noticed today a loud click from my boiler (Apollo)
read it might be short of water? is this automatically fed?
all I know is above the boiler - a few inches - is a pipe going into the
ceiling, one of 3, but this one looks as though you could attach a hose to
it - is this to drain it or fill it etc.
any info appreciated
im a electrical/mechanical tech by trade, so just need some info