Copper water cylinder bulge

[kevalicat]

Hello, I have noticed a bulge in the hard foam casing on my hot water cylinder. It seems that the casing has come away like a large blister, I do not think the copper behind has forced it out. Does this sound ok to you guys ?

[gasman]

Occasionaly the cylinder whilst been manufactured may have some grease or some other contaminant left on it, that should have been removed before the insulation is sprayed onto it. When this happens the outer foam casing does not adhere to the cylinder properly and can blister like you describe. Providing there is no evidence of water or a damp patch around the bottom of the cylinder you have nothing to worry about and it does not effect the performance either.