Installation of a modern electric fire in existing chimney

[OJM]

I am about to install a modern electric fire into a chimney breast that was bricked up. Can anyone tell me if the chimney must be sealed first, and if any other means of ventilation must be added?

Also, is there any regulation regarding minimum/maximum height that the fire must be from the ground

 

[Tom.]

Don't seal the chimney. In fact, if it is sealed, it needs ventilation. You don't want condensation above the fireplace and no breeze to carry it out, because the soot will become acidic, which destroys your mortar.