G4 meter max kwts that can be run off it?

[billski]

Got to do a gas safety certificate on a big house!
Property has 3 boilers, range cooker and inset gas fire. Total of 70kwts.
Aprox 45 mtrs of 28 mm copper pipe.
Gas volume is 0.0347 so I'm just below the limit for domestic, but does any one know what the max kwts I can run off the G4 meter? And if I've got that all wrong pls let me know! Cheers.

 

[EvilDrPorkChop]

64kw.

 

[billski]

So it's running too many kwts, but I'm sure I read somewhere there is some sort of allowance calculation as it's highly unlikely every appliance would ever be running at max rate. Trouble is I can't find that calculation anywhere now!

 

[EvilDrPorkChop]

At 6kws over it's not much, i've heard G4 meters can nearly do 7m3/h. The easiest way would be to turn all the appliances on and Gas Rate it and see if the meter is reading the correct amount.

Can't say i've heard of the 'allowance' calculation, however as you say it's unlikely all the appliances will be at full load all at once.

Is 70kws the gross inputs of all the appliances?

 

[billski]

I think it's more likely 82 kwts now. Couldn't find the mi's for the duel fuel range cooker so estimated that was about 15kwts, just found it on line and it's 24!

 

[EvilDrPorkChop]

Should be a U16 meter then. Bit of a funny one though isn't it, i've got a customer in a very similar situation but more over than that. However they quoted him about £10k to upgrade the meter and main which he ain't going to do!

 

[billski]

Wow! Is it not possible to just switch the meter over then? Does the supplier charge for that?

 

[EvilDrPorkChop]

No as the incoming gas main wasn't big enough to handle a U16 meter. If they install a U16 meter the main has to support it, so it was a question of upgrading the lot. If you're incoming is only 25mm over a bit of a distance it ain't going to handle it. If you can get away with upgrade the meter they'll sure charge you just for that too! Any excuse.

If had issues on G4 meters recently where they've redone the gas mains up the old steel ones and we're only getting 17/18mb at the meter and that's only over 5/6 meters from the road.

 

[ShaunCorbs]

5k to switch to a u16

why 3 boilers?

also there diversion eg all wont be run at once

 

[billski]

Yeah I've just found the diversity factor calculation in my book. 3 boilers as 1 for 2 unvented hot water cylinders, 1 for ufh and rads plus 1 for a swimming pool. Don't know who installed it!

 

[ShaunCorbs]

i would say its on the limit


how you doing the gas safety on the pool boiler as thats a sep ticket

 

[billski]

Works out at 7.31m3 per hour with the diversity factors.

 

[EvilDrPorkChop]

Is it possible to range rate any of the boilers down a bit?

 

[billski]

Is it possible to range rate any of the boilers down a bit?

That's an idea!
They're all Potterton Pro max. 2 system boilers and one combi. I'll look it to it unless any one knows off the top of their head if they can be range rated?

 

[ShaunCorbs]

dont think so

 

[firemant]

Surely, done properly, the rating has to be done at MAXIMUM appliance consumption, and allow the diversity factor. From a practical point of view it would work, but does not make it comply. Not that it would necessarily be an issue, unless you are signing something off.

 

[billski]

Surely, done properly, the rating has to be done at MAXIMUM appliance consumption, and allow the diversity factor. From a practical point of view it would work, but does not make it comply. Not that it would necessarily be an issue, unless you are signing something off.

They're about to rent the property so needs a gas safety cert.

 

[EvilDrPorkChop]

Surely, done properly, the rating has to be done at MAXIMUM appliance consumption, and allow the diversity factor. From a practical point of view it would work, but does not make it comply. Not that it would necessarily be an issue, unless you are signing something off.

Surely that would depend on the appliance, if it’s an older appliance that could be range rated anywhere from 11 to 18kw you would go off the figure it is set as for it’s intended purpose.

 

[ShaunCorbs]

Surely, done properly, the rating has to be done at MAXIMUM appliance consumption, and allow the diversity factor. From a practical point of view it would work, but does not make it comply. Not that it would necessarily be an issue, unless you are signing something off.

Try telling that to the networks / meter people anywhere upto 7m3 on a 6m3 meter they will say it’s fine with diversity

 

[Harvest Fields]

Got to do a gas safety certificate on a big house!
Property has 3 boilers, range cooker and inset gas fire. Total of 70kwts.
Aprox 45 mtrs of 28 mm copper pipe.
Gas volume is 0.0347 so I'm just below the limit for domestic, but does any one know what the max kwts I can run off the G4 meter? And if I've got that all wrong pls let me know! Cheers.

How is 70kw below the limit?

 

[billski]

How is 70kw below the limit?

Volume of gas is under 0.035 so it's not commercial.

 

[firemant]

Surely that would depend on the appliance, if it’s an older appliance that could be range rated anywhere from 11 to 18kw you would go off the figure it is set as for it’s intended purpose.

Try telling that to the networks / meter people anywhere upto 7m3 on a 6m3 meter they will say it’s fine with diversity

They're about to rent the property so needs a gas safety cert.

Evil: Regardless of the age, and I get what you mean, in that you SET the level, as opposed to a mdern bouler that modulates, all calcs should be done at the maximum possible level. If, on the other hand, you are trying to get an existing situation working then I agree, you would set the boiler to a level that works.

