- Joined
- 26 Mar 2005
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- 25
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When it fires on HW , it runs at full rate so the noise you hear is the fan, thats all, if you look in the installation manual you will see that the maximum rate achievable however the boiler is set when on heating is way below this so a 24kw boiler will only give say 18kw on heating.So its the software that controls the heat output.Balancing your system is the best way to get the rads hotter quicker and by range rating the boiler as discussed but an engineer should do this. Hope this helps.