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Discuss Adding 3 metres of 28mm pipe at the end of a 15 metre 22mm run in the Plumbing Jobs | The Job-board area at Plumbers Forums
I don't know - just trying to summarise the points from the posts. Looks like the later posts say that increasing pipe size anywhere will increase volume, decrease resistance and increase working pressure at the appliance. The issue I am facing is that the pressure drop from gas meter to boiler is too great (around 6mbar) so am trying to determine ways of reducing this pressure drop. I am assuming the gas supply people won't change the governor to increase the gas meter pressure to above 22mbar?
Understood. Just responding to fuzzy's post (look at the text i quoted) about the governor. I think recent changes to the system as part of a recent period of building works have resulted in a both job (we eventually kicked out the builders) so am left o pick up the pieces. I have an RGI coming to look at it but wanted to make sure I did some research first. The reality is that it will be tough to replace anything other than the last 2-3m with 28mm pipe. Perhaps a middle section of about 3m could also be replaced but that is about it without having to dig up walls (which you can understand I would like to avoid). This gives 5-6m of 28mm upgraded from 22mm (but not starting at the meter). But it generally sounds like upgrading sections of pipe to 28mm will help even if in the middle and end of the run (although a number of you have disagreed with that, so how do I convince my RGI if he disagrees as well).
No, been there a couple of years and pressure drop was fine before building work. Recent building work re routed a pipe and I asked them to ensure it was 22mm rather than the original 15mm for part of it. It is possible the measurement at the boiler taken by a boiler engineer a couple of weeks ago was incorrect so it may not be a 6mbar drop, but either way, the drop is high! I just dont understand how they could have introduced a big drop as essentially run is similar to before. Either way the builders are not coming back as I kicked them out for other shoddy work so they won't be solving it. Am hopeful that only sections can be replaced to fix the problem.
It was all part of the building work (so the builders who i kicked out) so they would have contracted someone I think. Don't have the details of the actual person who did it so can't get him back to sort it. The original pipes were put in by another company.
Only problem is that it will either involve digging walls in addition to lifting floor boards (we would need to lift some floor boards in any case for upgrading sections to 28mm) so would rather not look at this option unless absolutely necessary
should be zero then
Not sure I follow. What pressure would they have checked at the boiler then? He seemed to connect a manometer to something in the boiler. Would this be the pressure of the gas just before it hits the burner?Is anyone able to run a quick calculation to see what improvement I get in terms of pressure drop if I swap 5m of 22mm pipe with 5m of 28mm pipe?
