My burnham v8 series oil-fired boiler is losing water from somewhere,cant find any leaks,the automatic waterfill is not filling the system,I have to add water every other day,what could be wrong with it,I can't afford another one

My Burnham V8 series won't shut off when it reaches the temperature on the thermostat. We are waisting oil.

SSStevens,
Burnham V7 & V8 series boilers had trouble with the castings. With the boiler hot the water could be evaporating before you get a puddle on the floor. I suggest you remove the sheet metal cover & insulation then inspect the boiler. I may or may not be still under warranty.
Do you have any piping which is hidden in floors or walls?

My Burnham V8 series won't shut off when it reaches the temperture on the thermostat. We are waisting oil.

Prado,
Depending upon the control system on the boiler, it may run until the boiler temperature reaches the set point on the aquastat.