Potterton Neataheat 10-16?

The fan went wrong on my boiler yesterday, a replacement was fitted today and worked for approx 1 hour, it didn't appear to be the smoothest sounding fan but didn't run untrue. The motor got very hot when I removed it it was very hot. After cooling I wired it back in and it run ok but obviously didn't want to leave it in. Can someone confirm that it is just a faulty new fan or is there anything else i should check. The polarity was correct.