Yep, just remove the 240vac connections from your timer contacts and replace it with the two contacts from the heater. The timer would then switch the contact closed to enable the heater.
Howdy @MSchutzer, could you elaborate on this a bit? I realized that if I use my timer to control the coil on a contactor to completely power down the heat pump, then I will lose my temperature setting.. Trying to understand how I can use my AC powered timer to instead control the P_S switch inside the heat pump..
If you want to control the power through the pressures switch, just disconnect one side of the pressure switch. Run that to any timer that has normally open contacts, you likely are not switching more than 120V, probably 24V, and very small amperage. Take another wire from the other side of the timer contact and install it to the pressure switch. Set your timer for the time you want the contacts to be closed and the heat pump will run if all else is ready.