In version 0.113 of Home Assistant it will be possible to send RfxTrx event codes with the new rfxtrx.send service.
I just tested this in the beta release and this works great.
First capture and test the needed command code for each button of the fireplace remote in the Rfx Manager application. And copy this code so that it can be used in service call.
So I think this topic can be closed soon.
Here is it :
@aerodolphin Due to having to use Ethernet, I am currently controlling our fireplace using ESPHome and an ESP32-POE with 433MHz transmitter.
In case it’s of any help, below is my configuration YAML in ESPHome. As you can see, I have four commands (power on/off, and flame up/down). Each command is defined as a switch (i.e. 433MHz transmitter sends the code to the fireplace), as well as a binary sensor (HA detects when the original remote’s buttons are pressed, and also when the 433MHz transmitter sends the codes). The binary sensors are not really necessary, but I really wanted to make sure I was able to go full circle (due to being a control freak 
).
esphome:
name: esp32_poe_2
platform: ESP32
board: esp32-poe
ethernet:
type: LAN8720
mdc_pin: GPIO23
mdio_pin: GPIO18
clk_mode: GPIO17_OUT
phy_addr: 0
power_pin: GPIO12
logger:
api:
ota:
remote_transmitter:
pin: GPIO32
carrier_duty_percent: 100%
remote_receiver:
pin:
number: GPIO33
inverted: True
mode: INPUT_PULLUP
filter: 200us # default = 10us
idle: 4ms # default = 10ms
binary_sensor:
# Fireplace
- platform: remote_receiver
name: Fireplace On
rc_switch_raw:
code: '1010011110011'
protocol:
pulse_length: 380
sync: [45, 1]
zero: [1, 2]
one: [2, 1]
inverted: true
filters:
- delayed_off: 1000ms
- platform: remote_receiver
name: Fireplace Off
rc_switch_raw:
code: '1010011110111'
protocol:
pulse_length: 380
sync: [45, 1]
zero: [1, 2]
one: [2, 1]
inverted: true
filters:
- delayed_off: 1000ms
- platform: remote_receiver
name: Flame Up
rc_switch_raw:
code: '1010011111011'
protocol:
pulse_length: 380
sync: [45, 1]
zero: [1, 2]
one: [2, 1]
inverted: true
filters:
- delayed_off: 1000ms
- platform: remote_receiver
name: Flame Down
rc_switch_raw:
code: '1010011111101'
protocol:
pulse_length: 380
sync: [45, 1]
zero: [1, 2]
one: [2, 1]
inverted: true
filters:
- delayed_off: 1000ms
switch:
# Fireplace
- platform: template
name: Fireplace
icon: "mdi:fireplace"
optimistic: true
assumed_state: true
turn_on_action:
# - remote_transmitter.transmit_raw:
# carrier_frequency: 433MHz
# code: [ 380, -380, 380, -760, 760, -380, 380, -760, 380, -760, 760, -380, 760, -380, 760, -380, 760, -380, 380, -760, 380, -760, 760, -380, 760, -17200 ]
# repeat:
# times: 120
- remote_transmitter.transmit_rc_switch_raw:
code: '1010011110011'
protocol:
pulse_length: 380
sync: [1, 45]
zero: [1, 2]
one: [2, 1]
repeat:
times: 120
wait_time: 10ms
turn_off_action:
# - remote_transmitter.transmit_raw:
# carrier_frequency: 433MHz
# code: [ 380, -380, 380, -760, 760, -380, 380, -760, 380, -760, 760, -380, 760, -380, 760, -380, 760, -380, 380, -760, 760, -380, 760, -380, 760, -17200 ]
# repeat:
# times: 60
- remote_transmitter.transmit_rc_switch_raw:
code: '1010011110111'
protocol:
pulse_length: 380
sync: [1, 45]
zero: [1, 2]
one: [2, 1]
repeat:
times: 60
wait_time: 10ms
- platform: template
name: Flame
icon: "mdi:fire"
optimistic: true
assumed_state: true
turn_on_action:
# - remote_transmitter.transmit_raw:
# carrier_frequency: 433MHz
# code: [ 380, -380, 380, -760, 760, -380, 380, -760, 380, -760, 760, -380, 760, -380, 760, -380, 760, -380, 380, -380, 380, -760, 760, -380, 760, -17200 ]
# repeat:
# times: 60
- remote_transmitter.transmit_rc_switch_raw:
code: '1010011111011'
protocol:
pulse_length: 380
sync: [1, 45]
zero: [1, 2]
one: [2, 1]
repeat:
times: 60
wait_time: 10ms
turn_off_action:
# - remote_transmitter.transmit_raw:
# carrier_frequency: 433MHz
# code: [ 380, -380, 380, -760, 760, -380, 380, -760, 380, -760, 760, -380, 760, -380, 760, -380, 760, -380, 760, -380, 760, -380, 380, -760, 760, -17200 ]
# repeat:
# times: 60
- remote_transmitter.transmit_rc_switch_raw:
code: '1010011111101'
protocol:
pulse_length: 380
sync: [1, 45]
zero: [1, 2]
one: [2, 1]
repeat:
times: 60
wait_time: 10ms
For testing purposes, I include all of these entities in a Lovelace card:
I have some photos of the hardware in another post (bottom half of the post):
Based on the message from @Marsman, I have successfully added controls for the Mertik G6R-H4T5 to Home Assistant. After capturing the command codes with RFXmgmr, I have added the following code to configuration.yaml:
input_boolean:
haard_switch:
switch:
platform: template
switches:
haard_switch:
value_template: >
{{ is_state('input_boolean.haard_switch', 'on') }}
turn_on:
- service: input_boolean.turn_on
entity_id: input_boolean.haard_switch
- service: rfxtrx.send
data:
event: 0842010C005A0F0177
turn_off:
- service: input_boolean.turn_off
entity_id: input_boolean.haard_switch
- service: rfxtrx.send
data:
event: 08420118005A0F0074
icon_template: >-
{% if is_state('switch.haard_switch', 'on') %}
mdi:fireplace
{% else %}
mdi:fireplace-off
{% endif %}
Hi Corne. Is it possible to supply me all the events from all the buttons. My remote broke and I would like to control my fireplace by home assistant instead of replacing the remote witch is really expensive and I already have a rfxcom. I can pair it as a new remote.
