Reduction in rent request

[Louise Robaina]

First time posting anything....We have one new tenant.  She is requesting a reduction in rent because we had a heater (vent)  problem that we quickly resolved, but now the unit above hers may have a sink/tub leak that is staining her bedroom ceiling... how do people handle this...?  We got her permission so that next week we can get get the Plummer in the unit and the handyman to repair ceiling or walls.  She finds this stressful and inconvenient.  
looking for some guidance and words of wisdom.  How would an experienced landlord deal with this?  Clearly we are new kids on the block...thanks!