Boiler swap?

Our old non-condensing boiler had 22mm for most of the distance, then

Perhaps he's trying to factor the cooker out of the equation because the pressure at the boiler would fall below minimum if the cooker was in use. Or perhaps he wants a less obstructed run to keep the pressure higher.

(I am not a gas engineer; these are just my observations and what the guy said to me)

Take a look at the FAQs below. Why are you wanting to change the boiler?

Well thanks for that, but no answer I could find in the FAQ's.

Why, well because our boiler is getting on a bit in years and is perhaps due for replacement with something more efficient.

Firstly, can't help unless you say how long the existing pipe run is from the meter to the boiler.

Secondly get some more quotes, not just to benchmark prices, but also proposed method.

Jim A

Jim Alexander was thinking very hard :

The 22mm pipe is around 8m long, feeding a never used gas pipe, the boiler and a gas hob (electric oven).

OK, look at the recent "combi size advice" thread for some background. Did a confidence check using you data assuming a largish combi and a full cooker and the results are bordeline for 22mm pipe, hence I predict your installer is trying to slip in a combi and has probably reasonably advised larger diameter pipework. But if by regular you mean non-combi, there should not be a problem with using your existing pipework.

Perhaps the main lesson is that as the customer you need to specify at least the type of boiler you want. As far as make and model is concerned, fraid there is no consensus.

Jim A

So all the stuff about there only being 1mbar drop in gas pressure in the installation pipes didn't have any bearing on your situation?

The regs are much more tightly enforced that they used to be. Modern boilers can be less tolerant of poor gas supply pressure.

Jim Alexander brought next idea :

Regular as in a direct replacement boiler except it is of the modern and more efficient condensing design. Retain everything else, as in - header tank, hot water tank, radiators pipework etc. just a new boiler plus new controls.

If the hob is just too much for the gas pipe. it is best to run a 15mm for the hob back to the meter - cheaper.

So that narrows your choice to a "heating only" boiler or possibly a system boiler if you can find one that will run vented. Having said that switching to a sealed system would not represent significant change - you would just no longer need the header tank - and would open up a much wide range of choice.

Since you are talking about going the combi route then gas pipe size will be less of an issue since the maximum power demand on the boiler (and hence gas requirement) will be lower.

I know it was early in the morning (or very late at night :-) ) but should there have been a 'NOT' before 'talking'?

Owain

Indeed there should...

Without seeing the entire layout, existing fittings, materials and methods of construction. The 'best' way to improve the layout of the gas installation is no more than educated guesswork.

Anyone who knows anything about gas supplies has the boiler on its own independent gas supply.

So two meters for two combis?

Please eff off as you are an idiot.

At least.

Best of all is to put the second combi on a LPG gas tank so you have total redundancy when North Sea gas runs out.

I believe Drivel is making his own methane digester powered by hot air, to produce something worthwile out of all the s*it he talks.

Back to normal then. Are you back on the booze too?

Oh no. A separate pipeline run all the way back to Kazakhstan