DIY Central Heating Installation Advice

[madmax]

Iv just Joined this forum so hello everybody

Ok, we have just moved into a 3 bed semi in newtown wales, it basically had no mod cons apart from what it had from new 1950`s.

so im having the gas main installed early next month, so im now at the point of getting the central heating installed.

after getting a few quotes, ( approx 5 - 6k) and reading through some posts on here, im confident enough that i could easily install rads/pipework myself ( industrial mechanical/electrical fitter of 22 years).
so, my first question on here is, i know i need a gas safe guy to connect/commission, but can i hang the boiler (vaillant) and fit the flue water pipes etc?

if i can, then i have tons of things to ask lol.....

 

[Blackcatgas]

Iv just Joined this forum so hello everybody

Ok, we have just moved into a 3 bed semi in newtown wales, it basically had no mod cons apart from what it had from new 1950`s.

so im having the gas main installed early next month, so im now at the point of getting the central heating installed.

after getting a few quotes, ( approx 5 - 6k) and reading through some posts on here, im confident enough that i could easily install rads/pipework myself ( industrial mechanical/electrical fitter of 22 years).
so, my first question on here is, i know i need a gas safe guy to connect/commission, but can i hang the boiler (vaillant) and fit the flue water pipes etc?

if i can, then i have tons of things to ask lol.....

Do it your self nooooooo, get your flame proof suit on your going to get shot down on this forum, Rads and pipe work is easy enough, hanging the boiler is easy enough make sure you get the position of the flue correct, 300mm away from any openings etc, there is a page in the mi book nthat comes with the boiler. However I think that you will struggle to get a Gs reg engineer to come and connect up the gas and commision the boiler, I get asked all the time to do the above, I tell them politely No.
do your rads etc, leave 2 22mm pipe stubs down to the boiler and get a GS reg engineer to fit the boiler etc.

 

[madmax]

lol, see, thats why i joined this forum.

so then, if i buy all the stuff, install the rads/pipework etc and leave the stubs of 22mm then i should be able to get a gas safe guy to do the rest?

ok

question 2

iv got 15Kw of rads here to fit, and im looking at vaillant combi boilers, can i check, would the vaillant 831 be adequate? looking at the specs the 15KW i have is near the middle of its modulating range

can i take my flame proof suitoff now lol

 

[Blackcatgas]

lol, see, thats why i joined this forum.

so then, if i buy all the stuff, install the rads/pipework etc and leave the stubs of 22mm then i should be able to get a gas safe guy to do the rest?

ok

question 2

iv got 15Kw of rads here to fit, and im looking at vaillant combi boilers, can i check, would the vaillant 831 be adequate? looking at the specs the 15KW i have is near the middle of its modulating range

can i take my flame proof suitoff now lol

The Vaillant 831 is my favourite flavour of combi boiler, Ive got one in my own house.
Most combis even little ones will **** the central heating side, its the bigger power for the hot water demand that you need, the 831 will give you more than enough for your 3 bed semi.
I dont reccomend that you fit the boiler yourself, however if you do I think that you will find it hard to get a GS engineer to finish it off for you, I personaly wouldnt touch anybody elses gas work that has been left for me to "finish off". what are your other questions?.

 

[madmax]

thanks for the answer, i wondered how far i could go without out upsetting the gas safe guy. so ill leave the boiler fitting to the expert ( can you reccomend any in the mid wales area?).

my other questions are

1. im intending to run 22mm pipe for the 1st 2 - 3 meters up under the floor, then because im going to have to run the length of the house through every floor joist, im thinking of using plastic 22mm then 15mm to rads, dropping down to lower floor rads as i go. are there any problems you can see with me doing this?

2. the position i want the boiler fitted has a vent above it, there are 2 in the kitchen, can 1 of these be used to put the flu pipe through? ( i know im now leaving it to a gas safe guy to fit, but just so i know approx where to run the pipes if this position is not suitable).

