In article , ss
wrote:
On 07/05/2019 16:06, John Rumm wrote:
Remember that if its an upstairs rad, then the pressure at the RAD
could easily be half a bar (i.e. 15' of head) lower than that seen at
the boiler. Many boilers will work down to 0.5 bar, which could equate
to no nett pressure at all on the first floor.

That could be it, the rad in question was on 1st floor.

surely on a sealed system, the pressure will be the same throughout the
system.

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