If your going to "gas rate" an appliance, all you need to do is compare the result to the data plate on the appliance as that will give you the heat input.
If your going to "gas rate" an appliance, all you need to do is compare the result to the data plate on the appliance as that will give you the heat input.
Looks like everyone has a different view point
OP says, the back panel is corroded, OP says there is a reduction in flame size when boiler kicks in. The variation between actual reading and data badge would I am sure require further investigation.
Tony I am surprised at your comment about the CP12 being a non invasive test. fact is the actual reading shows a discrepncy which I think you being a clever person not known to making mistakes, will I am SURE you would pop the cover and have a gander inside.
Clearly some answers here would suggest 5 yearly reassement is not a bad thing
There is no need for a CP12 to open the boiler up. All that is necessary is the measure the power input. This can be done from the gas meter!
Tony
2 points here - A RGI must have all the types of appliances he is qualified to work on listed on his card, if they are not there, he can't legally work on them.
Secondly, the domestic WORKING pressure required at the meter test point is 21 mB plus or minus 2 mB. At 18 mb, you're already on a loser. There's a strong possibility the meter governor is at fault and it's not regulating correctly when under load (it's a common problem on older governors) - call National Grid - they will check and replace for free if necessary.
Don't dive in and assume it's the pipework yet.
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local