15mm gas pipe to combi?

[John D v2.0]

Our boiler vaillant ecotec 24 pro was installed in 2012 by the previous owners. No documentation whatsoever. The guy who owned the place before made a big thing about how they had a completely new gas pipe run for the boiler.
Recently I took up the laminate floor to find the gas pipe directly below the floorboards which didn't seem ideal but probably OK.
Looking at the gas pipe near the boiler its a 2m run of 15mm with one elbow, and the rest of the run is around 9m of 22mm with 7 elbows including a tee t the hob.
Now I tried to check the pipe sizing using a PDF calculator and I got around 1.3mb.
Basically my question is should I be concerned?

 

[Dan Robinson]

Probably not, but ask the engineer to check on the next service.

 

[Hot&Cold]

Put your hammer away.The gas rate can checked to ensure your boiler has the correct heat input ,have a look in the boiler installation/servicing book look for the section 'checking gas flow rate (or similar) 'follow that procedure to put your boiler into service mode or similar mode for checking gas rates.

find an App (google or apple) or do the calculation
https://play.google.com/store/apps/details?id=com.mrcombi.ratedemo

A guide on doing gas rate calhttps://www.youtube.com/watch?v=P5OaNL6mMQ0

 

[John D v2.0]

Put your hammer away.The gas rate can checked to ensure your boiler has the correct heat input ,have a look in the boiler installation/servicing book look for the section 'checking gas flow rate (or similar) 'follow that procedure to put your boiler into service mode or similar mode for checking gas rates.

find an App (google or apple) or do the calculation
https://play.google.com/store/apps/details?id=com.mrcombi.ratedemo

A guide on doing gas rate calhttps://www.youtube.com/watch?v=P5OaNL6mMQ0

Thanks, hammer is away now! but the whole floor is up since november, we are insulating the floor, hence the concern.

I've run the boiler on P01 test program for 1 minute and got 1.4 turns of the dial which is 2.38m3/h. The rating plate of the boiler has so many different power ratings I'm not sure which to use.
P01 is "maximum heat input"
the specifications say on p63 of https://www.vaillant.co.uk/downloads/ecotec-pro-instn-maint-261423.pdf (sorry about the size):

The table in the section on checking flow rate talks about "heat output" not input on p35

So 2.38 is just about in the range for 24, which is in the model number of the boiler..! Any thoughts?

Edit: corrected typo

 

[John D v2.0]

Boiler rating plate:

Gas pipe of concern down from the meter and going across at floorboard level:


PS we've had absolutely no trouble whatsoever with the boiler (touch wood) it's got excellent hot water and it heats the rads really quickly, no strange noises or errors etc.

 

[John D v2.0]

I've looked a bit more in the manual and it says it should work down to 13mb, so that sounds like there shouldn't be an issue. I also realised there is an extra 90 elbow I didn't spot in the 15mm pipe right at the boiler!
Thanks for the advice!

 

[Dan Robinson]

I've looked a bit more in the manual and it says it should work down to 13mb, so that sounds like there shouldn't be an issue. I also realised there is an extra 90 elbow I didn't spot in the 15mm pipe right at the boiler!
Thanks for the advice!

The 13 mbar is measured at P1. It is to take into account pressure loss across the internal gas train.

 

[John D v2.0]

Thanks Dan, well it sounds like the real problem will be when the boiler's changed and can't be commissioned. We won't want to rip any floor up then, so given the floor's partly up now it sounds like better to get it done now! And we can get the ridiculous pipework sorted by the meter in one go.
Do you know, are gas engineers allowed to reposition meters slightly if they're repiping the outlet anyway?

 

[Dan Robinson]

It depends on their competence, the meter and a few other things.

 

[fezster]

It used to be the case (approximately 5 years ago when I was looking at this) that a gas safe engineer with MET1 credentials can move the meter as long as he leaves the primary ECV in place. He can then add a secondary control valve. I'm sure one of the gas safe guys here will confirm, though. Only your local transco can move the incoming gas main and primary ECV.

EDIT - to correct myself, I think some said the meter could only be moved as far as the flexible pipe allowed. I ended up using my local transco, as I wanted it positioned some distance away, so was never able to confirm.

 

[John D v2.0]

Thanks guys, well within flexi range is ok. Extending to where I'd really want it would be a no go as the electric consumer unit is between where it is and where it should be. And shortening the service pipe would work but probably cost a fortune as it's some ancient iron screwed pipe that's rusty.
Ideally I'd want it outside, but I'm guessing they'd dig up the drive to lay a new service for many £££

 

[gasbanni]

It's nothing if a job to replace the 15mm that's under the floor with 22mm, it's not even a full length if copper.

Simply put in the 22mm, come up vertically with a 22mm elbow a small length of 22mm then a 15mm reducer. The 15mm can always be replaced at a later date as it will be seen that it's 22mm coming up from under the floor .........nothing of a job.

 

[fezster]

And shortening the service pipe would work but probably cost a fortune as it's some ancient iron screwed pipe that's rusty.

Mine was an old looking rusty iron/steel pipe, but inside it was a much newer yellow mdpe pipe. Could be cheaper than you think even if they had to feed a new mdpe pipe through your existing - but chances are, that's already been done.

Having said that, any work by your local transco is going to be expensive. I moved my meter by about 3m, but the total job to allow for cutting back from the property and then diverting to the new location, totalled about 8m (including a couple of 90 degree bends). Cost was around £2k five years ago.

 

[John D v2.0]

It's nothing if a job to replace the 15mm that's under the floor with 22mm, it's not even a full length if copper.

Simply put in the 22mm, come up vertically with a 22mm elbow a small length of 22mm then a 15mm reducer. The 15mm can always be replaced at a later date as it will be seen that it's 22mm coming up from under the floor .........nothing of a job.

Would be, unfortunately that specific part of the floor with the elbow isn't up and has a 110mm branch pipe and kitchen ventilation fan/intake fan in front of it. I'll have to remove them before hand. Got to be done though!

 

[John D v2.0]

Cost was around £2k five years ago

Well given Thames water charged 299 pounds to glance at a drawing, that sounds positively reasonable!
I would probably pay 10% of that but 2k is silly!