In article ,
Keith2.0 wrote:
On Sun, 31 Aug 2008 14:23:45 +0100, "John"
wrote:

A friend (as in the Flue question) has had a combi fitted upstairs (new
flue through roof). The fitter did a great job, but the electrician
needs to come in 2 weeks after my friend returns from holiday -
therefore it is running without a room stat at present.

He is concerned about the noise and some of his family have switched it
off at the spur unit. My instinct is that this is a bad idea as it
could upset the pump or fan control. However, what is the noise - is
it a fan?

It could be the pump. As the thermostatic valves on the radiators close,
the pump faces increased resistance (or something). It will start off
quiet and get louder as the house heats up if this is the case.

Assuming a modern Viessmann (I only have details of my one) the pump is a
vary speed unit so will adjust. It also has a built in bypass loop.

The thermostat circuit could be low voltage in which case you could do
it yourself

Mine uses a room temperature sensor rather than a thermostat. So all
adjustments are done from the programmer. But it has the option to use a
conventional one.

--
*Warning: Dates in Calendar are closer than they appear.

Dave Plowman London SW
To e-mail, change noise into sound.