On Tue, 29 Nov 2005 11:56:55 -0000, "Mark Hewitt"
wrote:


"Andy Hall" wrote in message
.. .

1) Use the bathroom radiator as a bypass for the boiler. If you look
at your system, you may find a pipe between the flow and return
from/to the boiler before the motorised valve(s) with something like a
radiator lockshield valve on it. The purpose of this is so that if
the CH and HW thermostats are satisfied and the boiler is in full
burn, there is a path so that the pump can continue to run and
dissipate the heat.

This is how my towel rail is configured and I wish it wasn't! When it pumps
through the towel when all other rads are off it makes quite a noise and
stops me from sleeping at night.


You may be able to alleviate this by changing the pump to a Grundfos
Alpha.

These automatically back off their power as the flow resistance
increases, which I suspect here is the reason for the noise.


--

..andy