no problems last year and serviced as normal. Turned on this year to no heat upstairs. I don`t know alot but have bled rads to no avail, next i have taken off thermostatic controls on each rad to find all pins down as far as they will go, pliered them up but they will not come up independantly. Even wh i did pull them up still thre was no heat to the rads. Pump is vibrating and seems fine set on number three boiler igniting no problems there. Has anyone got any suggestions?