How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

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Doctor.ventil
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How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von Doctor.ventil » 12.08.2018, 14:07

Good afternoon.

I just finished a bigger reconstruction of my house and decided to go for Homematic IP system. So I purchased 13 radiator thermostats (HMIP-eTRV-2) for each room, one wall thermostat (HmIP-WTH-2) to rule three radiator thermostats in my living room and one base unit (HMIP-HAP).

My idea was to let my electric boiler (it is Elektrisch Heizkessel, not jut watter heater) keep the circuit heated up so everytime any radiator thermostat asks for hot watter, it is ready in the circle... I have found in the manual of my electric boiler, that after reaching of a certain temperature in the circuit (in my case 60°C) the boiler will switch off all heating elements and the built-in pump is running after this moment for defined time (in my case it is set up to 10 minutes).

Unfortunately I was a bit naive in that, because my boiler switches off after reaching 60°C as read in manual, but the pump will run forever, because it is ruled by the signal of any kind of thermostat, I called the supplier of the boiler and was told this is a normal behaviour (obviously they are not ready yet for this kind of smart solutions, whicj either require a hot watter in circuit, or a certain way of switching off the boiler).

So my current solution is a cheap wall thermostat, which is mounted in colder room and set up to cca 28°C in order to keep the boiler up and running and have hot watter ready for radiotar thermostat in case of need.... nevertheles this is just a stupid back up solution and I believed there have to be something from homematic IP - so I discovered this: https://technikkram.net/2018/01/neuheit ... mematic-ip

Now to my question: Can above mentioned device (HmIP-WHS2) fulfill my needs, i.e. anytime any of the radiator thermostats asks for heat, this device will give a signal to boiler to switch on (it should send the same non-potential signal like a dummy wall thermostat, just on/off) AND anytime all radiator thermostats will be heated up and tell the message "no more heating needed", it will tell to boiler using same principal (on/off) to switch off, which will trigger it's pump to swich off after 10 minutes?

If not, any idea how to solve this issue?

P.S.if you have an idea, but don't feel comfortable enough to answer in English, I would appreciate also a German answer - I speak German, just not on the level to define my heating system...

Many thanks in advance and have a nice day :-)

tomi_cc16
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Re: How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von tomi_cc16 » 17.08.2018, 01:35

Hi this product is not released yet and people have no experience yet. I think it make sense in this case to ask eQ-3 directly about your scenario and post later their answer here.

Here some more Info from ELV (ELV and eQ-3 have the same owner).
https://www.elv.de/homematic-ip-2-fach- ... lagen.html

Doctor.ventil
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Re: How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von Doctor.ventil » 17.08.2018, 13:06

Hi.

Thansk for advice, just called with them and they confirmed (in english 8) ), that this element should do what I ask for - only problem is the lead time is 6-8 weeks, but if it works, it is definitely worth of waiting ;-)

Doctor.ventil
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Re: How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von Doctor.ventil » 23.12.2018, 20:36

I have just checked elv.de for delivery date for HMIP WHS2 and it has changed again to 9 weeks :(
Is this normal? Anyone knows where is the problem?

Thansk

tomi_cc16
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Re: How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von tomi_cc16 » 24.12.2018, 01:40

I’m afraid to say that sometimes for new eQ-3 products this became normal. Look for example on HomematicIP Wired which should be out by Q4 2018 and is now postponed to Feb/Mar 2019.

Product will come but sometimes it delays but this altogether 6 month delay is really long.

Sergo
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Re: How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von Sergo » 24.12.2018, 07:35

Doctor.ventil hat geschrieben:
12.08.2018, 14:07
P.S.if you have an idea, but don't feel comfortable enough to answer in English, I would appreciate also a German answer - I speak German, just not on the level to define my heating system...
Take a look on my workaround for the similar challenge viewtopic.php?f=49&t=46514&start=30#p471029

blueznl
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Re: How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von blueznl » 30.12.2018, 23:22

Could you explain the behavior of the boiler a little bit more in detail? I'm trying to understand what you are writing, and sorry, I don't understand :-)

(I'm Dutch, so it might be me.)

