HC2 - Radiator valves and ON/OFF command to the heater

[mzini 0]

Hello to all. I'm new in the forum and I wish to buy Fibaro HC2.

I'm still benchmarking with MCV Vera3, but I think HC2 will win because of:

1) Simplicity in accomplishing the "normal" tasks,

2) HW aesthetic

3) GUI aesthetic.

4) GPS user localization (and, if I understand correctly, the ability to do task in function of the user distance from home)

The pro for MCV Vera3 seems to be:

1) the fact you can write code to do anything, but it seems in despite of ease of use...)

2) WI-FI (I haven't decided yet where to place the control center...

3) more compatibility with Z-wave device (accordingly to this page:

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)

Any suggestion to complete the banchmark will be appreciated even if I think there is some thread about this somewhere in the forum.

But at the moment I have some technical question.

Please forgive me if the question is trivial, but I'm a novice.

I'm planning to buy HC2 and 10 Danfoss Living Connect Z to control all the radiator in my home.

I think that my home heater has a bypass and could work without problem even if all the valves will be closed, but I don't want the heater will continuously start (even if only for a few seconds) when all the valves are closed. So, the question is:

can I set a configuration that will close the switch of a SECURE SSR303 (

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) when at least one valve is open and to open the switch (stop the heater) when all the valves are closed?

I plan to install the SSR303 in place of the currently used thermostat.

May be there is a cheaper solution to stop the heater? And/Or some other device (simple switch) that do not need an external power supply?

Is it possible to view from HC2 which valves are open and wich ones are closed?

Does the valve operate also in partial opening (depending on the difference between read temp and set temp) or they work only in ON/OFF mode?

I have many other questions about light switches and for managing AV devices via IR... but I think I will open new threads for them...

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Thank you very much for your help!

Bye

Mauro.

[martinpreiss 4]

Im solving similar problem.

The Danfoss can't report and won't report if it's closed or opened. That's a problem. The Danfoss valve has it's own intelligence when to open and when to close and how much. It's not just On/Off it's linear (or logarithmic don't know) but gradual for sure.

You can use the bypass for turning on and off the heating. When you install a spring switch on that bypass. This is easiest...mechanical and should work...

I want to use Universal Sensor with 3 temp sensors. 1 sensor for outside temperature, 1 for OUT circuit FROM the boiler and 1 for return IN circuit TO boiler. And 1 relay for On/Off the whole system, one relay turning on/off heating segments and 1 relay for pump. Then write a Virtual device, or Scene (a very complex) that will do a ekviterm heating. Based on outside temperature, it will set water temperature on the OUT circuit and will monitor the IN segment, if the return water will be the same as output water, then all valves are probably closed, so you can turn off the pump and heating...

But seems monstrous....but will be the best energy saving system ever...

Or you can compare temperatures between Danfoss and Thermostat in a room....

If danfoss temp is bigger then actual temp THEN turn on heating

if danfoss temp is smaller then actual temp THEN turn odd heating.

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[jnevestdl 1]

Good question. It would be nice if someone could explain this to us.

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[alecon 2]

I'm evaluating a similar solution; I think I'll put Danfoss on any radiator and connect them to HC2 to read and set C° values

The SRT322 receiver will be dedicated to start/stop the heater and the thermostat will be fixed in the colder place of my house.

This will cause the danfoss valve will close the single radiator if setpoint is reached while thermostat is ON.

At the end I've your same problem; if all danfoss valve are closed but thermostat is still ON the heater should STOP.

Hoping someone else has a solution.

[richo 4]

It's better to have the controller based on the external temp sensor - the boiler will set the water temperature based on the current temp. However not all boilers support it. WIth Danfoss's you don't need additional thermostat in that case neither you need a switch to turn off the boiler.

[mzini 0]

This will cause the danfoss valve will close the single radiator if setpoint is reached while thermostat is ON.

At the end I've your same problem; if all danfoss valve are closed but thermostat is still ON the heater should STOP.

Hoping someone else has a solution.

Thank you to all.

I see it's not a simple task.

and I am very disappointed 'cause I thought that by spending € 1500 I had some help

The main problem is that the Danfoss don't report the HC2 its state.

May be that with stellaz (

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) it would be possible to get the valves status and to setup in HC2 an OR statement that can sitwch off the heater opening a switch like SSR303?

[petergebruers 1,268]

I 've owned a stella-z for two weeks and have send it back to the supplier... Fibaro support confirmed to me that the device is currently "not supported".

[hvb83 1]

That's a bit harsh isn't it? Danfoss is completely separated from Fibaro and I had a couple of questions in regard to heating to them last week and they provided me with a taylor made script within a couple of hours.

The Danfoss is simply not able to report it's state or measured temperature to HC2 (or any other controller for that matter). That's a flaw in design from Danfoss' side in my opinion. I have it running for the past week now, and I must say I'm very happy with it up to now. Even though there haven't been big deviations in outside temperatures, it seems the system controls the temperature quite well..

But I don't understand the problem completely I think. If set wel, the boiler will be switched off by the heating panel almost at the same time when the room has reached the desired temperature and the Danfoss should close the valve completely.

Since it is hardly the case that these moments match exactly, it is very wise to have some radiators that are always opened (without a thermostat on them, just a regular valve) or with a bypass somewhere in your system.

[mzini 0]

But I don't understand the problem completely I think. If set wel, the boiler will be switched off by the heating panel almost at the same time when the room has reached the desired temperature and the Danfoss should close the valve completely.

Thankyou very much hvb83. But....

I would like that all the radiator will be controlled by a (thermostatic Radiator Valve) TRV (and by the HC2), managing several different zones with on heater. And I would like the heater will be OFF when all valves are closed.

I think the heater has a bypass (I think so because the heater manual ssy it can work with TRV by shortcircuiting the thermostat imput). So when all valves are closed I think the heater can stop heating and stop the pump because the returnig water is at the same temp of the water pumped out, or however greater of a set point). But in this mode I have two problems:

1) The heater will go on (heating unit and pump) every x minutes (even if the valves are still closed, because the water temp in the bypass will lower)

2) If on valve will open the heating will start heating unit and pump only after x minutes.

The lower x means a lot of heater starts (even if for a short time) without real need (and I'm afraid this will lower the heating life). The higher x means more delay when some room needs heating.

I think that my heater can be set to have the pump always on. In this case I don't have the problem 2), but I have the downside effect of having a pump running from september to march without stopping... Will it die? How much will it cost in electricity bill?

If I could stop the heater using the thermostat input (piloting a switch depending on the valves state) all the problems can be solved.

Hope I've been able to correctly explain my needs.

Thank you for your interest and help.

[antamaga 0]

During the times when the heating panels command the valves for boiler and pump should keep the hot circuit up to the collector otherwise you'll waste a lot of energy to heat the pipe again, and when the circuit is hot the boiler is turned off until further heat demand. No need to turn off the boiler and / or pump in working hours established if the thermostatic valves at the same time they do their job. It 'important that in front of the radiator there is a tent, this work would hurt the thermostatic valve.