[jason20]

Can anyone help me please?

I have wet UFH installed in my conservatory and study with a standard boiler and vented gravity fed HWT. The plumber who installed the UFH maintained the Y plan heating system (don't know why he chose not to convert to an S plan) and took a feed from below three port valve to the UFH manifold. He also installed a two port valve between the new feed and the three port valve (presumably to close of the otherwise open valve if the HW or CH was not calling for heat). There is also a pressure release valve of some sort between the new feed and the return pipe which come out of the hot water cylinder. Sorry about the terminology but I hope that makes sence.

The UFH is therefore independant of the HW and CH. However if I use the UFH alone the pipework in the airing cupboard where the HWT is held, roars and wooshes. It is fine when the HW or CH are in use but I can't use the UFH alone becasue it's so noisy. I belive this is called kettling - too much heat being generated by the boiler which is not disipated by the UFH manifold.

I thought that's what the presure vaulve was for (or is it just boiler overrun?).

Can anyone suggest how I can resolve this problem. The guy from British Gas didn't have a clue!!

[Tat]

The operating temp. of UFH needs to be low 25-30 deg. C a thermostatic regulating valve will cope with that, but if the Htg & DHW is OFF! you are pumping all the htg pump outlet into the UFH, are you dragging air down the open vent, I think UFH systems should be used on sealed systems!