The pressure guage on the Potterton Boiler(4 years old) is marked 1 to 5, the red area is between 4 and 5. The red arrow is on one and the black arrow on 1.5 does this mean the pressure is too low, do I add water to increase the pressure please? Could this be why the radiators on not hot enough or is their another reason?

Rita, January 2009