3. do i need an automatic air bleed on the flow return pipes upstairs at the highest points? reading speed fits instructions the reccomend this on drop feeds .


4 do i sound a complete novice here lol?. i just want to make sure i do this job once and not have to spend hours adding to the system.

 

[Blackcatgas]

thanks for the answer, i wondered how far i could go without out upsetting the gas safe guy. so ill leave the boiler fitting to the expert ( can you reccomend any in the mid wales area?).

my other questions are

1. im intending to run 22mm pipe for the 1st 2 - 3 meters up under the floor, then because im going to have to run the length of the house through every floor joist, im thinking of using plastic 22mm then 15mm to rads, dropping down to lower floor rads as i go. are there any problems you can see with me doing this?

2. the position i want the boiler fitted has a vent above it, there are 2 in the kitchen, can 1 of these be used to put the flu pipe through? ( i know im now leaving it to a gas safe guy to fit, but just so i know approx where to run the pipes if this position is not suitable).

3. do i need an automatic air bleed on the flow return pipes upstairs at the highest points? reading speed fits instructions the reccomend this on drop feeds .


4 do i sound a complete novice here lol?. i just want to make sure i do this job once and not have to spend hours adding to the system.

The 1st meter of 22mm pipe from your boiler needs to be copper, heating design is a very complex thing and far beyond what Ive got time or space to right here... but do the following and youl be okay, use speed fit plastic under the floor by all means, I like it, some on here dont like plastic, its personal preferencwe, rule of thumb is dont run more than 3 rads off 15mm pipe work so if youve got 8 rads try to get the first 5 off 22mm circs, (you run up to each rad in 15mm btw), you dont need a aav bleed valve on the highest point of the system, the highset point of the system will be the top of the highest radiator upstairs which you will bleed via the air pip. the tails on the rads should be in 15mm copper, connect 15mm plastic to theses tails under the floor, make sure you use inserts in the plastic, mark the pipe before pushing toghether to maker sure its gonerinto the fitting all the way.Pressure test the system after youve finished by connecting it up to the mains cold. any surface mounted pipe work to the rads etc will have tobe in 15mm copper,plastic looks gash and turns into wibbly wobbly snakes going up the wall with any heated water going through.

 

[madmax]

i was going to run the 22mm up to the other end of the house, then t off in 15 to each rad individually, i looked at copper, but plastic is much easier to use ( cheaper too) iv used it in industry in the past and its never let me down.

good tip for pressure testing, i didnt think of doing it that way thanks.

1 other question, do i need to clip the 15 mm runs under the floor boards running parallel to the joists? ( save me ripping up boards every 1/2 meter)

 

[Blackcatgas]

i was going to run the 22mm up to the other end of the house, then t off in 15 to each rad individually, i looked at copper, but plastic is much easier to use ( cheaper too) iv used it in industry in the past and its never let me down.

good tip for pressure testing, i didnt think of doing it that way thanks.

1 other question, do i need to clip the 15 mm runs under the floor boards running parallel to the joists? ( save me ripping up boards every 1/2 meter)

You should clip the pipe really to stop it from touching any cables, getting snagged on any sharp bits of wood etc.

 

[madmax]

lol, well,thanks for the good advice, ill post again if i get into any trouble.

 

[doitmyself]

One thing you obviously have not taken into consideration is: what happens if something goes wrong?

If you buy the boiler and it then turns out to be faulty the GSR who installs the boiler can legitimately say, "I didn't supply the boiler so it's not my problem guv. You'll have to get in touch with the manufacturer and ask them to come and sort it out."

If the GSR installer provides and installs the boiler he is responsible for any faults and for getting them repaired while under warranty.

In any case a GSR will be able to purchase the boiler for less than you.

 

[madmax]

hi there, yes i have taken that into consideration, and iv found that some installers offer you either cheaper boilers, or boilers they are registered to fit ie worcester.

i did originally want a worcester and rang them for assistance, the only info i got from them was speak to one of our registered installers.
what made me plumb for vaillant is when i rang them, they were brilliant, they emailed me tons of helpfull stuff, they also said that as long as its fitted and commissioned in line with their manual by a GS engineer then warranty is not affected.

is £800 expensive for a brand new Vaillant ecoplus 831?

