Radian

Only understandable from a financial POV? At worse, provided the ASHP is sized to meet the losses, the COP should fall to no less than three on average throughout the year except possibly for HW usage in which case a COP 1 immersion heater might be taking over with higher running cost compared to combustion heating.

Thanks for that. My knowledge of different boiler types and configurations is definitely behind the electronics side of things. Also, the most sophisticated control system I've ever owned (apart from my own current design) was a battery operated wall thermostat with a weekly timer! If I can get control over flow setpoint I'm on my way to separate HW, weather compensation, and maybe other optimisations I've not thought of?

Sorry about that, but you did. 😁 Clearly this kind of AI is going to be the future of search engines. ChatGPT gained 1 million users in under a week. Here’s why the AI chatbot is primed to disrupt search as we know it. If it all gets too out of hand you could always start another thread in Stoves, Fires & Fireplaces and not mention AI at all.

Absolutely. All these microcontroller systems are alike in many respects. And microcontrollers are at the heart of just about every appliance out there. I've made a living out of designing them into numerous different products and have also cracked open just as many designed by others and you get used to a kind of design style. It's also really useful to be able to bend them to your needs.

I guess this post doesn't really belong in Boilers & Hot Water Tanks so I'll offload it in this subforum. The central heating system in our house is fired by an ageing Glowworm Flexicom 30HX (heat only) condensing boiler. It's probably on its last legs but while it still works I'm keen to squeeze every drop of life out of it. The main drawback with it is that there's only one flow temperature (set on the front panel display with a couple of pushbuttons) for both heating and HW, with only one demand switch input. Because of this limitation I have to set the flow at around 65oC minimum in order to get anything over 55oC into the HWC so I can't have a lower flow temperature separately for the radiators - which would improve efficiency. Not without investing a few hundred quid in Glowworm's own external control kit that is... this kit talks over a proprietary serial bus called "ebus" and combines a switching unit with inputs for HW cylinder stat and room thermostat(s) for CH temperature and scheduling. Luckily for me, Glowworm were gobbled up by Vaillant before the Flexicoms were released, so under the sheet steel it's pretty much a Vaillant ecoTEC with some budget component choices so while Glowworms don't get much attention, plenty of people like to integrate Vaillant boilers with the HomeAssistant OS. For this reason I set about seeing if I could adjust the flow temperature over ebus using the RaspberryPi that already runs my CH system. If I can make it emulate the external controls, I can set a lower flow for radiators and UFH and implement an X plan scheme. The first step was to pick up a spare main PCB and display panel on ebay to mess around with (too cold to risk messing up the real boiler). Here it is dangling precariously on the bench: It's powered from a 240V isolating transformer so not quite as lethal as it looks. Not quite. The first thing I noticed was that, in its former life, it was a combi boiler (Flexicoms come in three flavours: CX (combi) SX (system) or HX(heat only) like mine). For giggles I stuck some 10K resistors on the NTC sensors and water pressure sensor to see how it would run. It still kept throwing faults until I did some googling and found out that the pump is tested on power-up by looking for a small increase in pressure when running. This was fixed by manually tweaking the pot a bit and kept it happy enough for me to play with the serial interface. That's about as far as it will go without an fan and ignition unit though. But at least I could connect it to an ebus interface and talk to it. There are some PCB's out there to interface ebus to RS232 but it's a simple enough thing to design so I built one on some stripboard that plugs onto the Raspberry Pi header: The two wire link is going off to the main boiler PCB (although the wire magically