We have done time resolved photoluminescence (TRPL) measurements on low n-doped (up to 3(.)10(15) cm(-3)) 4H-SiC epilayers. Mappings of entire wafers show that the decay time of the photoluminescence on a single wafer can vary by orders of magnitudes and become worse near the edge of the wafer. The observed decay times normally are in the range of 60-150 ns, on single samples decay times up to 535 ns (averaged) could be observed. It is also shown, that on some samples atypical signals with a second peak in the decay curve occur where decay time constants up to more than 1 mus can be found.