width of gas intake pipes

[Dan Robinson]

don't know if anyone ever measure the gas pressure with the boiler running. Having said that, the pipes were new 14 years ago, this was a new conversation when I bought it from a housing association, so I would guess they stuck to the regulations but spent not a penny more than they needed to.

don't know to be honest where the pipe reduces to 15 mm.

You would hope. But my experience of boiler installation in London conversions is not a good one in this respect.

But if the boiler is working it is a 30 second test.

Surprised no one has done it though.

 

[Agile]

I always expect to properly size gas pipes but customers prefer the cowboy with the gift of the gab!

 

[Mignonnette]

Sorry to get back to where I was, if the current boiler (combi) worked ok with the pipes as they are, and the new boiler has 15mm intake, being Vaillant, am I right to assume the current piping ought to be OK?

 

[mickyg]

Sorry to get back to where I was, if the current boiler (combi) worked ok with the pipes as they are, and the new boiler has 15mm intake, being Vaillant, am I right to assume the current piping ought to be OK?

no you assume wrong. Working ok and working to current regulations are not the same thing. Your current boiler could be working with a 5mb drop across the carcass. It would work fine as would the new one, but if other factors come into play later on(drop in supply pressure, added appliances etc) then you could have a dangerous situation.

 

[Gigas]

Assumption is the mother of all f ups....
It sounds like you need an upgrade on the pipework.
Also the next engineer who comes could find a 1.1mb or higher drop on pipework and shut it off. That could be middle of next winter. Couple of days without boiler..... Brrrrrrrr.

 

[ianmcd]

Assumption is the mother of all f ups....
It sounds like you need an upgrade on the pipework.
Also the next engineer who comes could find a 1.1mb or higher drop on pipework and shut it off. That could be middle of next winter. Couple of days without boiler..... Brrrrrrrr.

Why would an engineer finding a 1.1mb drop shut it off Gigas ????

 

[RickMoore]

Assumption is the mother of all f ups....
It sounds like you need an upgrade on the pipework.
Also the next engineer who comes could find a 1.1mb or higher drop on pipework and shut it off. That could be middle of next winter. Couple of days without boiler..... Brrrrrrrr.

Why would an engineer finding a 1.1mb drop shut it off Gigas ????

Because your only allowed 1mb drop across the pipework.

I get a little annoyed at manufacturers insisting a minimum sized pipework, the calculations are easy enough after all, I feel it kind of encourages people to either a) do DIY gas, or b) not bother with correct sizing.

To the OP, truth is no one can say that the pipe needs changing without doing the calculations first. If the boiler manufacturer states min 22mm then that superseeds the regs so even 1m of 15mm would be unacceptable even though the calculations would say otherwise, but the calculation still needs to be done as you may need some 28mm for example.

 

[Agile]

This OP seems very reluctant to accept that the 15 mm is too small. May need some pipe at 28 mm !

A simple measurement on the existing boiler will give good clues!

Tony

 

[DP]

If the boiler manufacturer states min 22mm then that superseeds the regs so even 1m of 15mm would be unacceptable even though the calculations would say otherwise

Rick, can see what you are getting at, but in this case there will be a length of 15 dia pipe since the inlet to the boiler is that bore. There is no getting away from the fact that each installation has to have correctly sized pipes for the system to function correctly

 

[picasso]

Would anyone really shut a boiler down on a drop of 1.1mb ? as long as the manufacturers minimum working pressure is meet cant see any reason to shut it off.

 

[Biggles..]

Exactly. Scaremongering isn't going to help.

If the drop exceeds that of the current standards and the manufacturers minimum is met with no adverse affects then its only Not to current standards.

 

[pampers]

the answers been said a few times but untill some one says what you want to hear i dont think this will stop.

if you upgrade you gas pipe ,the boiler will work to its full capacity , it will meet current regulations ,be fitted (gas wise any ways ) to manufacturers instructions.

If you dont upgrade or at least have it tested and sized it may well not work to its full capacity ,wont meet current regulations, will probably at best be classed as NCS if you have a landlords cert or inspection of some sort,wont be to manufacturers specifications so could void any warranty's, but it will work to some degree.

 

[Mignonnette]

I am not reluctant to accept that if the pipe isn't adequate it needs replacing. My problem is I have had five quotes on this job. None of the people who quoted have measured the boiler's working pressure (the last one to be fair couldn't, the boiler is not working now). My problem is that I have had at least one complete cowboy quote, British Gas who were clearly ripping me off, two of the others said no need to replace the pipe and the final one, who on current reckoning is going to get the job, bumped the price up £250 while watching my expression when he did it.

So that is my problem. Where do I find a gas engineer who is both honest and competent? I appreciate all the advice everyone's given me, and the frustration of those who feel that customers go for the lowest price no matter what but tbh I have lived in this flat 13 years now and am really tired of being given the run around by people who are interested simply in making as much money as they can out of me.

 

[Dan Robinson]

Not sure what more we can add for then. On the info you have given us you pipe has to be upgraded.

One approach I take with customers is to tell them it might need it. Price the two separately.

Turn the new boiler on and measure.

It is either right or it isn't.

 

[ianmcd]

Assumption is the mother of all f ups....
It sounds like you need an upgrade on the pipework.
Also the next engineer who comes could find a 1.1mb or higher drop on pipework and shut it off. That could be middle of next winter. Couple of days without boiler..... Brrrrrrrr.

Why would an engineer finding a 1.1mb drop shut it off Gigas ????

Because your only allowed 1mb drop across the pipework.

I get a little annoyed at manufacturers insisting a minimum sized pipework, the calculations are easy enough after all, I feel it kind of encourages people to either a) do DIY gas, or b) not bother with correct sizing.

To the OP, truth is no one can say that the pipe needs changing without doing the calculations first. If the boiler manufacturer states min 22mm then that superseeds the regs so even 1m of 15mm would be unacceptable even though the calculations would say otherwise, but the calculation still needs to be done as you may need some 28mm for example.

Sorry Rick on one line you say that "boiler manufacturer states min 22 mm then that superseeds the regs" but you are arguing about an excess of a 1 mb drop across the carcass is what the the regs state where some manufacturers clearly state in the MIs that they will accept 16mb at the appliance ? I agree that it is a nightmare to get it right but also agree that our only get out clause is to install to Manufacturers instructions and if these contravene GSIUR then make sure it is noted in writing somewhere,