C
Christian
Hello, i have a baxi instant 105e and the pressure relief valve is letting water out of the external over flow pipe when ever the water pressure goes over 3bar.. i have had an external expansion tank fitted about a year ago. i have just fitted a new relief valve and within 10 minutes the pressure had risen to 3.5 and there is now a very fast drip out of over flow pipe. what is causing the pressure to rise in the boiler to cause the pressure relief vave to blow ?? pease help !!