Great project Robi, I look into this every year trying to find a good solution.
At the moment I’m using the ‘ramp thermostat’ in node red which isn’t bad but I miss the manual control and I’m always looking for a better solution.
For sensing, I gave up on battery sensors because of the delay in sensing.
I use esphome in 1-wire mode to support two DS18B20:
To try and get a more accurate and responsive reading, I have the two DS18B20’s in the same room, one placed higher than normal and one placed lower near the floor. This seems to overcome the problems of the room feeling cold before the heating comes on and prevents the room from over shooting the set target temperature to much.
HA then calculates the average of these before feeding node red.
I’m going to download your setup because I like the manual control and see how things go.
I only have the one zone central heating with panel radiators. The floors are laminate, so can feel cold.
I have a esp32 with 1 pair of CAT6 wires and the two DS18B20’s in parallel along the wire. The DS18B20’s are just held to the wall via the cable and a bit of blutack so I can adjust for the optimum position.
Each sensor feeds into Grafana so I can monitor the difference as the room heats up and cools down.
Once I get it how I like it, I’ll mount the sensors in a small sensor housing and wire in permanently.
This was the output from the sensors over the last 24 hours:
They run mostly in parrallel… What’s the benefit? If you have an average of the two, it’s likely like having one sensor located around the middle in between.
You are probable right and this may end up as one for the bin afterwards. As I said, it’s a ‘work in progress’ and Im trying to eliminate the overshot which comes from the residual heat in the radiators after the heating turns off and then having to wait a long time before the heating comes back on again.
3/ The parameters that can be configured with zigbee2mqtt
Min rep interval
5 (s)
Max rep interval
1800 (s)
Min rep change
50 (0,5C)
I think by having any smart setup , it can be used for room’s temperature control eg. with radiator valve like the good old MAX!
I have now a setup of reporting every 0,05C change. It’s quite good , but can be even better eg. report not only by 0,05 C change but every 30 secs instead of only 30 mins
4/ Battery vs. precision
Surely by increasing the reporting interval the battery drains faster.
Actually the CR2450 is about 550-650 mAh, however with a little hack (3d printed case expansion of the backside) 2xAA can be used to increase the lifetime without expecting frequent battery replacement (~ 2500mAh)
5/ Some weird behavior
Few sensors (5 out of 10) were fluctuated initially the measured temperature see picture:
That was observed for few days then I have remove from the zigbee network. few days later repaired them back to the zigbee and I was surprised the problem has disappeared.
All are still fine after one week like the good ones since the beginning…
It’s hard to explain the reason of that situation, probably the sensor inside required a bit more time to be stable after the package is arrived. eg. a kind of humidity issue inside the case…
So finally I am happy so far with that cheap sensor especially because the reporting parameter can be adjusted according to the actual requirements.
Well, I am just testing a kind of “network enabled gateways” like a pure CC2531 used as zigbee coordinator with zigbee2mqtt and a nanoCUL with homegear used for MAX gateway. Both are plugged in into a linux PC acting as network enabled gw. An other linux are accessing both over the network by using usbip feature:
Hi
thanks for providing the solution for controlling the heating, it works perfectly for me, however it hasnt quite got the Wife approval factor. She would still like a manual solution. I dont think she would need a seperate control unit to set timers and temperature, but this would be a solution, I was thinking more of just a physical button to toggle the override input boolean. I have tried to get Alexa to trigger the override, but it doesnt appear to work. Any ideas?
