Are those faucets the farthest from hot water heater? ... Do you have a hot water tank larger then 25 gals?... if your farthest faucets take up a lot of water in pipes you can lose the heat of the hot water... are all hot water pipes insulated properly?... Is the hot water produced by electric coil? gas heating tank? oil heating the tank?... does you hot water tank have a leak?... is the flame right if gas or oil heated?... did someone lower the aquastat under 120 degrees? should the aquastat be higher if you have a lot of faucets?? are you running a few faucets at the same time using up the hot water fast???