Shaun: The networks seem to get away with making up their own rules, and a lot of their guys do not understand boilers. They do their tests with the HW on, and refuse to acknowledge that the "test" is with the boiler at FULL rate. When I did a stint with NG 3/4 years ago, there was an old BG (from the mid 70's) guy who blamed, specifically, Worcester boilers for the pressure problems because they "sucked" the gas out if the system. I tried to explain how modern boilers worked, but he just was either not capable, or refused, to understand.
But, Shaun, 7m3 propbably would be okay if that was before the diversity factor is applied (if that iswhat you mean?)

Bill: Re the cert, I had missed that. If everything works okay, and eg the hob is not droppong when the boiler is not on full, then one would note the discrepency, and issue the LL. If there was an issue, then you would apply the procedure.

 

[Harvest Fields]

Volume of gas is under 0.035 so it's not commercial.

Surely that has nothing to do with it? We can work on up to 70 kw’s. Once you get to 70 it is out of our scope?

 

[billski]

Surely that has nothing to do with it? We can work on up to 70 kw’s. Once you get to 70 it is out of our scope?

I think you're getting a bit confused. I think it's max on one appliance up to 70kwts for domestic, but if the total is say on 3 separate appliances adds up to more than 70kwts it's okay.
And Firemant, yes you're right. Gas safe have said I should advise the client of the meter being too small ( 7.3m3 was after the diversity factor! ) and tell them to get the supplier in to take a look and see what they think, but if I see the flame is affected on the hob with all the appliances running I should AR it. I can also still carry out a landlord gas safety check and issue a certificate even though the gas volume will now be commercial if a bigger meter is fitted. That's because you don't have to do a tightness test, which seems a bit odd to me.

 

[ShaunCorbs]

I think you're getting a bit confused. I think it's max on one appliance up to 70kwts for domestic, but if the total is say on 3 separate appliances adds up to more than 70kwts it's okay.
And Firemant, yes you're right. Gas safe have said I should advise the client of the meter being too small ( 7.3m3 was after the diversity factor! ) and tell them to get the supplier in to take a look and see what they think, but if I see the flame is affected on the hob with all the appliances running I should AR it. I can also still carry out a landlord gas safety check and issue a certificate even though the gas volume will now be commercial if a bigger meter is fitted. That's because you don't have to do a tightness test, which seems a bit odd to me.

Wrong if your doing a llgsc all appliances together upto 70kw

 

[EvilDrPorkChop]

Have to say I thought it was up to 70kw appliances not the across whole install.

On the point of a U16 meter and gas safe certificate not needing a tightness test then surely this would then become a commercial safety check in which you’d need the commercial qualification.

 

[Harvest Fields]

I think you're getting a bit confused. I think it's max on one appliance up to 70kwts for domestic, but if the total is say on 3 separate appliances adds up to more than 70kwts it's okay.
And Firemant, yes you're right. Gas safe have said I should advise the client of the meter being too small ( 7.3m3 was after the diversity factor! ) and tell them to get the supplier in to take a look and see what they think, but if I see the flame is affected on the hob with all the appliances running I should AR it. I can also still carry out a landlord gas safety check and issue a certificate even though the gas volume will now be commercial if a bigger meter is fitted. That's because you don't have to do a tightness test, which seems a bit odd to me.

I disagree with the above about the 70kw’s

 

[Harvest Fields]

Have to say I thought it was up to 70kw appliances not the across whole install.

On the point of a U16 meter and gas safe certificate not needing a tightness test then surely this would then become a commercial safety check in which you’d need the commercial qualification.

The only way that would work is if there was more than 1 meter

 

[billski]

Wrong if your doing a llgsc all appliances together upto 70kw

I disagree with the above about the 70kw’s

Call Gas safe then. Any single appliance up to 70kwt for domestic and the total number of kwts from all the appliances is irrelevant. You can do as many kwts on a llgsc check as the meter can take.

 

[Harvest Fields]

Call Gas safe then. Any single appliance up to 70kwt for domestic and the total number of kwts from all the appliances is irrelevant. You can do as many kwts on a llgsc check as the meter can take.

Haven’t got time to debate this mate. On my way out for the weekend. Maybe one of the other mods can take a look please.

 

[firemant]

Call Gas safe then. Any single appliance up to 70kwt for domestic and the total number of kwts from all the appliances is irrelevant. You can do as many kwts on a llgsc check as the meter can take.

I am not commercial, and have never had the issue, but that sounds right to me. I thought commercial was an APPLIANCE at 70Kw, OR based on pipe volume. (>o.035?). Existence of either one will kick in commercial ticket requirement. I would not stake my house on this, though.

 

[billski]

I've called gas safe and they have told me it's fine. No limit on kwts with appliances added together and up 70kwts for a single appliance for domestic.

 

[Last Plumber]

The 70Kw comes from standards and regs which are generally used in domestic situations and will cover the installation of hot water boilers and all that goes with them (such as their associated flues and ventilation) up to but not exceeding a maximum of 70Kw net.
That is per appliance. It does not mean that you have to divide the 70Kw between all the appliances you install in one premises.
Other standards exist for larger appliances.

 

[Last Plumber]

If you had a U16 installed you would (as you know) be working on a commercial sized installation.

 

[billski]

If you had a U16 installed you would (as you know) be working on a commercial sized installation.

Only if the m3 volume was over .0035 including the pipe work, which in this case it is, but it won't always be just because it has a U16 metete. Yes I know it's now commercial but I'm still allowed to do a llgc on the property as a gas tightness test is required. I will get a friend in who has a commercial ticket though to tightness test it for my own piece of mind.