I've just moved into a flat and after hand-washing some dishes this water cylinder (Dimplex SCx175l) began 'draining' very loudly -- I let it go for about 30 minutes before turning off the main water shut off valve.
I am assuming this is a problem with the T&P valve so I'm wondering if it is safe to turn the water back on or if I should call out a professional to solve the issue.
Thanks, Jack