I ask this because it happened to me.....is there something close to the Tstat that generates heat during the day, causing the Tstat to read as satisfied even though the rooms temperature feels lower during the day than at night?

Our Tstat was on a wall in the living room, and the TV was close to the wall. We have the TV on frequently during the day. House always felt one temp during the day, and then warmer at night. Finally we realized that the TV was putting out heat and that was raising the temperature close enough to the Tstat to have it read as satisfied at the set temp, even though the actual room temp was lower. So the boiler was not very active during the day. Then at night with the TV off, it was very active.

Something like that may be happening to you.

Additionally, your older home probably has more infiltration at the basement (I am guessing it is stone and does not have insulation and a vapor barrier...) and has more cold air seeping in there. This may be mixing with the air in your first floor where the Tstat is located, and would be a colder air mix at night when outdoor temps are lower. Combine that with the hot air in your home rising during the night, and that may explain some of the temperature stratification you experience.

Have you actually checked the temperature at the radiators themselves in the day and middle night to see if they are vary by different amounts day/night?

Do you have a one-temp type of Tstat, or a programmable one? Either way, try dialing it back a bit when you go to bed and see what happens. (but you will be cold at 6am!)

I don't think that is the issue. I mean literally the house is perfectly fine until like 2 in the morning. Then every radiator is releasing steam it is getting so hot. This morning the 2nd floor was 80 degrees according to a thermometer in my house.

Thermostat was set at 67.

There must be something wrong with the thermostat if it is set to 67 and parts of the house are at 80 degrees!

What kind of thermostat do you have and how old is it?

It is a Honeywell RT8500 that I installed myself in the last year. It replaced a very old mechanical thermostat from the 60's.

Bump

Are you sure the thermostat was set up correctly for a steam system when you installed it? Did you check to see if you have programmed the thermostat correctly? It sounds like it has been programmed to go to 80 degrees at 2am. Check to see that each day has been correctly programmed.

Have you called your heating contractor? Perhaps the pressuretrol is not functioning correctly.

I rechecked the thermostat and it was fine. It was programmed to go to 71 at 10pm, but nothing odd at around 2.