Tecalor THZ Heatpump

German version: Tecalor THZ Wärmepumpe

This article describes how to connect to a Stiebel Eltron / Tecalor THZ/LWZ 303/304/404 heatpump and to read and write settings from and to the heating.

For better understanding: Tecalor is the end customer brand of Stiebel Eltron. In the following the system will be called "THZ"

Tested are Software Versions 4.19, 4.39 and 5.39. Older versions may work but there's no guarantee for. NOTE: This manual is for persons who are familiar with electronics. The author and the developer are not liable for any damage and there's no warranty.

Connection to the heatpump

Local via RS232 or USB

The THZ has two interface which can be used for a connection.

• One serial interface behind the right door which can be used with a MNL-SG3 Plug
• One USB interface on the electronics board which can be used with a TYPE-B USB cable.

Warning!!! The USB interface is on the back side of the electronics board behind the coverage wich is behind the right door. Do not connect the USB while the system is powered on! Before removing the coverage you have to power off the complete heatpump!!

The baud rates may vary based on hard- and software release between 9600 and 115200 for RS232. For USB it's always 115200 baud. More information how to connect to the heatpump with RS232 can be found here: Robert Penz Homepage

Remote connection with Ser2Net

If the FHEM server is not near the heatpump you can connect with Ser2Net. This will provide a virtual serial interface on a TCP-Port

Installation Ser2Net on Linux

To install Serial-Port-Server Ser2Net just follow these steps:

sudo apt-get install ser2net

in /etc/ser2net.conf (/dev/ttyXXX)

2003:raw:500:/dev/ttyUSB0:115200 NONE 1STOPBIT 8DATABITS

The port can be chosen on your own as long as it's still unused.

Tested Host-Systems

This module was tested on FritzBox, nas-qnap, Raspberry Pi and MacOS.

Definition in FHEM

Direct RS232 serial or USB

define Mythz THZ /dev/ttyUSB0@115200 # or (/dev/ttyXXX)

attr Mythz interval_allFB 300 # Internal Polling Intervall 5min

attr Mythz interval_history 28800 # Internal Polling Intervall 8h

define FileLog_Mythz FileLog ./log/Mythz-%Y.log Mythz

If you don't define the attributes interval_allFB and interval_history (or they are 0), the internal polling is disabled. Sure you can also poll with the "at" command outside the module:

define Mythz THZ /dev/ttyUSB0@115200 # or (/dev/ttyXXX)

define atMythzFB at +*00:05:00 {fhem "get Mythz allFB","1";;return()}

define atMythz09 at +*08:00:00 {fhem "get Mythz history","1";;return()}

define FileLog_Mythz FileLog ./log/Mythz-%Y.log Mythz

Over network with Ser2Net

define Mythz THZ 192.168.0.244:2003

attr Mythz interval_allFB 300 # Internal Polling Intervall 5min

attr Mythz interval_history 28800 # Internal Polling Intervall 8h

define FileLog_Mythz FileLog ./log/Mythz-%Y.log Mythz

Readings

If the connection to the heatpump was successful you should see readings like allFB, firmware, history and some settings like holiday and pXX parameters.einige PXX Werte angezeigt werden.

allFB

Contains all actual values like water and gas temperatures, fan states, pressures, ...

firmware

Shows the firmware release.

history

Contains information to operating hours, e.g. the compressors operating hours.

holiday-Werte

Here you can see the settings of the holiday configuration of the THZ. These are used to override the day setback for the give time. You can change the holiday settings with set.

last10errors

Reads the last 10 errors and shows it.

pXX-values & program-values

The pXX & program values are settings like the heating circle, fan states, dhw programs and so on. All pXX and program valueas can be changed with the set command. NEW: Now the fanstage-inlet and outlet volumes are read- and writeable.

party-time

This parameter sets the party time. While this time range the fan state will change to the in p99FanStageParty stage.

Plots - graphical views

This shows you how to create plots from the heatpump readings.

Example

Assuming we want to read and plot the outside_temp and the dhw_temp from the allFB reading:

Creating the plot in fhem.cfg:

define Plot_Temp SVG FileLog_Mythz:thz:CURRENT

attr Plot_Temp room Heizung

This will setup the plot without any data and maybe with an error message. Klick on the plot-name to open the plot config windows. Here you enter the details.

Most important are now the input fields

Below the input mask you find the according readings to Mythz, including allFB.

allFB will like like this:

2014-03-02_13:07:49 Mythz allFB: outside_temp: 3.8 flow_temp: 26.5 return_temp: 27.2 hot_gas_temp: 32.1 dhw_temp: 43.4 flow_temp_HC2: -60 evaporator_temp: 5.3 condenser_temp: 27.4 Mixer_open: 0 Mixer_closed: 0 HeatPipeValve: 0 DiverterValve: 0 DHW_Pump: 0 .................output omitted

To find the right input value just count the space seperated data. So the value for outside_temp is 5 and dhw_temp is 13 as these are the positions they are on. This number will be entered into the input field to create the plot with the chosen data.

More information to Creating Plots

extract single values from readings

To separate values to from the "big readings" like allFB or history you can use a userReading.

Example:

attr Mythz userReadings OutsideTemp {(split ' ',ReadingsVal("Mythz","allFB",0))[1]},

FlowTemp {(split ' ',ReadingsVal("Mythz","allFB",0))[3]}

More information to userReadings can be found in the CommandRef

Notes

• A full refresh (of all parameters) is done only at systemstart, very very slowly (not to decrease performance of FHEM), and takes ca 3 or 4 minutes. After that the intervall polling of allFB and History register should start.
• If the FB-intervall or History-Intervall attributes are lower than 3 minutes, there clould be a concurrency. But that shouldn't cause any problems.

known Problems

In the FHEM Log you will find messages like this when using Ser2Net:

2014.03.02 09:41:09 1: 192.168.178.50:2003 disconnected, waiting to reappear

2014.03.02 09:41:09 1: 192.168.178.50:2003 reappeared (Mythz)

This problem is not solved until now.

Release History

v0.067

Module first implemented in FHEM

v0.068

new command for party

v0.069

added German CommandRef

v0.070

BugFix in status bits

v0.071

Bugfix, undefFn improved

v0.072

• all programHC1*, programHC2*, programFan* and programDHW* have been implemented with get and set
• inside_temp has been added to the end of allFB
• connect/disconnet bug related to ser2net has been extremely improved: max one retry per second

Links

Launchpad Heatpumpmonitor

Thread in the FHEM-Forum