What was found
AFTER TAKEOFF THE CREW RECEIVED A PACK 1 OVERHEAT EICAS MESSAGE AND WOULD NOT RESET. SHORTLY AFTER THE ACFT ENTERED ICING CONDITIONS AND BLD 1 AND 2 LOW TEMP MESSAGES APPEARED FOLLOWED BY BLEED 1 AND 2 VALVE CLOSED MESSAGES. THE QRH WAS FOLLOWED AND THE ACFT EXITED THE ICING CONDITIONS. THE FLT RETURNED TO DEPARTURE DUE TO FORECASTED ICING CONDITIONS AT DESTINATION. MX RESET POWER AND THE ENGINES WERE RUN UP AND THE PACK BLEED CHECKED ALONG WITH THE ANTI-ICE SYS AND NO FURTHER DEFECTS WERE NOTED.