i have a double feed indirect hot water tank in the loft with an access panel which reveals a small capacity water tank, behind this is what appears to be a larger capacity tank which i can't gain access to.
i keep getting an overflow problem from this system and can't figure out why. i have adjusted the ballcock in the small tank and am certain this is not the problem. i feel the larger tank must be overflowing into the smaller tank but don't know how/why?? can anyone help me?