Gas meter size?

[jon26]

Looking to put a separate combi boiler in an annexe extension to the side of my existing property. However I am unsure as to whetehr the existing domestic size U6 capacity gas meter will be adequate to take the full load of both the new combi and my existing boiler system.

The new combi will be around 32kW and the existing one is around 20kW plus a few kW's for cookers, fires, etc.

Am I likely to need my existing meter upgrading to a larger model. I assume the actual pipe size into the property will be ok, its just the meter??

 

[fitz1]

If your combined usage exceeds 6 cubic metres you will require a 16 cubic metre gas meter and probably bigger supply pipework.(about 4 grand)

 

[bengasman]

Theoretically, it would be sufficient, but a lot of service pipes seem too small to really be able to deliver 60 kw without pressure loss.
At the same time, it is unlikely that you have all fires and cooker and boiler working at full capacity at the same time.
Before forking out a lot of money, you should get a RGI to see what your dynamic pressure is at maximum use now.

 

[jon26]

Theoretically, it would be sufficient, but a lot of service pipes seem too small to really be able to deliver 60 kw without pressure loss.
At the same time, it is unlikely that you have all fires and cooker and boiler working at full capacity at the same time.
Before forking out a lot of money, you should get a RGI to see what your dynamic pressure is at maximum use now.

The service pipe seems to be at least 25mm.

 

[charliechaplinspants]

If your combined usage exceeds 6 cubic metres you will require a 16 cubic metre gas meter and probably bigger supply pipework.(about 4 grand)

How can one know how to tell wether the combined usage exceeds 6 cubic metres? Why 6 cubic metres anyway? Can anyone one give advice to the poster in terms that the poster might understand without `showing off ` their knowledge to other fitters/plumbers etc, it is after all a DIY Forum. Thanks .

 

[fazedup71]

after you take into account pressure loss through the pipework with fires, cookers and boilers i bet even 35mm wont be big enough. You need an RGI to look at the system and what you have planned, maybe a seperate service with meter. With every thing you want to run you are getting very close to the limit for a G4/U6

I think the OP's question has already been answered, get an RGI in to look at it. There is so much to take into acoount, how far original applainces are from meter, how far proposed new installation will be. You have 52 KW just for your boilers and it is not a case of a few fires, if you say roughly 4KW for each your up to 60kw then add a cooker!

 

[glasgowgas]

If your combined usage exceeds 6 cubic metres you will require a 16 cubic metre gas meter and probably bigger supply pipework.(about 4 grand)

How can one know how to tell wether the combined usage exceeds 6 cubic metres? Why 6 cubic metres anyway? Can anyone one give advice to the poster in terms that the poster might understand without `showing off ` their knowledge to other fitters/plumbers etc, it is after all a DIY Forum. Thanks .

View media item 11913

 

[fazedup71]

Watch where your pointing that thing!

 

[charliechaplinspants]

after you take into account pressure loss through the pipework with fires, cookers and boilers i bet even 35mm wont be big enough.

35mm for 2 combis ...Don`t think any pipe would be large enough for you mate. ( I`ve just been sick all over me Weetabix).

 

[bengasman]

I would use 35 for that kind of load, at least til the first split.
Better have it and not need it.........
I use 28 for loads over 35kw unless it is a very sort run. Why risk too much pressure loss for 1 or 2 percent of the installation cost?

 

[charliechaplinspants]

I believe the size of pipe being discussed is the one before the meter, i.e. the service pipe?

 

[gas4you]

If your combined usage exceeds 6 cubic metres you will require a 16 cubic metre gas meter and probably bigger supply pipework.(about 4 grand)

How can one know how to tell wether the combined usage exceeds 6 cubic metres? Why 6 cubic metres anyway? Can anyone one give advice to the poster in terms that the poster might understand without `showing off ` their knowledge to other fitters/plumbers etc, it is after all a DIY Forum. Thanks .

G4/6 meter can only supply 6m3/hr. Appliances instructions tell you how much gas /hour they will use on maximum, so just add them all together.

eg a 37Kw combi will use 4m3/hr when on full tilt, so 2 of them could use 8m3/hr etc etc.

 

[fazedup71]

35mm for 2 combis ...Don`t think any pipe would be large enough for you mate. ( I`ve just been sick all over me Weetabix).

Yes 35mm for 2 combis, your also forgetting the cookers and fires that have been mentioned. Discharge rate for 35mm pipe is 32m/h over a 3 meter section so depending on the size of the building and distance from meter to appliances 35mm minimum and am not talking about the service pipe.

This is all very subjective, a site survey is needed

 

[DazzarGaz]

35mm for 2 combis ...Don`t think any pipe would be large enough for you mate. ( I`ve just been sick all over me Weetabix).

Yes 35mm for 2 combis, your also forgetting the cookers and fires that have been mentioned. Discharge rate for 35mm pipe is 32m/h over a 3 meter section so depending on the size of the building and distance from meter to appliances 35mm minimum and am not talking about the service pipe.

This is all very subjective, a site survey is needed

Why are you banging on about 35mm pipe??. Have you ever heard about a pipe sizing calculation?. As a small example 28mm can supply 9.4m3 over 9 meters. Get a proper survey done by a RGI and things might not be as bad as been portrayed here.
The meter size should be regarded as a separate matter as it will be in National Grids/gas suppliers domain and not the RGI. It's probably best speaking to the gas supplier first about getting a bigger meter or even perhaps 2 U6 meters (a bit a lateral thinking!!). A U16 will require a new meter housing.

 

[charliechaplinspants]

G4/6 meter can only supply 6m3/hr. Appliances instructions tell you how much gas /hour they will use on maximum, so just add them all together.

eg a 37Kw combi will use 4m3/hr when on full tilt, so 2 of them could use 8m3/hr etc etc.

Thank you. Most appreciated.