Incidentally, how strict is the regulation of max 1mbar drop from meter to appliance? For example if teh drop was 2.5mbar but the working pressure was within spec for the appliance is this acceptable?
15mm gas pipe for boiler
- Thread starter physco
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There is an internal drop on these boilers, which is why worcester specify down to 16.5 mbar.
If you want a true measure of the drop across the pipework it needs a test point on the gas pipe just before it enters the boiler.
If you want a true measure of the drop across the pipework it needs a test point on the gas pipe just before it enters the boiler.
GasBod wrote
I fitted a Potterton Gold on which the service pipe was pinched and working pressure at the meter was better than 9 you got but ratios were in the gutter. If you got 9mbars at the inlet on the Vaillant, I wonder if you checked the boiler as per the manual, ran other appliances at the same time or you FGA was in caliberation
I fitted a Potterton Gold on which the service pipe was pinched and working pressure at the meter was better than 9 you got but ratios were in the gutter. If you got 9mbars at the inlet on the Vaillant, I wonder if you checked the boiler as per the manual, ran other appliances at the same time or you FGA was in caliberation
Most boilers will work find down to at least 12 mB.
I saw TWO boilers fitted to the end of a long 22 mm pipe. With both on the supply pressure was down to 6.5 mB.
Thats not the point. The regulations demand a MAXIMUM of 1.0 mB pressure loss.
There is another point too. Whilst boilers will work fine with a STABLE supply pressure which is low, with a high resistance pipe the working pressure at the boiler will vary widely, say from 12 mB on full to 20 mB on minimum power. That variation will alter the combustion characterists and cause the CO/CO2 ratio to go out of spec.
Tony
I saw TWO boilers fitted to the end of a long 22 mm pipe. With both on the supply pressure was down to 6.5 mB.
Thats not the point. The regulations demand a MAXIMUM of 1.0 mB pressure loss.
There is another point too. Whilst boilers will work fine with a STABLE supply pressure which is low, with a high resistance pipe the working pressure at the boiler will vary widely, say from 12 mB on full to 20 mB on minimum power. That variation will alter the combustion characterists and cause the CO/CO2 ratio to go out of spec.
Tony
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Worcester do not require 22mm main to an 18Ri ... I have a letter from Martyn Bridges from Worcester that states its not required for any of there boilers and whats required is the correct inlet pressure .. we are a WAI company and have had GSR pull us and they were satisfied with letter
As has been said if youve any doubts ask the installer nicely stating your worries and if still bothered get GSR out for a free health check
It sounds ok to me but I dont know how long the 22mm run is nor what the 15mm run is getting up to but to be honest if I had done the job I would have connected up in 22mm just in case and the cost difference would have been about £15.00
Just so we know did you go for the cheapest quote??
As has been said if youve any doubts ask the installer nicely stating your worries and if still bothered get GSR out for a free health check
It sounds ok to me but I dont know how long the 22mm run is nor what the 15mm run is getting up to but to be honest if I had done the job I would have connected up in 22mm just in case and the cost difference would have been about £15.00
Just so we know did you go for the cheapest quote??
We're a gold WAI too, and Worcester refused to give us such a letter. Because I asked a few years back.
If your installer has not got a letter, the decision is not his to make. Gas Safe register expect gas appliances tobe installed to meet manufacturer instructions. It is not in his power to give the dispensation. Drop him.
If your installer has not got a letter, the decision is not his to make. Gas Safe register expect gas appliances tobe installed to meet manufacturer instructions. It is not in his power to give the dispensation. Drop him.
As far as Worcester have told me - also a Gold WAI - anything above and including an 18ri must have a 22mm supply. Daft as in some cases particularly fitting these in garages the meter is only a couple of meters away. But your warranty may in fact be void as appliance is not fitted to Manufacturers Instructions.
As long as the pressure loss is less than 1.0 mB then I dont see what difference the supply pipe size makes ( in theory ).
With a very short 22 mm supply pipe size I have seen an oscillation occur on a biasi premix.
Tony
With a very short 22 mm supply pipe size I have seen an oscillation occur on a biasi premix.
Tony
Looking at the Ri instructions it says that the gas connection is 22mm, this would mean that a 22mm supply is needed, as you cannot reduce the inlet supply
I dont see how you can logically come to that conclusion!
It is as perverse as those who think because Vaillant have a 15 mm gas inlet the whole gas supply can be in 15 mm.
The gas supply has to have a minimum pressure drop of 1.0 mB. Thats the only criteria.
Many makers say the gas supply has to be 22 mm. Thats only because otherwise cowboy installers would do it all in 15 mm.
Unless it says otherwise in the MI's... daft as it maybe to those who know...
the reason???? As Tony stated.... trying to protect the daft DIY'ers who no no better.
the reason???? As Tony stated.... trying to protect the daft DIY'ers who no no better.
G
gaswizzard
God forbid the working pressure was increased to 30 mb , could get away with a 10mm supply.
God forbid that Libby lou Lou, eagle mind that he/she/he is, should come up with a venturi device that allows this sort of thing
.
G
gaswizzard
Dan did you mean to say He , She or HeShe
Haven't made my mind up yet... Just posting boolacks whilt this abortion of a film runs its course... 1.4 gigs of server space I can't wait to get back
Just posting boolacks whilt this abortion of a film runs its course... 1.4 gigs of server space I can't wait to get back DIYnot Local
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