Roger wrote:
The message .com
from contains these words:
Mogweed wrote:

I have a Baxi Bermuda 552 back boiler which gives pumped central
heating and
(what I believe is termed) gravity hot water, ie, when system is
set
to hot
water only, the upstairs rads get warm as well.

no, thats called a plumbing ---up. Your upstairs rads are on the
hot
water circuit.

More likely that the upstairs rads are getting gravity circulation
when
the pump is off.

Spose it depends how hot they get with HW on and CH off. But whatever
the deal I'd suggest some food dye for the OP, to ensure you dont put
nasties in your water supply.

NT