We would like to investigate polycrystalline CaFe2O4 which undergoes two magnetic transitions to a B phase below 190 K and to a A phase below 160 K. Both phases coexist in a narrow temperature range. Preliminary inelastic neutron scattering results show broad magnetic fluctuations in the B phase which could not be reproduced by linear spin wave theory. A comparison with the substituted compound CaFe1.5Cr0.5O4, expected to host exchange disorder and which stabilises only the B phase, shows a similar magnetic spectrum indicating that disorder may dominate in CaFe2O4 in its high temperature phase. We would like to measure CaFe2O4 and CaFe1.5Cr0.5O4 in the B phase using a non-magnetic isostructural compound CaSc2O4 as background, in order to apply the first moment sum rule as an alternative to spin wave calculations in order to extract the exchange constants in the B phase.