What was found
FLT 3155 - BOS-SAV - CLIMBING THRU 10,000 FT, "ICE DET 2 FAIL" APPEARED ONE EICAS. RAN QRH PROCEDURES AND CONTINUED CLIMB. CLIMBING THRU FL180 AT APPROX 0950L IN ICING CONDITIONS WITH THE ANTI-ICING 'ON', CABIN PRESS WAS LOST. DECLARED EMERG. AT 10,000 FT, L/G RETRACTED AND EICAS THEN DISPLAYED "LG AIR/GND FAIL." RAN QRH AND APPLIED APPROPRIATE PROCEDURES AFTER EXITING ICING CONDITIONS. DUE TO AMOUNT OF FUEL O/B AND AN O/W LANDING ISSUE, DETERMINED THERE WOULD BE NO DANGER OF DELAYING LANDING ABOUT 25 MINS FOR FUEL TO BURN OFF. LOWERED L/G AND SELECTED FLAPS 22 TO AID IN BURN OFF. LANDED ON RUNWAY 04R AT BOS WITH NO FURTHER DIFFICULTIES AND TAXIED TO GATE. FOUND PNEUMATIC OUTFLOW VLV DIAPHRAGM DRY ROTTE