Upon arrival unit was on but not running. Temp in the house was 73 and the thermostat was set to 71. Turned temp up to 76 and unit started up with no issue. Cycled unit on and off multiple times with no issues. Checked all radiators and all of them were getting hot. Compared the thermostat temp to a temp probe and found the thermostat is reading 3 degrees warmer than the indoor temp is. Most thermostats have a 3* temperature variance. The thermostat may be starting to go bad. Adjusted the hi and low limits on the boiler aquastat so the burner will run for longer periods of time. Unit is working properly.