 

[oldplumber]

why dont you ask in an independant plumber for a quote, explain what you want to do and ask if he will design your system, give you a spec to work to. You will have to pay for his time, but at least you should get an idea of what is needed and how to do it. Then at least the heating side should meet building regs specs for hot/cold supplies etc. Your plumber should then be happy to hang the boiler and commission it for you and be happier in his own mind when its signed off. I have done this in the past and its the only way I will sign off a boiler as I dont want to be blamed for a poorly functioning heating system. At the same time get a quote for parts from him, if you get on well I bet you cant get parts cheaper even with his commision added on.

Not being biased but speedfit is the only plastic system Ive had leak on me, twice, hep2o is my favorite even if u have to pay more for it, but it seems to stay on once pushed together and the pipes are more supple and easy to un bend off a coil.

 

[madmax]

Thanks for the advice, i may try that, i did ask one of the companies that gave me a quote if i could do the plumbing myself, but he wasnt happy ( less money for him) the same guy said the newly installed system would need a power flush for an extra £500, not sure that is right, a system flush yes but i thought they only did that on old systems. so that put me off

reading the replies im now a little worried that no ones going to want to know, i have sized all my rads (and bought them) well over the calculators to compensate for a big boiler ( DHW flow rate) and because my wife needs warmer rooms than the calculations say as she had a brain op which left her slightly paralized on one half her body in cold weather she cant even walk with the pain.

hep20, i did look at that initially, wasnt sure because of the cost, and everyone seemed to be raving about how good speed fit is and iv used it before in industrial settings, but if you say you have had problems then ill take another look, thanks for that.

ill get the phone book out tomorrow and see if i can get a guy on board before i do anymore work.

 

[migoplumber]

as said, good to get your local installer on side. if he's any good he will be busy and wont mind coming and doing the last bits for you. a good idea would be to run your plumbing pipework to where it needs to be, and pressurize it first, show your installer your competent !

 

[moony]

plastic cheaper than copper ? where are you getting it from ?

plastic and there fittings are more expensive mate but take less time to install, so as a plumber we offer very little quote difference.

a good tip if using plastic - come down on 8mm in centre of rad chased in come out of a socket back box behind rad and into the chrome pushfit elbows.... this is if you dont mind chiselling walls, the 8mm pipe comes out behind rad and you hardly see it.

 

[stevetheplumber]

plastic cheaper than copper ? where are you getting it from ?

plastic and there fittings are more expensive mate but take less time to install, so as a plumber we offer very little quote difference.

a good tip if using plastic - come down on 8mm in centre of rad chased in come out of a socket back box behind rad and into the chrome pushfit elbows.... this is if you dont mind chiselling walls, the 8mm pipe comes out behind rad and you hardly see it.

ive used a lot of 10 mm for heating and find it works well running down walls isnt realy practical ecept on new builds where theres voids or dry lining but running up behind skirting center of rad and looped up behind rad and down to valves gives a nice clean look with no visible pipework i run the pipe in oval plastic conduit
only problem is with small rads they can move on the brackets as theres no pipework to hold them a blob of silicon on the brackets helps this each rad has its own f and r from manifold so no fittings below floors means it practically leak proof which is good news for laminate floor lovers upstairs manifold usually goes below bath and downstairs below boiler

 

[moony]

sorry steve i meant 10mm late night and all that ha

 

[wistle]

Hi, I am new to the forum and look forward to getting advice from clever people.

I have installed a central heating system with zone valves. The wiring diagram shows the thermostats wired in parallel. So both zones will open when the stats call. I know setting the stats at different temps. would prevent this.
The boiler is a worcester bosch greenstar 28i junior. I have a DT20 twin channel programmer. Can I wire the system so that each zone can be set to come on at different times?
Many thanks
Wistle