Supply air pressure must be greater than the pressure of the exhaust air. Too little pressure of air entering the recuperator in relation to the outgoing lead intake air from outside through the holes, leakage, Flues,chimenys etc .
Ugavi hewa shinikizo lazima kuwa kubwa kuliko ya shinikizo la kutolea nje hewa . Kidogo sana shinikizo la hewa ya kuingia katika uhusiano recuperator ya hewa zinazotoka kuongoza ulaji kutoka nje kwa njia ya mashimo, kuvuja, Flues, nk .