the SE code is not a fault, it just means that a (SE) service engineer needs to call and do an annual service, it usually shows up every two years if it has not been reset at the service visit , you need to get a corgi engineer to service and/or reset the service setting / he can ring worcester for the procedure (neither are shown in any instructions).
the 2 sideway T shapes show when the electric has been turned off and back on again, they usually show for about 15 mins ,the onboard electronics think it is starting from new and are filling the condensate trap, any longer than may need a new pcb check with worcester
phil
February 2008