it sounds like your pump has jammed,or packed up. im not familiar with that worcester so dont know if the pump is within the boiler,or externall ..the two t's are the condense trapfill cycle which worcesters go thru if the power supply is turned off .it lasts approx 20 mins till completion. it will not ramp up fully for heating during this cycle,or at all till the pump is replaced
john
January 2010