oso indirect cylinder

[peteh20]

has anyone else had problems with the oso cylinders have fitted about 20 over the years. got one where the internal air gap needs to be re-established every 3 to 4 months

 

[oldplumber]

is there as slight leak on the hot outlet allowing air to seep out? only a thought I have heard of this happening but cannt remember the cause at present, best to ring oso tech desk.