Is there a sensor available in the integration that reflects the level of demand the heathub requires of the boiler? Maybe sensor.wiser_lts_heating_demand_channel_1 ? I cannot see sufficient history of this sensor in my system to work out what it does.
For various reasons my heathub is not directly connected to my boiler, and I’d like to work out the approximate demand the system expects from the boiler so that I can combine this with the demand from another system (FHEM/FHT) and drive the total demand to the boiler through a custom OpenTherm controller.
I’m fairly sure that the Wiser system is a simple on or off signal to the boiler based on a combination of time of day and detected temperature. So the hub is only really able to say when it has turned on the boiler for either heating or hot water.
That is what my LTS sensor histories show, and not particularly interesting at this time of year when the heating isn’t needed.
My boiler isn’t OpenTherm capable so there may be other data for people who have that - but if your boiler isn’t communicating directly with the hub I doubt you would see different.
The sensor.wiser_lts_heating_demand_channel_1 sensor does show the boiler demand (if you have a hot water and 2 channel hub, you will also have a channel 2 sensor). However, as @dunxd said, this is then translated into an on/off state of the relay for the boiler to fire. Not sure what % it has to hit to turn on the boiler and think this is some calculation of the individual TRV demand %s. If you have connected on opentherm, you would get other opentherm sensors that show the boiler demand more reflective of what is actually happening. You can also look at the wiser heating sensor to see a history of the boiler actually being fired or not.
In an OpenTherm system the hub (or equivalent) should change the boiler flow temperature setpoint in accordance with some calculation of how much heat the system requires - e.g. average iTRV actuator setting. This is what I mean by ‘demand’. In a relay switched system a similar demand effect is achieved by a PCM on/off control of the boiler, with the flow temp set manually or maybe by weather compensation in the boiler. This is why OpenTherm + well behaved modulating boiler should offer greater efficiencies as the boiler can operate for long periods at low power levels in the fully condensing state. Unfortunately my OpenTherm boiler is not so well behaved so I use a bespoke control algorithm to tame it a bit, and why a direct OT connection from the heathub wouldn’t work for me.
I’ll experiment with the system a bit without the boiler connected / running and I should at least see how the demand sensor varies and work out what to do from there. My control algorithm runs in Node-RED so will be relatively straightforward to amend.
I would add that the hub does provide data for opentherm but we dont create a sensor for it unless we detect it is connected. If you look at the diagnostics download data, you will see the opentherm data. Im not sure if it does update if not connected but you could download it a few times with some testing and see if it does. We could then include a config option for you to create the opentherm sensors if not connected to use in your nodered script.
I’ve had a quick look at it this afternoon. The 'sensor.wiser_heating.percentage_demand_Channel-1’ seems to be what I’m looking for, so no change to the integration required.
The ch1FlowSetpoint in the diagnostics just seems to switch from the lower value (e.g. 350) to the upper value (e.g. 800). It may well be more useful when OT is connected. If I have time I’ll try temporarily connecting the hub to the boiler and see what changes.
There is definitely some form of integration factor in the hub’s control algorithm as the demand value increased over time with a simple half degree temp +ve demand set on a couple of rooms which went unsatisfied.
I’ve set up some better logging to influx and have a play over the next week or so to see if I can determine the characteristics of the demand signal and the maybe the control algorithm used.
Thanks so much for the discussion on the way that the hub communicates with the boiler. I had assumed that it was a simple off/on, and hadn’t noticed that the Heating Demand Channel 1 LTS was a percentage - during the summer months there has been no demand at all recorded, but if I go back a few months I can see a couple of spikes around 40%.
My boiler is a system boiler with separate hot water tank and doesn’t support OpenTherm, so I am assuming for me the hub just uses the demand value to decide whether to turn the boiler on for heating channel (or if it just turns it on any time that any of my thermostats detect a room is below the setpoint.
For combi-boilers with OpenTherm it would be interesting to know if the hub sends the boiler more than off/on commands.
Yes for opentherm it tells the boiler what temp to heat the water to. See above post with the opentherm output from the hub and you will see the ch1FlowSetpoint value for heating channel 1. I have no idea how much cost saving this generates and how often it heats less than the max 80C in real life as mine is also non opentherm.
My understanding is that, in a modern condensing boiler, as far as efficiency goes it’s the return temperature that determines the marginal boiler efficiency. To ensure ‘full condensing’ the flue gas needs to cool down below ~ 55 deg C whilst still in the heat exchanger. Modulating burner controllers (i.e. the controller that’s part of the boiler) should reduce their heat output to maintain the set flow temperature. Given that most radiators (when practically sized) will only develop a temp drop of 20 deg C when room temps are much lower than desirable, its easy to see that an 80 deg setpoint is almost certain to a) push too much heat into the property and b) almost ensure the boiler isn’t operating at max efficiency.
