The Test Series A2 research programme was carried out in three parts between March and November 1987 at the Grimethorpe Pressurized Fluidized Bed Combustion Facility. After completion of Test Series A2.1, the equipment for feeding coal-water mixtures was put into operation and Test Series A2.2 (554 hours) was completed using a combination of US supplied Glenn Brooke coal and Plum Run dolomite. This test series was mainly funded by the USDOE. The feedstocks were then changed to UK Kiveton Park coal and Middleton limestone for Test Series A2.3 (301 hours). This test series was funded jointly by EPRI and from residual funds remaining from the IEA Agreement originating from the UK Department of Energy. The filter system supplied by EPRI was under test throughout Test Series A2. Performance data from test series A2, are supplied in relation to the following topics: combustion efficiency and carbon monoxide emissions; sulphur oxide and nitrogen oxide emissions; bed characteristics; heat transfer and system temperatures and pressures; bed material carryover and breakdown; cyclone performance; alkali and halogen emissions; polycyclic aromatic hydrocarbon measurements.