Does the Ensbury LT power flame boiler require shunt pumps and is there a minimum flow rate required? Hamworthy Heating June 11, 2018 10:08 Updated Follow The Ensbury boilers do not require back end protection pumps. There is no minimum flow rate required with these boilers. Related articles What are the NOx emissions of the Wessex ModuMax mk3 boiler? On the Wessex ModuMax mk3 254kW boiler header kit - do the skids bolt together and use 1 shunt pump or does each boiler set have its own pump? Comments 0 comments Please sign in to leave a comment.