How TRVs actually work?

That confused me till I realised your sq root only applies to (1.0/0.3), not 7.1*60/1000. But shouldn't it be 7.2?
Presumably the 0.3 bar is the pressure drop across the TRV (not sure what you mean by dynamic head, that's usually V^2/(2*g))

Not with you. If it's 1.2 each isn't that 2.4m? Earlier you said 3m = 0.3 bar across the TRV, unless I'm misunderstanding you test.
BTW, TVR is (or was) a sports car :giggle:
No, I will correct this, it was 7.1LPM at 0.3bar. What I mean by the dynamic head is the head available at the TVR when flowing 7.1LPM, with no flow, the head, which I call the static head was 0.55M. The dP through the TRV at a flowrate of 1.43LPM should be (1.43/7.1)squared x 3M, 0.12m, TRV+L/S, 0.24M, not 0.44M (will edit above post).
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The Heat Geek knows best??.

View attachment 326135

Balancing heating systems is simply making sure all the radiators or emitters heat up evenly

At least we have someone putting forth a basis!

It's a start.
But it's wrong.

It makes huge assumptions.

What you actually want is rooms heating up as quickly as possible in a system which is as stable as possible.
Quite difficult to do. Nothing to do with making the rads heat up in sync with the lowest common denominator.

For the post i was referring to,
Modern pumps are absolutely not designed to provide a constant head in a normal system (CP). They are PP pumps designed to provide variable flow to reduce energy consumption.

Dunno wtf 11-12c temp drop is relevant? I doubt the poster couldn't explain either.


Everything just missed the point.
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The greater the dT for any given flow temperature the lower the rad output.
A normally rated T50 rad will emit 100% output with flow/return temps of 75C/65C, dT,10C. (assumes 20C rom temperature)
A normally rated T50 rad will emit 87.2% output with flow/return temps of 75C/55C, dT,20C. (assumes 20C rom temperature)
With a low flow temperature from a Heat Pump or from a WC Boiler the dT is kept as low as possible to get the maximum possible output.
The rad above will emit 25.5% of rated output with flow/return temps of 40C/35C, dT,5C.
It will only emit 20.9% of rated output at flow/return temps of 40C/30C, dT,10C, or 82% of the 5C dT rad.

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