity that Corgi was/is.

Corgi changed their policies a few years ago to become a profit making organisation at the expense of course of Gas engineers.
Gas register Start as they mean to go on.....Profit!
 
I cant understand why any corgi registered installer would want to give out free advice to people who shouldnt be working with gas , we pay alot of money in assesments and to corgi to show we are competent and able to work out gas rates , pipe sizes etc.. I am going to have a look to see if theres a pilots forum because i fancy flying planes and want some tips , got to be cheaper than getting a pilots licence !
 
Fatoftheland - I agree give people that are newly qualified a helping hand. You need to read the thread! He refers to working at "Customers house" and doesn't know the basics. As previously stated, if newly qualified he would know that the old boiler with the gas pipe run in 15mm is not the same output as the new boiler. I have asked him to send me his Corgi number by private email and then I will be willing to assist in anway I can. But as said, I am not prepared to assist illegal gas workers to undercut registered installers who have the obvious overheads. Gas pipe sizing is basic knowledge, particually if you are newly qualified!
Steve
 
Only read first and last page and really only want to say that if you don't know the basics of pipe sizing and the importance of getting it right you probably haven't got a clue about any of the real safety issues involved when installing heating (gas) appliances and therefore should not be doing the Job.
As for bagsy I would say to him - If a young bloke leaves school and does an apprenticeship in plumbing & gas and then realises after years of work that he has really hated the whole thing from the outset but stuck it out on his fathers advice and encouragement. But now says enough is enough and decides its time to get out and experience something else. Is it too late for this person now? - Is he a plumber for life or is he aloud to re-train and possibly spend the rest of life doing something he might enjoy a bit more?
 
I didnt know everything when I first started , and I probably dont now !But before I was let loose on my own in customers houses I worked under people who did know everything and were there to assist me , but I would have got a proper bXXXXXXXing if I didnt know how to gas rate an appliance and size the pipework correctly especially after just learning it all in college.
 
there is a chart in the gas core book to work out what size pipework you need to avoid a drop of over 1mb drop over the carcass .

i havent passed the gas corse that long ago and wanted to know if every one knew if you had to have esentrial elerictrics to use a multi meter on a boiler
 
Last edited by a moderator:
feltham said:
there is a chart in the gas core book to work out what size pipework you need to avoid a drop of over 1mb drop over the carcass .

i havent passed the gas corse that long ago and wanted to know if every one knew if you had to have esentrial elerictrics to use a multi meter on a boiler
Click to expand...


Good question! I doubt it. You'll just be checking to see if somethings shorted out I guess? A lot of heating engineers are becoming Part P registered now though.
 
Last edited:
plumbnuts, your right but calm down!

dan mekrl, manufactures instructions are to be followed over and above gas regulations, unless they contravene british standards. to contravene the standards the present instalation would have to fail them. our gas regs are not backdated which means his instalation under test might possibly be n.c.s
the british standards are never out of date, they are just ammended ( their rules not mine)

shaun

nor do i approve of unregistered/qualified people working on gas stuff they dont understand.
xx
 
Last edited by a moderator:
Good practice to over size the guvoner and gas valve will work for you never under size

thats why the regs are there bruv always over size if any thing its good practice
 
Last edited by a moderator:
Did you know that all condensing boiler love bigger size of gas pipes? 22mm ,but if the gas meter far away you need to re-size the gas pipes from 28mm to 22mm straight. then check the inlet gas pressure.I beat you if not enough gas supply You are in trouble... To be honest ask extra payment to your client and how ?and we need to be done. if doent agree,well, dont risk your Corgi I.D...if happen They will call a Corgi inspection or gas safety inspector to check the gas supply..Now You will recieve a letter to the Corgi..asking you to re-done or test....You must prove to them that is ok..if not..You will pay all the cost..Cover your pocket....I this days..Be clever..dont risk it..I learn this from my work for many times

Cheeers,
vdc
 
Sorry mate - "the dogs" went on the first of April!

End of the day if your installing modern HE boilers you should be working out your pipe sizes properly and charging for upgrading gas supply. A 40kw combi will work on 22mm but really you should be putting in 28mm, especially with consideration to other appliances -e.g. cooker ranges, what happens when both are in full use and boiler at max gas rate for hot water and the fires on in the living room also? A lot of these boilers will still work if minimum pressure there as self governing - but why turn a 40kw boiler into a 30kw by not doing your homework?
 
Last edited by a moderator:
condensing or not makes no difference if you want 30kw of heat you need to burn enough gas to provide it to get enough gas you need a pipe size that will provide it at a given preasure
can anyone wiser than me explain why we deliver gas to our appliance at such low preasure if we had more preasure we could use much smaller piework
 
New posts
Status
Not open for further replies.

Reply to 22mm to combi boilers? 15mm no good? in the Plumbing Jobs | The Job-board area at PlumbersForums.net

Similar plumbing topics

W
Outdoor Tap at Porch
Hi, basic question, any insight much appreciated. Looking to have an outdoor tap in my front porch fed from 15mm pex coming up from suspended floor. Pic 1 is inside porch, pex temporarily clipped to give an idea of pipe placement (ignore shoddy blockwork of booted cowboy builder!), Pic 2 is...
Replies
6
Views
219
Dave Moore
D
A
copper vs pushfit pipes
Copper pipes, I think its fair to say, is not what it used to be, the copper is getting thin while the cost is going up. Meanwhile, plastic Pushfit seems to be getting better and better, cost and convenience was always better, but now the quality is to, have we reached a stage where plastic will...
Replies
2
Views
227
Chuck
C
johndave
Outdoor stopcock doesn't fully close
Hi all I'm hoping someone can shine a light on this for me Since our stop tap on the pavement has now been filled with sand for whatever reason, we are relying on our property fitted stopcock (this is outside on our garage wall) Unfortunately turning this to the closed position only reduces...
Replies
3
Views
233
exedon2
exedon2
C
Mixer bar fitting solutions?
The fittings below are for a mixer bar attached to a self contained shower. i.e not a wall. The attaching screws have snapped. I could get two new brackets, dismantle that existing one and start again or I could try and re attach via those screws, removing the broken ones from the plate and wall...
Replies
1
Views
181
SimonG
SimonG
P
Repeated Airlock in Bathroom
Hi, Can anyone advise as to why the cold water to my bathroom keeps airlocking? This originally happened about 12 months ago and has happened 3-4 times since. It’s an upstairs bathroom, fed from a tank in the attic. The tank is about 8 Meters away and feeds a bath, sink and toilet. The tank...
Replies
9
Views
308
Chuck
C
Creating content since 2001. Untold Media.

Newest Plumbing Threads

Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock