fitting a system

[dave knight]

hi all. i'm a newly qualified plum bum, although not fully (as i'm doing a fast track course, and yes, you can bad mouth it as much as you like lol).
my landlord has asked if i can fit central heating for him in the little cottage that we rent. i've been planning it out and think i have most aspects covered, but just a few questions to ask of you more experienced people.

the house currently has a multi point instantaneous water heater, as all heating is electric and gas heaters. the mains pressure is really good so i was thinking of a combi boiler (as also, there isnt the room for a cylinder etc). worc/bosch have been recommended as a good make and after a little searching decided upon a green star 28i junior. as its only a 2 bed prop, there will be 5 rads on the system. the longest run to a rad will be about 14m from boiler.

basically, any advice you time served veterans can give would be nice, and also things like pipe size?, are trvs necessary?, will rads need balancing on a combi?, and anything else you guys may have think ive overlooked.

appreciate your time

ps. i am aware i cant touch the gas side of things.

 

[Toddyplumb]

Which fast track course are you on ?

 

[Mbear]

Gas pipe sizing is important, ie most boilers require 22mm gas pipe supply however some can be fed in 15mm(basically read instructions)

As far as boiler and pipe sizing goes I'd prob fit a potterton promax 24kw combi. For a 2bed u don't really need added expense of a w/Bosch IMHO. Run the ch pipes in 22mm for as long as space and access will allow, then use 22-10mm manifolds and run to the rads. Not much balancing reqd on this size system tbh. Remember you've got a condensate pipe to fit, u need to decide hw this will run and if it can't be run at a downward gradient at all times u may need to plumb and wire in a condensate pump. Controls you'll need, timer and room stat to be wired in along with trvs on all rads bar 1(bypass).

If this is ur 1st time I'd maybe get experienced help in for this one. Once you've done ur own house with an experienced guy you'll have no probs doing it urself from then on.

 

[Chrisgy]

TRVs are required on all rads in bedrooms, but I always fit on every rad, leaving out one rad with 2 lockshields, usually in the hallway where the room stat goes. Don't do 22 - 10mm, do 22mm from the boiler and split off in 15mm to rads, no need to use loads of 22mm either.

Balancing will be fine just leave all lockshields open

 

[Mbear]

TRVs are required on all rads in bedrooms, but I always fit on every rad, leaving out one rad with 2 lockshields, usually in the hallway where the room stat goes. Don't do 22 - 10mm, do 22mm from the boiler and split off in 15mm to rads, no need to use loads of 22mm either.

Balancing will be fine just leave all lockshields open

There's nothing wrong with 10mm pipe for an install of this size. It increases speed and eases fitting with absolutely no detriment to flow rates to rads etc. My house is a 2bedroom '4 in a block' house with 1 bathroom and a kitchen, I've ran 22mm pipe into my loft down through my hall cupboard into the hall and split into 10mm manifolds to 5rads. My system works spot on.

 

[doitmyself]

You may find Small Bore heating Systems and Copper Tubes in Domestic Heating Systems helpful.

 

[Avatar]

A word of advice - you can come unstuck doing a monoblock tap for the first time.

My first bathroom instal was an absolute nightmare, almost everything leaked.

The one thing that has saved my bacon over three years which I have run my onw business, and now I am quite the expert in almost all areas of plumbing - I dont bite off more than I can chew!

if I get offered work that I know I have little experience of, I have either turned the job down, given it to someone else or brought someone else on the job who was capable - I even did this a month ago, after three years of solid experince!!!

Take my advice - you are no way compentent to install a complete central heating system! You will cause a load of damage which I am sure your landlord will hold you responsible . . .

I have only just branched into installing full systems myself, whoch I do alongside a time served plumber with 30 years in the trade (he does the gas, and even the boiler - which I wouldn't touch myself for another year or so)

Seriously you are mad! Dont believe the course provider who tell you you can do full instlls after the course, as they are salesmen and are simply lieing to you!

I would think again - start off hanging a rad or 2 seriously, or you will come unstuck!!!

 

[dave knight]

thanks for all the responses folks. much appreciated.

heres a little more info.

my landlord is actual a fairly good friend, and, being fully aware of my current level of qualification, asked me to fit the central heating. its on no time frame, and he has said he is happy for me to use it as experience. i am under no illusions as to the fact that i will need assistance, and at no point did i claim that i was a super plumber who was going to do it all on my tod, regardless. no one, at training centre or otherwise, has patronized me by telling me what i may or may not be able to do. i have assesed the house, investigated what may be needed (which this question is a part of) and decided, on my own, that it is a job i am more than confident that i can complete. perhaps i am not mad, just a better plumber at this stage than you were. no training in the world is better than real world experience Avatar, but i wasnt on here looking for permission.

the training centre is BTSC in chessington. and i am fully aware it has recieved a lot of bad press from others. in my experience, the training has been fantastic. the management however, not so. regardless, i am where i am, and its onwards and upwards as far as im concerned.

the water heate is in the location where the new combi will go, so in regards to gas pipe sizing, i'm hoping the current pipe work will be ok. however, as it wont be me installing the boiler, i shall leave that decision to an expert. its a very compact cottage, with kitchen and bathroom (also the location of said water heater) located at rear on ground floor, lounge at front, with just the 2 bedrooms upstairs. i have pulled up floorboards, and spoke to my neighbour (whos house is same as mine, all be it extended and central heated already), and found that the intermediate floor joists run front to back, with only one solid wall in the way.

so, my plan was/is, to have boiler connected to the original cold supply and hot water outlet, then run up into the roof space, and in 22mm speedfit, run the central heating from the back, to the front, branching off for the rads. both front room and front bedroom, and kitchen and rear bedroom rads, are going to be in line, so in theory the instal will be fairly straightforward. then of course, back to copper (15mm) for the runs to the rads.

i was under the impression, wrongly it seems, that a combi did all the timing as well, didnt realise i would need stats etc. so thanks for that 😱)

thanks again for the advice. and Avatar, your post was really helpfull, dont get me wrong. it was just the last few lines.

 

[Spudhater]

Dont forget to get Public Liability in case you flood the place or even blow it up , you will soon find that your "friend" will soon not be your "friend"..

You could be paying for it for a very long time...do you really want to take that risk!!

Scary ..........................................

 

[johnmcginty]

Dont forget to get Public Liability in case you flood the place or even blow it up , you will soon find that your "friend" will soon not be your "friend"..

You could be paying for it for a very long time...do you really want to take that risk!!

Scary ..........................................

How very true , oh how I will never help my "friend" move a washing machine on a knackered ten year old lino ever again! Good luck with the install though bud. Maybe get him to write a disclaimer🙄

 

[Chrisgy]

i was under the impression, wrongly it seems, that a combi did all the timing as well, didnt realise i would need stats etc. so thanks for that 😱)

You can get the combi with a built in timer, some come as standard, some are an extra. If it's got a timer on boiler its not essential you have a room stat, but either way there should be a rad with no TRV on it.

 

[dave knight]

cheers guys.

 

[Spudhater]

"BOILER INTERLOCK" Read up Chris...😕


11 Boiler interlock is not a physical device but an arrangement of the system controls (room thermostats, programmable room thermostats, cylinder thermostats, programmers and time switches) so as to ensure that the boiler does not fire when there is no demand for heat. In a system with a combi boiler it can be achieved by fitting a room thermostat.
In a system with a regular boiler it can be achieved by correct wiring interconnection of the room thermostat, cylinder thermostat, and motorised valve(s). It may also be achieved by more advanced controls, such as a boiler energy manager. TRVs alone are not sufficient for boiler interlock.

 

[Chrisgy]

I said if it's got a timer it's ok

 

[Avatar]

I have learnt my own way in the trade by 'doing it the hard way' like yourself - it sounds like you have given it some thought and have a decent head on your shoulders (essential in plumbing!)

I even trained at the same centre as you it seems. I have a few pointers which might help you on your way:

1) break the install into sections. Instal runs of pipework, renew rads, trv ect room by room and really take your time.

2) the advice about liabilty insurance is sound, might be quite cheap (unlike mine as I have 10mill commecial cover!)

