Replacing some gas piping with 28mm pipe

[dfish]

Hi
I have had five quotes to replace my boiler which is a 32kw Ariston combi. Only two of them want to replace some of the piping - (only 12m to be replaced with 28mm pipe from the meter and leaving the other 10m at 22mm to the boiler). How do I know who is correct?
the boiler was to be replaced with either a 32kw Vaillant or 30kw Worcester.

Thanks D

 

[ShaunCorbs]

as they may have calculated what the boiler requires m3/h and your existing run couldnt supply that

 

[dfish]

Thanks for your help

 

[lame plumber]

i would choose the ones wanting to upgrade the pipework

 

[turnpin]

Whoever you decide to choose make sure they are Gas safe registered......regards Turnpin

 

[dfish]

Thanks that narrows the choice down. One of the guys that said it wasn't necessary thought the 2 that wanted to change the pipe size were just trying to increase the price of the job!!

 

[dfish]

Yes they all are. Thank you.
D

 

[Rickster123]

22m in 22mm? It will need upgrading. Is it a straight direct run or are there bends galore?

 

[dfish]

No bends in the pipe they want to replace but there could be three bends in the remaining pipe.
How do they know that just by replacing some of it will be sufficient.

 

[Masood]

Thanks that narrows the choice down. One of the guys that said it wasn't necessary thought the 2 that wanted to change the pipe size were just trying to increase the price of the job!!

Did this guy base his opinion on pip size calculations carried out, or just threw it out there off the top of his head? 22m pipe run all in 22mm seems too small for a 32KW boiler.

 

[SimonG]

No bends in the pipe they want to replace but there could be three bends in the remaining pipe.
How do they know that just by replacing some of it will be sufficient.

I would say because the blokes are qualified and competent.

 

[dfish]

I don't know. I moved into this property and have had 2 repairs to the boiler in 6 months and its still not right. Thats why I thought I would replace it. If they replace some of he pipe it means I have to re-carpet all the hallway and so I just want to make sure they know what they are talking about. Thanks

 

[dfish]

Ok they are all gas safe registered but giving me different info. I just wanted another unbiased opinion. Thank you.

 

[ShaunCorbs]

Ok they are all gas safe registered but giving me different info. I just wanted another unbiased opinion. Thank you.

as for there calculations if one produces one go with him

 

[dfish]

Cheers thanks

 

[jtsplumbing]

There are ways that we use to calculate gas runs, using given formulas , just one of the things we need to know, that's why we do training courses & take exams that cost us a lot of money to enable us to safely work with gas,

 

[dfish]

Thanks I appreciate that - despite them all being Gas Safe registered they still give conflicting info but this forum has been very helpful. Thanks you

 

[Dotty]

Thanks I appreciate that - despite them all being Gas Safe registered they still give conflicting info but this forum has been very helpful. Thanks you

We've got a few members in Edinburgh. I'm sure they'd be happy to give you additional quotes if you want.

 

[dfish]

Thanks I will probably just go with the quotes I have and accept one of the quotes that includes replacing the pipe. Thank you

 

[ShaunCorbs]

Thanks I will probably just go with the quotes I have and accept one of the quotes that includes replacing the pipe. Thank you

what boiler they installing?

 

[dfish]

A Vaillant 832 Eco Tech plus

 

[lame plumber]

Oh dear

 

[dfish]

Whats the Oh dear refering to. Should I be worried!

 

[Chalked]

Whats the Oh dear refering to. Should I be worried!

Nothing wrong with that boiler. It's just that 10 guys on here will have 10 differing views on boiler make.
Go with the Vaillant

 

[dfish]

Thanks - yes its all these different views that is confusing but it was the pipe recommendations (or not) that was worrying me. Cheers

 

[newcastle phill]

What made you decide on a vaillant ecotec. What was the clincher ??

 

[dfish]

I am a worcester fan but they don't do a 32kw boiler and I believe that both worcester and Vaillant are equally reliable. It wasn't the clincher. I only have 2 quotes who want to replace some of the pipework with 28mm so I will go for one of them. One was Scottish gas and they are the most expensive so I will go for the other one.

 

[dfish]

Have you got a different boiler prreference.

 

[ShaunCorbs]

Have you tried some independent installers ??

 

[dfish]

Yes I had a quote from one and that's likely to be the one I go with.

