I just moved into a new house, and I don't think my boiler is working properly. I have a v8 oil boiler, when I turn off the thermostat it still keeps running. It turns on randomly for 5-10 minutes and then shut off and does this about 20 times a day. I changed the thermostat thinking that would be the problem but it wasn't.

Is it possible that your boiler also provides domestic hot water? If so, the room thermostat would not need to be calling for heat, a demand for domestic hot water would fire up the boiler.

I just moved into a new house, and I don't think my boiler is working properly. I have a v8 oil boiler, when I turn off the thermostat it still keeps running. It turns on randomly for 5-10 minutes and then shut off and does this about 20 times a day. I changed the thermostat thinking that would be the problem but it wasn't.
Thanks for answering back, but my boiler does not heat up my water this is separate. Could it be the emergency on and off switch ? I'm thinking it could be this because the previous owner did not control the boiler with the thermostat but with this switch.

Well it appears you have already figured out the problem. You need to have someone check the control circuit. Perhaps the previous owner has over ridden the thermostat circuit. At any rate you need to have it taken care of to keep from paying for heat you don't need, and to keep your comfort level where you want it.

Is there a way to check if the control circuit is working properly ?

Many boilers are set to maintain a temperature weather calling for heat or not. What this does is allow the boiler to instant hot water to heat your house without a recovery time. This is a very expensive (utility) way to run a system. Call a local Boiler professional and have them check to see if they can retro fit some energy saving controls. Your check book will thank you.