changes from black to white along the way!) If anyone's the slightest bit interested I can put up the circuit diagram for the interface board but it's just a dual comparator and a couple of opto isolators. Incidentally, this interface and topic in general might be of interest to anyone looking to integrate Vaillant boilers with other control systems as they don't talk Opentherm. The awkward thing about this particular hack is that ebus timing can be quite fussy when doing bus arbitration and the UART in the Pi has a fifo that gets in the way. However someone already fixed this with a kernel module called ttyebus dedicated to reading/writing directly to the UART. Then there's the oh-so-handy daemon for linux called ebusd which can interpret a wide variety of ebus device comms and access it all over TCP, HTTP, MQTT etc. On putting all this together, the automatic scan performed by ebusd instantly identified the boiler and loaded the appropriate configuration files for it resulting in access to a great many parameters: bai AccessoriesOne = extheatingpump bai AccessoriesTwo = storagechargingpump bai ACRoomthermostat = off bai averageIgnitiontime = 1.3 bai BlockTimeHcMax = 18 bai BoilerType = 6 bai ChangesDSN = 0 bai CirPump = off bai CounterStartattempts1 = 3 bai CounterStartattempts2 = 0 bai CounterStartAttempts3 = 0 bai CounterStartAttempts4 = 0 bai currenterror = 75;-;-;-;- bai DateTime = nosignal;00:00:00;-.-.-;- bai dcfState = nosignal bai DCFTimeDate = (ERR: invalid position for 3108b509030de500 / 072b080101010150) bai DCRoomthermostat = off bai DeactivationsIFC = 0 bai DeactivationsTemplimiter = 0 bai DeltaFlowReturnMax = 22.69 bai DisplayMode = 2 bai DSN = 8193 bai DSNOffset = 1 bai DSNStart = 8192 bai EBusHeatcontrol = yes bai EbusSourceOn = on bai EbusVoltage = on bai errorhistory = no data stored bai expertlevel_ReturnTemp = -1.81;cutoff bai ExternalFaultmessage = on bai externalFlowTempDesired = 90.00 bai externalHwcSwitch = off bai ExternGasvalve = 240 bai ExtFlowTempDesiredMin = 0.00 bai ExtStorageModulCon = no bai extWP = off bai FanHours = 1250 bai FanMaxSpeedOperation = 5780 bai FanMinSpeedOperation = 1500 bai FanPWMSum = 58260 bai FanPWMTest = - bai FanSpeed = 0 bai FanSpeedOffsetMax = -580 bai FanSpeedOffsetMin = 210 bai FanStarts = 30964 bai Flame = off bai FlameSensingASIC = 709 bai FloorHeatingContact = off bai FlowsetHcMax = 82.00 bai FlowsetHwcMax = 80.00 bai FlowSetPotmeter = 45.00 bai FlowTemp = 25.88;ok bai FlowTempDesired = 45.00 bai FlowTempMax = 116.06 bai Fluegasvalve = off bai FluegasvalveOpen = on bai Gasvalve3UC = off bai Gasvalve = off bai GasvalveASICFeedback = off bai GasvalveUC = off bai GasvalveUCFeedback = off bai HcHours = 901 bai HcPumpMode = permanent bai HcPumpStarts = 29164 bai HcStarts = 4500 bai HcUnderHundredStarts = 0 bai HeatingSwitch = on bai HoursTillService = 3100 bai HwcDemand = no bai HwcHours = 263 bai HwcImpellorSwitch = no bai HwcPostrunTime = 80 bai HwcSetPotmeter = 62.00 bai HwcStarts = 22600 bai HwcSwitch = on bai HwcTemp = 116.06;circuit bai HwcTempDesired = 0.00 bai HwcTempMax = 62.00 bai HwcTypes = 0 bai HwcUnderHundredStarts = 0 bai HwcWaterflow = 0.19 bai HwcWaterflowMax = 11.57 bai Ignitor = no data stored bai InitialisationEEPROM = no bai IonisationVoltageLevel = 72.2 bai maintenancedata_HwcTempMax = 116.06 bai maxIgnitiontime = 2.1 bai minIgnitiontime = 0.2 bai ModulationTempDesired = 33.0 bai OutdoorstempSensor = -60.44;cutoff bai OverflowCounter = yes bai ParamToken = 3 bai PartloadHcKW = 19 bai PartloadHwcKW = 30 bai PartnumberBox = 20 00 46 39 50 bai PositionValveSet = 0 bai PowerValue = 21 0a 50 18 64 1e bai PrAPSCounter = 0 bai PrAPSSum = 0 bai PrEnergyCountHc1 = 3291922 bai PrEnergyCountHc2 = 0 bai PrEnergyCountHc3 = 0 bai PrEnergyCountHwc1 = 994043 bai PrEnergyCountHwc2 = 0 bai PrEnergyCountHwc3 = 0 bai PrEnergySumHc1 = 776243897 bai PrEnergySumHc2 = 0 bai PrEnergySumHc3 = 0 bai PrEnergySumHwc1 = 383284736 bai PrEnergySumHwc2 = 0 bai PrEnergySumHwc3 = 0 bai ProductionByte = no data stored bai PrVortexFlowSensorValue = 0 bai PumpHours = 2157 bai PumpHwcFlowNumber = 0 bai PumpHwcFlowSum = 0 bai RemainingBoilerblocktime = 0 bai ReturnRegulation = off bai ReturnTemp = 25.75;65123;ok bai ReturnTempMax = 0.00 bai SecondPumpMode = 2 bai SerialNumber = 42 30 36 30 33 34 35 33 bai