include for heat recovery in apache

[jaycb]

HI,

i have a model set up with AUX vent and space heating using apache.
i have the aux vent supplied to the room at 18 degrees.
i have the load but the system i have has heat recovery at around 70% and the boilers load doesn't include for this. Can anyone explain how i can do this.
i have apache hvac but no used before. Wondering if this is the only to model it, if so basic explanation would be useful on how i do this.

many thanks in advance James