POTTERTON NETAHEAT 16-22 BOILER.
When heating started up this morning there was an almighty bang from the boiler which shook the casing.
A similar problem occurred several weeks ago during the normal heating cycle but nowhere as bad as this
The boiler was serviced about 12 mths ago and apart from this bang works fine
Any ideas please such as a new part needed or worst case a new boiler.
Boiler is 28 years old.