it has to be replaced as it is open flued i think, i cannot get the pic any bigger and eyes aint great lol
Not 100% EPH ... Just checked out Parts Arena and it looks like an SD27 or SD33 .. No Mi's on there but you could try emailing Saunier Duval. I didn't know you could still get open flued water heaters? I fitted a fan flue Main a cupl of months back!
Reply to the thread, titled "Identify this w/heater?" which is posted in UK Plumbers Forums on Electricians Forums.