Need advice on combi boiler replacement

AAM21

Dear all,

I need some advice on the combi boiler replacement. I live in 3-bedroom midterrace house with one bathroom. I already have got several quotations and I have a choice between the following boilers:

Worcester Greenstar 24i/28i junior
Vaillant ecotec pro 24/28
Vaillant ecotec plus 824
Potterton Heatmax He Combi 24kW/28kW
Viessmann vitodens 100/200

One of the installers says that he can provide 5 year boiler warranty as he is accredited boiler installer for Worcester/Vaillant/Viessmann. Can I trust this? How it is possible to check that? Additionaly, he is persuading to go for Worcester because of their brilliant customer service in comparison with Vaillant/Viessmann.
Another installer is not accredited for boiler companies and his quotations are cheaper by 100-200 quid. However, he provides only 2 year warranty for boilers and 3 year warranty for the job.
Thinking of the insurance the installer with 5-year warranty is more cost effective because boiler insurance costs around 150 quid a year that means 3 year of insurance would cost 450-500 quid.
What would you reckon on these options?

The second question is about pipework. I have 22mm pipe coming out my gasmeter but for the last 2-3 meters it changes to 15 mm pipe. Most of installers say that according to the last regulations there should be 22mm all way through the pipe. However, one of the installers had actually measured the gas flow and said that this last segment does not decrease the flow significantly, so I can avoid opening the floor boards on my first floor. Until present my old boiler Worcester 24i PSF worked pretty well and there were no any problems with insufficient gas flow. My question is: do I really need to change all the pipework for 22mm or it is possible to leave 15mm segment? Will it affect the work of the new boiler?

Thank you in advance!
Alex

lrr_2

I live in a 3 bedroom semi and have the worcester 28i and never had any problems with it. As for the pipework I would rather just get it done as it might be grey area if anything does go wrong. Better safe than sorry.

b830ag2

Hi,

I am currently looking into getting a new boiler too, and I am considering a Combi. Currently I have got a Regular heat-only boiler, so I have been quite thorough (I hope) in researching the requirements for fitting a combi boiler.

With a 3-bed semi- I guess you will prob be ok with the boiler's you quoted. The main requirement for sizing a Combi is for the hot water flow rate. If you can get one big enough to give decent hot water flow rate, then in general, it will also easy be enough to cope with the central heating demand.

The thing is, that I have found, if you just go for a massive boiler to make sure you get hot water flow rate, then you also have to ensure your water and gas supplies are up to the job. Mains water has to have good flow rate, 20 l/min for instance, and good pressure 3-4 bar I would think to enable to boiler to operate to max properly and achieve the specified flow rates without being starved. Also, the gas suplpy has to me man enough too. I rough guide would be to look at the gas inlet connection size on the boiler, i.e. is it 15mm or 22mm. if it's 15mm, which i think those you quoted probably are...then your existing 15mm pipe should be good enough, as long as you've not got huge gas suckers elswhere in the system.

i plan to pressure test my mains this weekend and ask the plumber (when he comes in to quote) about the gas flow rate, as i will almost defintely need a constant 22mm gas pipe to supply a combi (i'm lokoing at a Baxi 40HE or a Worcester 37CDi i think).

juliusceasor

AAM21 wrote: »

Dear all,


One of the installers says that he can provide 5 year boiler warranty as he is accredited boiler installer for Viessmann. Can I trust this?

yes if he is accredited check with Viessmann first.

AAM21 wrote: »

Additionaly, he is persuading to go for Worcester because of their brilliant customer service in comparison with Vaillant/Viessmann.

Vaillant you can spend hours on the phone Viessmann and Worcester are much better in that order.

AAM21 wrote: »

Another installer is not accredited for boiler companies and his quotations are cheaper by 100-200 quid. However, he provides only 2 year warranty for boilers and 3 year warranty for the job.

And how is that backed up?

AAM21 wrote: »

Thinking of the insurance the installer with 5-year warranty is more cost effective because boiler insurance costs around 150 quid a year that means 3 year of insurance would cost 450-500 quid.
What would you reckon on these options?

no brainer go with the five year.

AAM21 wrote: »

The second question is about pipework. I have 22mm pipe coming out my gasmeter but for the last 2-3 meters it changes to 15 mm pipe. Most of installers say that according to the last regulations there should be 22mm all way through the pipe. However, one of the installers had actually measured the gas flow and said that this last segment does not decrease the flow significantly, so I can avoid opening the floor boards on my first floor. Until present my old boiler Worcester 24i PSF worked pretty well and there were no any problems with insufficient gas flow. My question is: do I really need to change all the pipework for 22mm or it is possible to leave 15mm segment? Will it affect the work of the new boiler?

Yes under maximum demand rate which is usually full flow hot water, most gas checks are done with the boiler on not under maximum load. What you are checking for s the Pressure drop between the meter and the appliance. 1mB is the permitted drop. The 15mm segment will have an effect as will and elbows or bends and length of pipe run. It is recommended that 22mm pipe minimum is run up to the appliance if the boiler is going to be in excess of 26kW then 28mm pipework should be looked at.


O I am biased and will declare my interest I am in the trade and my preference is Viessmann but the Vaillant and Worcester product are equally great, in my opinion that order. If you go with the Viessmann unit my advice to you would be the 200 with weather compensated controls; you'll pay that little bit more but it's a bullet proof unit plus with Viessmann you get 10 years warranty on the Heat exchanger.

AAM21 wrote: »

Thank you in advance!
Alex

You're very welcome.

mikey72

If the boiler insurance includes annual servicing, and covers the rest of the system, you need to compare that to the greater installation cost, and the cost of the annual service you will need to pay for to maintain the warranty.
Probably works out the same overall.
Do you have a gas cooker and/or gas fire in your house as well as the boiler?

AAM21

Thank you everybody for your thoughts! I think I would go for Vailant EcoPro 28, change the pipework for 22 mm and 5 year warranty guy.

Marsdendean

We only install Worcester boilers, and can offer 5 years parts and labour with Worcester (were accredited installers)

We tend not to Install Vaillant because of the extra costs over Worcesters. Also, we tend to install CDI'S because they have the digital display (helpful for faults) and include the integral filling loops along with a couple of extra things - The juniors are slightly smaller thou

AAM21

The update> I have checked the specification for Vaillant Ecotec pro 28 and it says that the gas inlet required is of 15 mm. It is a litlle bit of confusion: regulations say about 22mm and the producer says that 15 mm will suffice.

mikey72

AAM21 wrote: »

The update> I have checked the specification for Vaillant Ecotec pro 28 and it says that the gas inlet required is of 15 mm. It is a litlle bit of confusion: regulations say about 22mm and the producer says that 15 mm will suffice.

Depends on the supply, but usually it's 22mm except for the last couple of feet, (or inches) then it's 15mm.

roddydogs

Daft thing is, you cant have a 15mm feed, it must be 22mm, even if the Boiler Takes 15mm so why do they still do boilers with a 15mm input?

mikey72

roddydogs wrote: »

Daft thing is, you cant have a 15mm feed, it must be 22mm, even if the Boiler Takes 15mm so why do they still do boilers with a 15mm input?

It's marginally easier to run a 15mm pipe under the boiler.