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Re: Air Vent at boiler. Necessary with Air Sep?
Like.
This will remove air from the system as the system operates with the help of the laws of Physics. But each radiator convector must have at least some water in it so that water can flow and can absorb the air into the water and carry it to the hottest, lowest pressure location where there is an air separator.
I like your diagram
Re: Viessmann vitodens 200 wb2 11-44 boiler problems
this is the instlal sheet that would come with a replacement lgm29
I am pretty sure they still had an older form of what they call lambda pro today, on those boilers. so the gas valve is most likely non-adjustable. but you would want to make sure both units were set to the same fuel type. Also there is a water pressure sensor inside the unit which can shut it down if water pressure is too low.
GGross
Re: Viessmann vitodens 200 wb2 11-44 boiler problems
The donor control board may have been configured differently (DIP Switches and electronically stored parameters).
109A_5
Re: Air Vent at boiler. Necessary with Air Sep?
Depends on the circulator location. If you have the air sep on the supply (HOT) side of the boiler piping and the circ is pumping away from the air sep, AND you attach the Ex-60 expansion tank and boiler fill valve at that same point, you will actually eliminate the air problem. It all has something to do with the Physics of Water and Boyle's Law of dissolved gasses. Long story short… Hot water and low pressure will release dissolved air. Put a vent there and all the air in the system will get absorbed in the water and released at the air sep. (ask me how I know this)
Re: (2025) Smart and/or programable TRVs that function as a flow rate valve and not a thermostat
Theoretically, of course, of course, it's quite possible. In practice, there are some rather interesting difficulties. They lie both in the control logic which is to be followed and in the physical construction of the valve.
Not to say it can't be done. I just don't know of any which do.
Re: (2025) Smart and/or programable TRVs that function as a flow rate valve and not a thermostat
Is this a hot water, or steam application ?
Caleffi has a product with adjustable Cv, in the European market. Not for steam however
hot_rod
Re: (2025) Smart and/or programable TRVs that function as a flow rate valve and not a thermostat
0-10V zone actuator with 0-10V thermostat. If you are into smart home, there is a lot of 0-10v output devices as they are used for dimmers, combined with a room sensor and a bit of coding, you can do your own controls.
https://www.caleffi.com/en-us/thermo-electric-control-valve-actuator-24v-source-0-10v-prop-actuation-nc-6565-caleffi-656524
Kaos
Re: (2025) Smart and/or programable TRVs that function as a flow rate valve and not a thermostat
So it would seem that the hardware exists — the modulating valves (0 to 10 volt). Excellent. And, of course, the sensors, also 0 to 10 volt thermistors.
Which leaves the problem… the software and control integration. Whether you need to run a separate cable to each radiator or not is somewhat debatable; I would at least look into the possibility of a single 4 or more wire (probably Cat 5 or better) cable capable of feeding a digital command and feedback signal to a central processor but also capable of feeding the required power and ground to each unit. I suspect the computing power available in a Raspberry Pi of some flavour would be quite adequate.
The Raspbeerry Pi community is open source — and has extraordinarily wide interests, so it is entirely possible that there may be some code bits which would be usable as part of the programming.