I can attest that the installation of a hot water recirculating pump (and sensor valve) does work. Hot water very quickly for the morning shower, really! However,.

The 'however' is that I find that while the pump is on (in the AM for ~1-1.5 hr.), the hot water and cold water mixing in the shower valve is VERY, VERY sensitive - cold to scalding in just a few degrees of rotation. This is much different than before the pump was installed or if the pump is turned off. It is almost like the pump is boosting the pressure too much, but I am told that these pumps are not supposed to be that powerful. I do not want to give up on the concept, but at this point it is not acceptable. Thanks.

What's the brand name of your shower valve. Has it got a temperature control or a scald guard in it? Regards, Tom

No, it does not. It is old (20 years). I am considering a new valve (Moentrol?) anyway due to pressure fluctuations from other deviations, e.g. flushes. I guess that I just never expected the inclusion of the hot water recirculator to amplify a problem that I never really had before the inclusion of the pump. Can I assume that you recommend the addition of a better control valve, also? Thanks,