My boiler is a Glow Worm 24 hxi and I am afraid I don't know in great detail what my system is as I have very little knowledge. In the cupboard with the water tank there is a pump and several pipes two of which have two boxes with black switches on marked A and B. One is marked down flow and the other up flow. There is a header tank as well. Other than that I cannot offer any miore useful detail. Sorry!
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