Anybody out there with knowledge of Heat Reclaim /Air Handling Units please? Scenario is that one of these had been positioned on a roof adjacent to a toilet extract plant and is effectively drawing foul air back in to the building. I am looking for specs on where these units should be positioned in relation to other plant, and whether the contractor was wrong to position it where it is.

As a basic point, yes - foul air should not be drawn back into the building. Check the Welfare Regs - comment is made in that document. Also check out the section in life called 'common sense'

Cant you point downwind of the prevailing wind? Extra filters possibly, increase the distance from the contaminant source or http://www.tesco.com/gro...ct/Details/?id=276631844

I ahave some initial thoughs on what we might consider - first point of call being to the installers, but wanted to do a bit of research first. We have thjought abouit raising the units and/ or retro fitting ducting / trunking to both units - although theire is obviously an issue then with the motor power required.