Gas rating an appliance

[jordyrusty]

Hi apologies of this has been asked before but when you gas rate an appliance and trying to compare to the technical data, do you go off the Domestic hot water input as that’s a higher figure than the central heating max? Thanks

 

[Deleted member 120897]

What mode did you gas rate in?

 

[jordyrusty]

Was an ideal boiler so set the programmer calling for heat then max rate the boiler and ran hot tap to stop boiler overheating

 

[Deleted member 120897]

I was always told all hot taps for maximum gas rate, or follow the mi’s for gas rating (will be in the servicing section).

 

[Last Plumber]

You need to run at as high as you can get it by whatever means. e.g. on a Vaillant you would set it to P1 to run at Max rate, either on heating or DHW.
Using DHW will allow a continuous run so long as the flow rate allows the boiler to lose enough heat.

 

[jordyrusty]

Thanks for the reply! Yeah I went out and did a vaillant the other day, stuck it on p1 and then 100 for max. But when I was trying to do the gas rate at the meter the boiler stopped firing up halfway through doing it?

 

[Deleted member 120897]

If it’s up to 91 degrees, or there about, it will stop, and start again once temp dropped. Next time try P1, running the dhw tap and turning the room stat to max, it might work, it might not. If you’ve a partially blocked heat exchanger then it’ll get to temperature quicker and take longer to cool down.