Thanks
Si
Im Viktor from HU, thanks a lot for sharing this, i just started using your 2-zone config and HA for 2weeks, i defo loving it. I just have basic linux and programming undertanding level, but succesfully adapted your project to mine -still in prgress-. Here is a modified look i have done:
My questions:
I have a template warning comes with the new HA version at “as_timestamp” lines, and try to get rid of it by adding “,0” as default, but it not seems ok:
/config/zz_automations/overrider.yaml:
datetime: “{{ (as_timestamp(now(),0) + 7200 | float) | timestamp_custom(’%Y-%m-%d %H:%M:%S’) > 1800 }}”
Another topic is, i would like to have 8minute delay on pump_start at every state change of outputs. (i have wax actuators and they are slow to on -3minutes-, even slower to off -8minutes-) cos the pump flow can be blocked if 1wax is opening and 1 is still closing. I have tried, its working, but not stable…:
# - id: heating_pump_start
# alias: 'Heating Pump Start'
# trigger:
# - platform: state
# entity_id: switch.nappali_perem
# from: 'off'
# to: 'on'
# - platform: state
# entity_id: switch.nappali_belso
# from: 'off'
# to: 'on'
# - platform: state
# entity_id: switch.eloszoba_furdo
# from: 'off'
# to: 'on'
# - platform: state
# entity_id: switch.halo_belso
# from: 'off'
# to: 'on'
# - platform: state
# entity_id: switch.halo_perem
# from: 'off'
# to: 'on'
# condition:
# condition: or
# conditions:
# - condition: state
# entity_id: switch.nappali_perem
# state: 'on'
# - condition: state
# entity_id: switch.nappali_belso
# state: 'on'
# - condition: state
# entity_id: switch.eloszoba_furdo
# state: 'on'
# - condition: state
# entity_id: switch.halo_belso
# state: 'on'
# - condition: state
# entity_id: switch.halo_perem
# state: 'on'
# action:
# - service: timer.start
# entity_id: timer.timer_pump
# - service: switch.turn_off
# entity_id: switch.main_pump
# - alias: delay pump start til actuator opens (timer parameter in main configuration file)
# trigger:
# - platform: event
# event_type: timer.finished
# event_data:
# entity_id: timer.timer_pump
# action:
# service: switch.turn_on
# entity_id: switch.main_pump
Thanks for the answer!
The cycle time is ok for switching beetwen actuators -understand now,thx- if at least one is in open state.
But if all the actuators are closed and heating turns on, the pump switched immediately on, but the actuator still under opening progress.
EDIT: ok…just figured out that i need to invert rpi gpios and rewire to NO relay pin,
to make the actuators normally open by default, so if pump start all open and some
may closing. BUT, i would like to make the system working as well throgh manual thermostat if something fails, or no power on relays. It needs NO actuators that i have and a series thermostat on pump. But i cant handle this no. I need some coding to make all actuators open if pump stopped.
So to achieve the desired working i think:
I have to connect actuators to NO relay pins (and cos they are NO to be able to use them opened by default and without powered HA.
The pump switching circuit can be NC to be able to control overheating and underheating without powered HA and a series thermostat.
Now connected like:
##### Raspberry PI with relay hat
- platform: rpi_gpio
ports:
5: nappali_perem
6: nappali_belso
13: eloszoba_furdo
16: halo_belso
19: halo_perem
# 20: heater_1
# 21: heater_2
invert_logic: False
*It needs to be True and rewire relay*
- platform: rpi_gpio
ports:
# 20: heater_1
# 21: heater_2
26: main_pump
invert_logic: True
*It needs to be False and invert wire relay*
I use actuators which Normal Open by hardware, ie. they need to be applied power to close…
What kind of pump do you use? Modern pumps (like Grundfos) have an adaptive load control mechanism built-in so a few minutes with closed valves should not cause a problem. The pump will self-control the pressure it generates so overpressure won’t happen. As the valves open gradually, pump speed will automatically increase, and vice-versa. That’s a feature built-in the pump, you don’t have to control that.
Yepp, mines are NO as well. Yes there are adaptive pumps on the market, but i found it too noisy (pwm modulation freaks me out), and changed back to normal. …maybe it was a cheap one.
For now i have figured out how to manage the situation to fulfill my fail-safe setup and my needs.
(requirement: pump via NC relay contacts, actuators via NO relay contacts; so if the HA is powered off, because of malfunction, i can adjust max. temp via series manual thermostat)
I have to use +1 relay (i have an 8ch relay board so i can) to cut off the main power from actuators if pump not running, with this, i can cut off all and not heat the actuators if not needed, and when pump start, they are start all open… I tried but i cannot manage that on easier way, will make a drawing, i think it can be a full failsafe system.
