In another topic,
I know the theory behind this - the path through the HW cylinder acts as the bypass. But is it always true? No only when the MPV is in the "HW only" position or the mid-position. When it is in the "CH only" position there is still a need for a bypass to allow for the increased head as TRVs close down. This would suggest that, if you have an MPV and TRVs, the bypass should be fitted after the MPV in the CH feed.
bengasman said:If you have a 3-port valve, close the bypass as you won’t need one.
I know the theory behind this - the path through the HW cylinder acts as the bypass. But is it always true? No only when the MPV is in the "HW only" position or the mid-position. When it is in the "CH only" position there is still a need for a bypass to allow for the increased head as TRVs close down. This would suggest that, if you have an MPV and TRVs, the bypass should be fitted after the MPV in the CH feed.