Yes the Intermatic spring-would timer can perform the function using a DPDT relay
The timer is rated 10 amps @ 240 volt, so the power cannot run directly thru the timer
The timer can activate the relay with no problem ... and then the relay can handle the 20-30 amp AC load
The relay must be DPDT, with 240 volt coil.
Depending on which 30 amp DPDT power relay you chaoose, it will need additional space inside an enclosure for the relay and wiring.


My page on countdown timers ... the Intermatic has a HOLD feature on some models
Countdown-timer-horsepower-ratings.html#FD
FD-series-sell-sheet-with-wiring.pdf

Buy from my affiliate links:
DPDT 30 amp 240 volt power relay
30 amp 240 volt open frame power relay

My affiliate link for FD series timers
120-240 volt Intermatic countdown timers