November 11, 2025Nov 11 Hello. I’m in the process of replacing an MVHR unit. It's in a 12 year old, two bed, 1 bath flat that had an MVHR installed from new. I'm quite comfortable about the install after a lot of reading, well I hope so anyway. This forum helped a LOT. However, I would appreciate confirmation on two things to make sure I’ve everything right and compliant. 1) Should the ventilation rates be set to the 2021 ADF (not the original 2010 ADF rates)? I assume yes given ADF 2021 section 3.1 “….replacing part of the ventilation system, including extract fans… the work should meet the relevant standards in this approved document.” I only ask as a retrospective uplift in ventilation rates and changes in how the supply is split when changing an MVHR unit seems like it might cause headaches for some depending on how their original system was designed. In my case, it bumps airspeed in the living area supply duct quite a bit due to size and a proportional volume based split. 2) What are my obligations in updating my BCO? My working assumption is no notification is required as it’s Minor Works – section 0.10, but I do need to send them a copy of the commissioning cert – section C4. Is this just a case of emailing the cert to the BCO email address? Thanks
November 11, 2025Nov 11 1. Its maintenance, keep you flow rates as they are. 30 minutes ago, NOC said: changes in how the supply is split You need balanced flow and extract with MVHR, but leave every as set at the terminals and tune fan speed to get back you your original or reduced rates if needed 2. Its maintenance, why do you need to tell anyone anything.
November 11, 2025Nov 11 Author 3 hours ago, JohnMo said: 1. Its maintenance, keep you flow rates as they are. You need balanced flow and extract with MVHR, but leave every as set at the terminals and tune fan speed to get back you your original or reduced rates if needed 2. Its maintenance, why do you need to tell anyone anything. Thanks, really appreciate that. I was afraid I was getting lost inside in the regs.
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