Post
by boilergasman »
Sun Dec 21, 2014 7:31 pm
Hi Guys
Kind of funny all the expert advise here....
First problem :high pressure:most of the combi systems are seald ones. As we are putting the heating on as a normal phenomenon the heated water will increase in pressure. There is a so called expansion vessel in every combi boiler, that compensates that expansion. In case the vessel is old or un serviced, its unable to compensate the heaTEXPANSION, meaning that the pressure in the system will increase over 3 bar, and the so called prv=pressure relief valve will open and release the excess water. When this happens its very common for the prv to catch small rubbish, and after it wont close properly.Solution:simple=service vessel, clean prv.
The high pitched sound is an o ring in the diverter valve that is old and swollen, that causes the terrible noise. If you take the cover off the boiler you can actually identify the direction and the source of the noise. Bottom left part of the boiler. Im just about to sort my one out (have the same problem), in case there is an interest, I can supply the part number of the o ring that needs changing.
good luck