Diagram of Primatic cylinder

[doitall]

If I replace the cylinder with an normal indirect one and add a new F&E tank where do I connect the feed and exp. pipes. I am presuming the feed could tee into lower pipe of the cylinder coil and the expansion into the upper, but does it make any difference or do they have to go down to the boiler ? (Chris, my book hasn't arrived yet, hence the Q).

I have just taken out my primatic and replaced with a conventional indirect cylinder. Instead of a F&E tank I made a sealed by putting in a expansion vessel, gauge and filling loop. I first checked that my boiler could work on a sealed system.

You fitted an unvented cylinder or converted your own cylinder to an unvented

perhaps you should give us some more information before you blow the house up.