Gas boiler pressure rises when heat is off?

How did you turned off the heat..it might be you just lower the thermostat all the way down or maybe if your thermostat has an off switch and you just rely on that?...Most thermostat that have off control was only controlling the circulator pump but not controlling the entire boiler. Just go back to your boiler and turn off the switch in there it mostly located outside wall of boiler.

If the temperature is rising in the meter? it means the boiler was still ON and just waiting the thermostat settings to circulate the heat in the entire system. About also the pressure? if it was continue rising means the pressure regulator valve is not working right and need to be change. The pressure regulator valve was located above the boiler where the feed line was connected.

from: http://jra813handyman.webs.com/

If the boiler also supplies the hot water for the house, (showers and faucets) then you only turned off the part that supplies water to your heating fixtures. Otherwise, the boiler would not be hot. If it is heat only, you need to check your thermostat because it's running.

Several factors contribute towards efficiency in a boiler. All the heating system parts need to be in good working condition. Adequate fuel must be constantly available, whether powered by diesel, natural gas or oil. Be sure that the water tank always has adequate water. Temperature and pressure settings must also be correct. You may sometimes experience frequent rising pressure in the system. Below are four possible causes and actions to take.