Worcester Greenstar burner gasket failure
All of the Worcester Greenstar range are based on the “premix burner” or “zero governor” design. The design of the premix burner means that the air and gas gets mixed together to a set ratio and is then essentially blown into the burner for combustion.
An important part of this design is the burner gasket or burner door seal if you like. This gasket essentially creates the seal between the burner and the venturi connected to the fan which delivers the air and gas to the burner.
A common problem with the Junior, Si and Ri is the failure of the burner gasket. I find that on these appliances the burner gasket starts to fail on appliances around 5 years old. Some fail sooner and some last a bit longer but generally need replacing after 5 years or so.This is not something that generally stops an appliance from working, but something that can cause damage to an appliance if it fails.
These gaskets tend to fail around the spark electrodes and ionisation probe and usually results in burnt gasses leaking from the heat exchanger and recirculating around the appliance. Apart from being unsafe it usually causes condensation to settle on the inside of the casing which causes corrosion.
If you’re getting your appliance serviced PROPERLY then whoever is doing the job should be inspecting this gasket as failure is very common. A flue gas analysis often doesn’t even pick this up as a problem with emissions.
So the British Gas style of boiler service which doesn’t even require the removal of the front boiler cover is not enough. My advice is to get your boiler comprehensively serviced by someone who knows these boilers and will do a thorough job.
Failure of this gasket is a very common problem on the above mentioned boilers. I probably replace at least half a dozen of these gaskets each week. If your boiler is over 5 years old then it would probably make sense to get this gasket looked at and replaced if necessary by someone competent. I carry this as a stock item for service and repairs.