Microleaks

Microleaks occur in pipework and fittings where due to damage or corrosion air permeates into the system but water does not leak out. In the case shown below a microleak is present below a TRV - the leak has furred itself up with scale and now air gets in but water does not get out. In this case the houseolder had recently had a gravity fed boiler changed to a sealed system boiler, which increased the pressure on the system 3 fold. The symptoms were that the householder had to top up at the filling loop about once a month.