I have just moved into a home with hot water heating. I noticed that even in the summer the boiler still runs Is this a problem?
Yes and no. You have what we call a 'hot boiler'. If it is a big old system, you really want a hot boiler. If you want heat in the house, you do not want to wait for the boiler to heat the water and then wait for it to be delivered to your living spaces. Hot boilers keep the water hot all of the time so that when you need heat it's ready to go.
New boilers hold very little water compared to the old ones. New boilers heat up water very quickly so the boiler doesn't have to run in the summer.