> My idea was to let my electric boiler (it is Elektrisch Heizkessel, not jut watter heater) keep the circuit heated up
...
> is ruled by the signal of any kind of thermostat, I called the supplier of the boiler and was told this is a normal
> behaviour (obviously they are not ready yet for this kind of smart solutions, whicj either require a hot watter in
> circuit, or a certain way of switching off the boiler).

What do you mean with 'the pump always keeps running'? If the thermostat contact opens again, shouldn't it stop after 10 minutes?

I'm confused.

Sergo
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Re: How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von Sergo » 31.12.2018, 00:32

Sorry for creating any possible confusion.
Let me get back to basics: usually, heating system with gas heater include two key elements - heater itself and water pump.
In my case, with Junkers Euroline, both in the same module. So, operational logic is a bit different compare to setup with independent heater & pump.
In my case, by design, heater could operate in two modes:
- without external thermostat: in this case water pump continuously pushing flow through heating system and controlling temperature of incoming water. Once it lower then set temperature - heater engaged until incoming temperature is ~= outgoing. This not really effective mode, I would consider this as an “emergency operation”.
- with external thermostat: in this case there is variations on type of thermostat used, but for our discussion let’s limit this to standard, single dry contact?
In this case: Homematic Thermostat is supposed to collect information from radiator actuators paired and drive On/Off decision to switch on gas heater. Because we usually have above single thermostat, this raising question about how to merge them and make logical call to gas heater. So far there is no ready solution for this common setup from ELV, IMHO. And not clear if they even prioritizing this typical use case high enough.
As an temporary solution, you seen my proposal - it works. There few known weak sides:
- because direct connection with battery based switch does not work by design, this solution works only via program on CCU side
- I went for powering on battery based switch from AC, there is potential issues - but all fine for second month

What next? I’m waiting for my order of HmIP-WHS2 or any reliable information about this device. Most likely HmIP-WHS2 will not cover our use case, IMHO :? And I will switch to similar setup, but based on few HmIP-PCBS (as suggested by Sammy) connected in parallel. This will require some additional clarification on how to obtain dry contacts with HmIP-PCBS.
Sorry, looking on all what I wrote here.. sorry, if this do not help ;)

tomi_cc16
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Re: How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von tomi_cc16 » 31.12.2018, 00:52

Hi,

FYI - on eQ-3 website the DE/EN manual for HmIP-WHS2 is offline but you can still find it here:
https://files.elv.com/Assets/Produkte/1 ... UM_web.pdf

It's Version 1.0 from 08/2017 - maybe there will be an update when they will start shipping

Doctor.ventil
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Registriert: 12.08.2018, 13:29
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Re: How to switch on the Electric Boiler (Elektrisch Heizkessel) with thermostatic radiator heads?

Beitrag von Doctor.ventil » 02.01.2019, 21:57

Sergo hat geschrieben:
24.12.2018, 07:35
Doctor.ventil hat geschrieben:
12.08.2018, 14:07
P.S.if you have an idea, but don't feel comfortable enough to answer in English, I would appreciate also a German answer - I speak German, just not on the level to define my heating system...
Take a look on my workaround for the similar challenge viewtopic.php?f=49&t=46514&start=30#p471029

Hi Sergo.

Thanks, I am monitoring all the interesting stuff you do, but although I went through several semesters of programming, database handling, etc., I am always looking for the working solution from manufacturer, which WHS2 seems to be (and I am really lazy to get too deep in to CCU3 programming :-) ).
I am using now some workaround with dummy cheap thermostat set to 24-25° C to keep the boiler running with one nearby radiator, which is without smart thermostat head. It might sound completely inneficient, but to keep it running, boiler switches between 0 and 2kw just to keep the system heated up. This radiator is in small corridor (4m2) close to bathroom, where I keep the door open and so far it works quite good.

I think I will just wait, I just hate when being cheated by false delivery expectations...

Anyway thanks a lot for the great job you guys do, especially Tomi_cc16 and you Sergo ;-)

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