3) Get help from as many sources as possible (this forum for example) - see if there is an independant merchant near you that may be well informed. If you offer the boiler instal to someone, try and see if they are helpful and might give out advice (you will learn loads on this one mate!)

3) You may need help re; rad sizes - like I said butter up another gas safe plumber, offer them the job plus any other gas related that you may get. It is amazing how helpful even a time served plumber is when you are holding their meal ticket. My partner for this kind of work is 30 years in, and has saved my bacon on many occassions. He thinks I am great cause I chuck him loads od work!

Ask if you get stuck!

 

[Spudhater]

Timer and roomstat .... Best practice ( and no dont mean you, best practice as in CHESS) CHeSS central heating system specifications - Overview

 

[Chrisgy]

Yeah best practice probably doesn't matter here...

 

[Toddyplumb]

Chris , you are digging a hole ! It needs a stat

 

[Mbear]

One thing I forgot to mention b4 is u need to think about where the boiler is gona be sited, can the wall take the weight, can the flue be installed relatively easy and In Accordance With manufacturer instructions(what material and how thick is the wall). You can fit the boiler and flue and u can run the gas pipe but u cannot connect the new gas pipe to the meter/current pipework(basically u can fit the gas pipe at the boiler and run it back to the meter, cap the pipe and leave It like that until the guy who is doing the commission).

U can't commission ur work, but u can do alot of gruntwork in readiness for the man with the acs to come along and connect the gas/tightness tests, take burner pressures/gas rates, flue gas readings and basically properly commsion the installation.

 

[Spudhater]

This is what apprentices should be doing for at least 3 years, taking up floorboards/ notching joist is a skill that they dont teach on "fast track".😀

 

[oldplumber]

great reading what people think and advice, especially those that say you dont need room stats etc. guys back to the class for your and learn some regs. As for diy installs, if you own the property why not, if its some one elses, proceed with caution. Best rule is to get someone to mentor you, do the planning and be in the background, its not a black art in the end is it, or we wouldnt be doing it proffessionally. my only worry is dont touch the gas side and let a rgi do the boiler install and commisioning then your in the right. Thinking back to my first install, it was on my own place 25 years back, my cousin did the planning, ordered the kit, lent me a torch and showed me how to solder joints and off I went, and back he came to commission the boiler and all went ok. So lets all be chilled here and say off you go, be sensible, get insurance and start learning your trade if thats what you want to do, be tidy and take your time and above all read the dammed instructions.

 

[easyt]

I'm not saying that it is right or wrong. I have never had a roomstat as such. Always had thermostatic rad valves except for bathrooms. Been happy with that set up. Seems to give me a good level of control and predictable room temps. I could never understand the need for someone to have a roomstat in their hall for example.

 

[oldplumber]

I'm not saying that it is right or wrong. I have never had a roomstat as such. Always had thermostatic rad valves except for bathrooms. Been happy with that set up. Seems to give me a good level of control and predictable room temps. I could never understand the need for someone to have a roomstat in their hall for example.

As a retired highways engineer, why are you proffering advice to people on a subject that isnt your speciality? My issue with your advice is that it is wrong and doesnt meet modern regulatory standards, so you are introducing your opinion and not factual information which then causes confusion. If theres a question on sub base depths etc then go ahead and answer but on issues of central heating wouldnt you be better off observing rather than advising?

 

[Avatar]

A room stat (as a boiler interlock) is required by both building regs, and quite often the manufacturers instructions.

Its point is to switch the boiler off in the event that all the trvs are closed, but the boiler is still going full tilt (for econonmys sake as much as anything!)

A lot of people skip installing them however!

 

[Toddyplumb]

If you have no room stat your boiler is on for the entire timed on period, your flame might go out but your pump is still running , your radiators cool the water (relatively quickly) the flame comes back on and the "cycle" continues . Wastes a lot of gas
With stat you are looking at the room temp , which will keep its temp longer than the circulating water as you have heated the mass of the building and it is acting like a storage heater , stat turns pump and everything off, saves gas

Avatar, if all trv's are shut room temp will not be going up and room stat will not shut down boiler .
Boiler overheat however will in your example