If you don’t have a room or weather compensating controller of some form setting the boiler flow temp, you must ensure that you manually adjust the flow temp to match the season. Even in the coldest months of the year we’re unlikely to want 80 deg C flow in the steady state (all rooms at temp) as most boilers are well oversized for steady state demand. However, we also demand rapid heat up in the morning so end up with a compromise setting.
BTW - as a test I connected the HubR to the boiler using OT today. It works (the boiler responds to the HubR), but the HubR hasn’t activated OpenTherm modulation -its still working in On/Off mode Diagnostics say
“ModulationOnboarding”: true
so the Hub seems to know that it can use modulating control. Maybe it takes a little time to activate, anyway I’ve raised a support request with Schneider and we’ll see what they say.
Sorry if this has already been covered in the past but i tried searching, does the integration support the Wiser PowerTag and/or Energy meter Gateway from Schneider?
Looking at the documentation/github page it dousent but wanted to make sure as its part of the wiser branding.
Heard back from Wiser this morning about why the HubR was operating my OT system boiler in on/off mode. Their response is:
At the moment our Opentherm is only compatible with our WISER Kit 1 and combi boilers. It’s not compatible as yet with any of our other kits or boiler types.
This is something we are working on with OT to get a resolution.
For maximum usage of your system right now, it’d be advisable to disconnect the OT module and run the boiler from relay mode.
I have to say that it doesn’t seem obvious from any of their documentation that they don’t support system boilers with OT modulation. Glad I have my bespoke OT/MQTT adaptor (ESP + Ihor Melnyk adaptor + custom code driving MQTT messaging) + Node-RED boiler controller algorithm.
Good evening all - Thank you @Angelo_Santagata for the excellent work first of all!
I’ve been collecting info and setting up some basic cards for my setup, but I’m failing at some fairly basic steps. Sorry if this has been covered before, I wasn’t able to find it.
This is what I am trying to make - fairly simple I think?
This is the code I currently have (nevermind the cancel button code, it’s just copy+paste from the heating card)
What I don’t understand is where to ‘direct’ the service call to. Because as it is, HA complains the service can’t be called without an ‘entity_id’ or ‘device_id’. I tried with button.wiser_boost_hot_water but it’s not working…
I worked it out on the heating card, I used the thermostat (not actually tested yet). But this one doesn’t make sense to use the same device?
Can anyone help? Seems fairly straight forward to me, yet I can’t work it out?
Have to try this, but before I do that (and stop working) Mark Parker @msp1974 deserves much more thanks than me. Since my new kids born hes been doing by far the lion share of work…
I should add that looking more closely at this now, this makes no real sense! It was there before we added the buttons and never thought to make it more obvious with this new functionality.
I will open an issue to remind me to review this and likely make the boost button entity also a viable entity option.
Firstly, I want to thank the the hard-working people behind the repository. I first saw this repository a few years ago, and it is literally because of your work that I chose a Wiser system. I’ve had the Wiser system for a few years and am very happy indeed. I had messed around with home assistant before with X10 devices, and now have integrated Wiser properly. The repo is amazing. Respect!
I have a Q. Can a non-Wiser thermostat be used to trigger a zone/fire the boiler? Is there an entity for the zones?
I saw that the Hub device has two sensors for “Wiser Heating” which must be our two heating zones. But I can’t see somewhere to activate those zones. It seems that only Wiser Rooms can call for boiler heat, via a TRV/Roomstat in that Wiser Room.
I ask because we have a Kitchen kickspace heater. The official Wiser electric heater switch wasn’t usable, because it could not call for boiler heat (was expensive). It assumed it was controlling an entirely electric heater. Our water heated kickspace heater only uses the electricity for the kickspace fan. So have installed an Athos Tasmota switch via MQTT to control the fan.
The problem is still then how to call for boiler heat without heating other rooms that have Wiser TRVs. We could put in a Wiser Room Thermostat in the kitchen, but they are silly expensive. Would be great to use a basic thermostat of some kind in Haas.
Many thanks in advance for any ideas or observations.
In general our integration can only perform the same functions as the wiser app, albeit, our integration allows additional logic/automation to those functions. I dont have a 2 zone hub but if you can activate the zone in the app we should be able to add that to the integration.
The general way the wiser system works is that it relys on some temp sensor linked to the hub zigbee network to drive the demand (and it will only pair with wiser devixes) and as such, the wiser way to do this would be to add a roomstat to your kitchen to fire the boiler and drive your kickspace heater. In theory, you could also use a trv on the heater pipework with a little hacking which would also stop it unnecessarily heating the kitchen if the boiler is firing for another room, however the temp sensing could be inaccurate.
Anyone else chip in if you have ideas to help @rr4444.
