On 2007-03-20, Wayne Whitney wrote:

But some "thermostatic" valves say they don't adjust for fluctuating
supply temperature, just supply pressure, e.g. some Deltas.

OK, I contacted Delta today for some clarification. The issue is that
Delta's thermostatic valves (17T series and 18T series) have a warning
in the manual that if you adjust the temperature of the hot water
supply, you may need to recalibrate the thermostatic cartridges. The
answer Delta gave me was that the valves are thermostatic with respect
to small fluctatuations in supply temperature (a few degrees) but not
in response to large fluctatuations in supply temperature (tens of
degrees).

Cheers, Wayne