Weil-Mclain Boiler 10 years old no problems til now. Burner comes on Pressure goes to about 32psi, very shortly. Have never had to bleed for air as it seemed to do very well with the Spirovent. Checked the Expansion tank tapped the valve and air came out, the top of the expansion tank gets slightly warm as though no hot water had entered the tank. The only thing that was done is the service people replaced the oil filter and replaced the burner nozzle just within the last 30 days. Any ideas why the 30psi is being tripped? Thanks for any help.