6 May 2004
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United Kingdom

I'm removing the CH part of my log burner setup, but I want to keep the DHW side. The current system is incorrectly plumbed so effectively it's starting again.

What I need to know before I get a plumber started is how the system should be laid out. The back boiler has a max 5.5kwh output (but in reality with logs and normal conditions it will never reach this). So I plan to have 1 radiator and the DHW in a thermosyphon.

Now I know all the piping for the DHW (and that is correct as it is) but my confusion is where to connect to the in and out to the radiator relative to the heights of the in/out of the heating coil in the cylinder.

Should the radiator in be above the height of the cylinder in?
Should the radiator out connect back to the back boiler below the return from the cylinder coil?
Should the radiator be connected with hot in at the top, cold out at the bottom (as opposed to two bottom connectors on a normal rad)?

At the moment I think I need to take a spur from the expansion pipe above the cylinder "IN" and above the height of the radiator. This then drop to floor level, goes under the floor, up the side of the radiator in the top valve. The OUT from the rad drop to floor level and connects on the return to the back boiler below the return from the cylinder.


Just as an aside, I'm keeping the DHW on the old boiler as the new boiler is electric and it does not make sense to use it (over and immersion) to heat the water, especially when we still use the log burner at weekends.
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