Ozpos

Hi @JohnMo, thank you for your honesty. Could you tell me how long you have been involved with mvhr and at what level ?

No problem but it is a while since I bought some plus delivery is slow. https://www.alibaba.com/product-detail/SCD40-SCD41-gas-sensor-module-Electronic_1600973791358.html?spm=a2700.galleryofferlist.normal_offer.d_title.2a154649rdSLh0

Hi @JohnMo, thank you for your response. I am an electronics engineer and always looking to use my knowledge to save cash. I can get hold of co2 and humidity sensors for a couple of quid. In addition I have built a building control unit using a raspberry pi. Do you know if many mvhr systems can be controlled by an external building management system ?

What about:https://www.duco.eu/uk/products/mechanical-ventilation/ventilation-units/ducobox-energy-comfort#multi-zone-valve They say: Compact external 2-zone control With external 2-zone control, the house is divided into a day and night zone. This zonal control is based on CO2 and humidity. It only provides ventilation where and when needed, in the right amount. Zonal ventilation ensures maximum energy savings and increases acoustic and thermal comfort. So I assume as the day zone time ends the zone valve reduces flow and at the same time backs off the fans to compensate. Can anyone else shine a light on how this actually works ?

Thanks but what about systems that have day time and night time zones ? I do not expect to shut off a zone just reduce the flow to standby/holiday mode. The valves I have seen are proportional. I thought the whole point of zones was one of efficiency ?

Hi @Conor, Thanks for your response. I thought mvhr units run the fans in constant volume configuration such that the air flow is increased if the resistance to flow increases (e.g. due to filter contamination) ? So if I have a zone that is not occupied for certain days in the week then that zone can be restricted with a motorised valve and the air flow reduced to a minimal. At the same time as turning down the zone surely the fans need to be adjusted otherwise they will try harder to supply the constant volume. Could you please explain more ? Best regards, Ozpos

Hi All and thanks for your experienced knowledge. Could anyone please tell me how are the fans adjusted to accommodate the changes in air volume demand when zones are turned on and off ? Best regards, Ozpos