Any plumbers or heating engineers on here?

My Valliant Ecotech combi is dripping from the overflow then when the hot taps running this increases the pressure is right up as well,plumber has put a new blow off valve and various bits £375 now the plumber is not replying to my calls/texts could be hes gone out for day. Need to get this sorted ASAP as we cant av the render wet for when the top coat is applied......Any ideas?

 

Stick a piece of hose pipe on the end it won't cure it but will keep it off the render .

 

yeah done that Mike.