 

[newcastle phill]

Look at offerings from ideal and baxi.
Both have equally excellent offerings.
The vaillant is just too complex on the user interface needlessly so imho.
The boiler also costs quite a bit more than other competing ones and doesnt offer better reliability or better customer service

 

[Masood]

Another vote for Ideal over Vaillant. But essentially, if you have an installer you trust, go with the brand he or she trusts. If they know it well and are comfortable with it then you'll likely have a smoother install and easier maintenance as they'll know what to look out for when servicing.

 

[dfish]

Thanks I will investigate that.

 

[dfish]

Thank you - its the pipe issue that really concerns me and its knowing who to believe. Its a very costly exercise to rip up my hallway (and if thats not enough to rip up my tiled kitchen floor with under floor heating).

 

[Stigster]

As you have been given conflicting advice on replacing the gas pipe, you could ask the engineer you are happiest with how did they come to the conclusion it needs upgrading. If they did the calculations and that's what the result says they must use then they won't mind showing you.

It's one of those situations where it either does need doing or it doesn't, not much of a grey area between so ask why. Obviously not in a "are you trying to sell me something I don't need" way, it is a perfectly legitimate question when you are paying.

 

[Sparkgap]

Thank you - its the pipe issue that really concerns me and its knowing who to believe. Its a very costly exercise to rip up my hallway (and if thats not enough to rip up my tiled kitchen floor with under floor heating).

*gets out *** packet* 32kW boiler, about 3.5 cu.m/h so about 0.97 l/s for 22mm copper drops about 6.2Pa/m so about 136Pa total for 22m straight run or 1.36 mB which is a tad higher than recommended. 28mm copper drops about 2Pa/m so 44Pa/0.44mB which is okay.
That's not to say the boiler won't work on the smaller pipe. I know plenty installations where the pressure off the meter is actually a bit above the recommended and most boilers won't suddenly curl their toes up if the pressure drops a smidgen below 20mB. Could be your existing boiler is also more tolerant of lower pressures.
If it's that much hassle to do it you could go with the existing pipe and see what happens and look for other routes that avoid digging up the floors if possible.

 

[dfish]

Thank you. Scottish gas seems to think only a partial replacement is necessary and the independant guy doesn't know if that is enough! The latter I don't find satisfactory. Safe Gas registry said I have to ask the right questions, only go with the company that guarantees to complete the task at the price (and then if it doesn't work they have to pay for further work) and finally trust my gut instinct!!! Seriously that's what they said.

 

[dfish]

Cheers Sparkgap. Thanks for such a detailed reply. How sensible you are. I will take this view on board and use this to be more forceful with suppliers. Thanks have a good week.

 

[Scott_D]

Those figures don't allow for any bends, fittings or other gas appliances

 

[dfish]

Ok I understand. There needs to be a degree of flexibility depending on bends and boiler.
Thank you. Such a minefield.

 

[Sparkgap]

Those figures don't allow for any bends, fittings or other gas appliances

Quite agree. I did say straight pipe as I don't know the details of the pipe route. I would be inclined to put in a larger pipe but if it's the hassle the OP says it might be worth waiting to see if the boiler works on the original pipe, bearing in mind the existing one did. Other option would be to suss out another route that doesn't involve digging up floors if possible.

 

[dfish]

Can the pipe route go through bedrooms and outside before reaching the boiler (above ground level).

 

[ShaunCorbs]

Can the pipe route go through bedrooms and outside before reaching the boiler (above ground level).

as long as in trunking i dont see a problem (some nice talon)

http://www.talon.co.uk/images/stories/products/pipe-cover/Talon_Pipe_Cover.pdf

 

[Sparkgap]

Can the pipe route go through bedrooms and outside before reaching the boiler (above ground level).

No probs provided the pipe is in a ventilated space. Looking at some flats at the moment with the gas pipes rising on the outside and internals done in tracpipe through the floor.

 

[dfish]

Thank you

 

[dfish]

Ok thank you

 

[jonnyswamp]

Use a smaller output boiler, may take a bit longer to fill a bath, but may save you shelling out on unnecessary building works
Providing existing gas pipe will be adequate

 

[dfish]

thanks yes I think that is what I am going to attempt to do.

 

[Ric2013]

I would say because the blokes are qualified and competent.

Then why do they have different opinions on this - can it really be a grey area, or are some of them more competent than others? Or have made a mistake?

 

[newcastle phill]

The mistake was probably some being complacent and not bothering to calculate.
I havent read the whole post but i would go with the one who has calculated - as they have taken the time to assess the installation and subsequent gas demands