In my 1955 house the fireplace in the lounge has been blocked up and a vent
placed at ground level.
In the adjoining room there is a vent some 3' up the wall which I expected
to be there to facilitate a circulation of air in the flue. However, when I
take the grill off it reveals an open 3" asbestos pipe which appears to
enter the flue and turn in a downwards direction.
There is a similar vent to the chimney at first floor level but I have not
yet removed the grill to examine behind it. In both cases there is a narrow
shelf above the grill.
The removed grill has an integral box section at the rear which has been cut
into the bricks of the wall.
Any knowledgeable thought on the purpose of the vents would be appreciated.