If D from BC were a plumber:

You're always wrong, AlwaysWrong. That being a fact, I'm pretty smart.

You never were good at thermo, DimBulb. That's why you're known as DimBulb.

The temperature won't change, AlwaysWrong.

mpm Inscribed thus:

Can you confirm that the water pressure for both hot and cold feeds to the shower/mixer tap are the same.

Not without tearing the wall apart. With the showerhead attached, I can confirm that I get about the same flow out of each (hot or cold), but beyond a certain valve opening, the water flow out of the showerhead appears constant. In other words, it doesn't get a stronger stream if you open the hot and cold valves all the way, vs. say maybe 1/4 of the way or 1/2 way.

So, either the showerhead has a flow restrictor built in (likely?), or the showerhead itself behaves as a flow restrictor.

It is a two-valve systems, by the way. Someone above is under the impression it's a single-valve. It's not. Hot on left, cold on right. etc..., etc...

That's a pretty cool idea. It's like the best of both worlds. Energy savings, but not at the expense of possibly having no hot water (i.e., forgetting to turn it on, or a timer setting that's occasionally inappropriate for actual demand use).

The only way I see to make it better, is to have it heat up for morning showers (or whenever) without having to run it first. Sort of like an artificial intelligence hot water heater. It could "learn" from prior use.

mpm Inscribed thus:

No you don't want to do that. ;-)

Mmm. If the water pressure is the same in both hot & cold pipes to the valve that only leaves partial blockages or that the temperature is changing the behavior of the mixer valve.

Yes I agree. That would be consistent with the flow limiting even though the valve is fully open. Mine behaves in exactly the same way.

My hot water system has an intelligent controller in it. If demand for water exceeds a level in a period of time. It'll increase the temperature level and maintain it for ~ 2 hours after non use.

From there on, it keeps it at a lower level to save energy.

So, if I want real hot water when showing, I first need to run the shower for a bit to force the burner to come on. And then, every one in the house can take their shower with plenty of real hot water as long as they do it with in 2 hours each. After that, the system then simply measures the time of refills and if there is a large gap, it just simply keeps the water warm..

It does save nicely on fuel oil.

OK, it is but in fairness, the pressure does exhibit small fluctuations in such circumstances. It could act as a surge accumulator in rare cases.

mixing

The uncommon behavior you report is usually linked to a pump on the hot water side. But then it is usually most of the time rather than occasionally. Could there be a "sometimes" pump involved?

this!'

but

honest=20

with=20

each=20

to=20

superior=20

Leave it in that thread.

Well said, Rog...

Now, that is what one would call pipe dope.

John Lennon called it "Fixing A Hole".

D from BC must be bald from all these years of pulling his hair out worrying about what *we* all believe in. (Yes, y'all, I said 'we all')

All you have done is a fine job of secluding yourself.