Gas pipe pressure drop calculation

[Rhyss]

Having a nightmare this week. The situation goes as follows:

- Had a new boiler installed 14 months ago
- The installer re-installed the gas line from the meter to the new boilers location.
- All self-certified and gas safety cert received.

• Fast forward to this week

- With kitchen booked in for plastering at the end of the month i reach out to local gas person to have the line extended for the new location of gas hob.
- Upon sending him the details of the existing pipework he's stated that i need a larger line to deal with the new gas hob location, BUT also the existing line(that was put in a year ago) doesn't conform.
- Queue me now researching furiously trying to understand what the regs are and how they're calculated.

From my research and knowledge of the subject (all 24 hours worth), the calculations i can do with one of the online calculators(https://www.gb-gas.co.uk/clc/pipesize/GasPipeCalculator.htm) states that the pressure drop for the existing setup is indeed over 1mbar for the boiler even when ignoring the existing gas hob load.


Would someone who has more than 24 hours experience in this be kind enough to confirm or deny whether i should be going back to my installer stating they commissioned a system which doesn't meet regs?

The existing line is as follows:

Meter (U6) -> 3.9m 28mm -> 90 Elbow -> Reducing Tee* -> 9m 22mm -> 3 90 elbows -> 1 45 form bend -> 32KW Combi Boiler

Reducing Tee* -> 0.2m 22mm -> 90 elbow -> 1m 15mm -> 6 burner gas hob (Assumed around the 12KW-18KW)


Very very much appreciated in advanced

[dingg]

I'd be in contact with the firm that fitted the boiler for a quote for the new work and see what they say.....

Good chance the new man is trying to pull your pants down

[Rhyss]

dingg said:

I'd be in contact with the firm that fitted the boiler for a quote for the new work and see what they say.....

Good chance the new man is trying to pull your pants down

That is my concern!

I've been in contact with the installer for the past 4 weeks however unfortunately he is someone who won't give a date until the week before, and so far all i've had is poor excuses. I will be chasing again tomorrow/Friday, but wanted to try and fully understand.

[Road2Ruin]

Has the drop actually been measured, or are you just using the calculator to guess the drop? I had the same issue (ours was measured and did drop by more than 1mb). The 'fix', though, was not as calculated by that website. The plumber only needed to replace a very short piece of pipe.

[Rhyss]

Road2Ruin said:

Has the drop actually been measured, or are you just using the calculator to guess the drop? I had the same issue (ours was measured and did drop by more than 1mb). The 'fix', though, was not as calculated by that website. The plumber only needed to replace a very short piece of pipe.

It hasn't physically been measured. I've got this from a different gas engineer who i provided the gas line details/measurements to this week and did their own calculations and stated it drops by more than 1mbar. My own calculations using that tool also seem to match.

As i'm absolutely no expert in this field, it means i currently only have this other gas engineers word before going to the elusive installer.

Edited by Rhyss on Wednesday 6th November 14:18