Model 411A has leak beneath metal cover of control head causing loss of pressure. I am unable to see the point of leakage and have replaced the valve assembly. The fault is still the same and there is no obvious fault with the control head but I am now thinking it is to do with the control mechanism in the head and the assosiated seals. There is a white internal nozzle in the centre of the tube when viewed from the triangle face and a filter type push fitting when viewed from the larger round port. I would like the control head and both of these fittings with all the seals to reassemble the control head to the pump. Can you tell me the part numbers and cost. Thanks Charlie