Thanks
Hi Tekno,
I hereby send you my configuration in HA. I have also added the signal information for Up and Down, however I don’t use these buttons. Good luck!
input_boolean:
haard_switch:
switch:
platform: template
switches:
haard_switch:
value_template: >
{{ is_state('input_boolean.haard_switch', 'on') }}
turn_on:
- service: input_boolean.turn_on
entity_id: input_boolean.haard_switch
- service: rfxtrx.send
data:
event: 0842010C005A0F0177
turn_off:
- service: input_boolean.turn_off
entity_id: input_boolean.haard_switch
- service: rfxtrx.send
data:
event: 08420118005A0F0074
icon_template: >-
{% if is_state('switch.haard_switch', 'on') %}
mdi:fireplace
{% else %}
mdi:fireplace-off
{% endif %}
Thanks. I will let you know if it worked.
I just found out that the Mertik Maxitrol has a (expensive) WiFi module that communicates using a serial interface with the gasblock controller (G6R-R4AU). So the WiFi module is nothing more than a protocol convertor.
If someone does have the WiFi module, we could monitor the serial connection and the integration in HA is piece of cake. 
hi is there still someone working on this?? I got the wifi module, but don’t have the knowledge
If you would have the tools to look into the serial connection between the Wifi module and the controller, that would help us out a lot
what tool I need to that?? another thing would it be possible somehow hack the API form the myfire app ??
I also have the WiFi module. I asked Mertik about the protocol, but they referred my to the producer of the fireplace?! The I reverseved engineered the android app, but I could see how the actual communication is done.
(https://apkpure.com/myfire/com.iqontrol.mertik)
Any ideas on how to approach this?
Will the WiFi module offer more functionality or performance to HA than the radio version does?
May be this link helps some of you getting rfxtrx working on ghe Mertik Fireplace:
This is an old thread but I found it as I was researching automating my fireplace. I don’t have a Mertik but I have a Valor which appears to use the same Wifi module as Mertik.
I’ve been meaning to attempt to reverse engineer the protocol used for the Wifi app but haven’t been able to spend the time yet. I was able to get a network capture on from my phone while I was using the app. I wasn’t able to easily and quickly decipher the data so I put the project on hold.
Since then I’ve learned a little more. My guess (haven’t verified this yet) is that the app simply sends the same commands as the RF remote but wrapped in TCP. I’d have to do another capture and verify this assumption but if it’s true it should be pretty easy to code something up.
I’ll get around to doing this sometime but if anyone is still interested in working on this and gets to it before I do I could share a network capture.
Hello,
For what it’s worth, I too am about to try to do this with a valor fireplace so any updates or findings in getting this to work would be awesome! My initial approach was going to be to try to capture the codes using an ardunio and a receiver and try to use esphome to build a second remote, but I also admittedly don’t really know what I’m doing…
While searching to see if there was an HA integration I happened across this thread but also this GitHub repo which seems to have done at least something toward getting a working solution with the WiFi module with Homey.
Not much more to add than that unfortunately. Maybe the above helps someone to put something together for the WiFi module.
Did anyone came up with working solution ? My idea was to replace this wifi module of mertik maxitrol with esp32.
I got the source code from apkpure.When i try to run the app in Android studio, it always shows error in String str = BuildConfig.FLAVOR;
^
symbol: variable FLAVOR
location: class BuildConfig
if anyone has any guide in replacing this wifi module, please write. 
I have been struggling with this for two weeks, and i have to complete this task. 
Did you find anything? i have the protocol.
I have not worked on this topic since my last post. But with the informtion from the project Lewis linked to, I believe I can convert it to a HA integration component. Give me some days, and I examine if the connection is successful
I also did exactly as you did. converted apk to source code. But there is always this bulid.config error.
I have the esp board, i have to replace the wifimodule of mertik maxitrol to esp. I have the protocol. But i dont know how to do this task.
This app is only connected to the wifi box of maxitrol and not to esp(because of the protocol). Or how do i program this esp that it is getting connected to app and control the fireplace. Really need help. IT HAS BEEN THREE WEEKS WITH THIS STUFF 