SetFactoryValues = no bai SetMode = auto;69.0;68.0;-;1;0;1;0;0;0 bai SHEMaxDeltaHwcFlow = 27.81 bai SHEMaxFlowTemp = 83.31 bai SolPostHeat = (ERR: invalid position for 3108b509030d7304 / 00) bai Statenumber = 98 bai Status01 = 25.0;25.0;-;-;-;off bai Status02 = disabled;76;38.0;80;62.0 bai Status16 = (ERR: invalid position for 3108b5040116 / 00) bai Status = (ERR: invalid position for 3108b5110103 / 00) bai StatusCirPump = no data stored bai Storageloadpump = 0 bai StorageLoadPumpHours = 630 bai StorageloadPumpStarts = 21447 bai StorageLoadTimeMax = 45 bai StoragereleaseClock = yes bai StorageTemp = -14.94;cutoff bai StorageTempDesired = 62.00 bai StorageTempMax = 0.00 bai TargetFanSpeed = 0 bai TargetFanSpeedOutput = 0 bai TempDiffBlock = 0 bai TempDiffFailure = 0 bai TempGradientFailure = 0 bai Templimiter = off bai TemplimiterWithNTC = yes bai TempMaxDiffExtTFT = 0.00 bai Testbyte = 3 bai TimerInputHc = on bai ValveMode = 0 bai ValveStarts = 12893 bai VolatileLockout = no bai VolatileLockoutIFCGV = no bai VortexFlowSensor = 0 bai WarmstartDemand = no bai WarmstartOffset = 0.00 bai WaterHcFlowMax = 0 bai WaterPressure = 0.974;ok bai WaterpressureBranchControlOff = off bai WaterpressureMeasureCounter = 231 bai WaterpressureVariantSum = 65534 bai WP = off bai WPPostrunTime = 5 bai WPSecondStage = off broadcast datetime = no data stored broadcast error = BAI broadcast hwcStatus = no data stored broadcast id = no data stored broadcast id = no data stored broadcast load = no data stored broadcast outsidetemp = no data stored broadcast signoflife = no data stored broadcast vdatetime = no data stored general valuerange = no data stored memory eeprom = no data stored memory ram = no data stored scan id = no data stored scan.08 = Vaillant;BAI00;0202;8001 scan.08 id = 21;10;31;0010005484;1300;021068;N6 So far, so good. But the fact this PCB was obviously out of a combi was bothering me so I went about finding how to change the ID. This turned out to be a simple matter of searching around for the correct button presses - which kind folk had already posted details of how to do it. Now it has a new personality, the same as my current boiler! Then things get a bit more hazy. Some people were looking at the ebus traffic coming from Vaillant controllers with the objective of emulating them but nobody was doing the same for Glowworm controls. It's an open question whether or not Vaillant controls could be used with Glowworms but I'd be surprised if they could. However, after adding an extra configuration for the Vaillant external controls I seem to be able to affect some of the registers relevant to flow temperature. For example, sending: ebusctl write -c bai SetModeOverride '0;50;70;-;-;1;0;1;-;0;0;0' results in being able to read back the following from the board: ebusctl read -f -c bai FlowTempDesired 50 ebusctl read -f -c bai StorageTempDesired 70 The first parameter for SetModeOverride is listed as 0=auto, 1=off, 2=water but the pump relay actually responds differently 0=off 1=on 2=on so I'm not sure what's going on. The second parameter seems to be all I need to set in order to adjust the flow temperature maximum and also shows up when using the diagnostics menu on the LCD in addition to being read back over ebus. I have no idea of the significance of the third parameter (listed as StorageTempDesired in the configuration file) but it seems only relevant to HW in the combi models. Maybe someone familiar with the Vaillant room controls might shed some light? CXdump.txt

Which is why it's worth hacking it clean out of the cloud! It seems the dude that cracked it spent some considerable time reverse engineering the firmware and setting up the web based flasher for his custom version.

That's worth knowing. I wish there was an Icon that sat on the outside wall so no part of the internal ducting had cold outdoor air inside it. When you look at the thermal image in my post about the shutter you can se the entire length of the duct is a cold bridge into the utility room ceiling. Being outside would mean less fan noise, and on the ground floor would still be accessible for cleaning.

Opposition is understandable as is this particular case for reopening. However, either way, it shouldn't have a bearing on the issues surrounding the future of renewable energy. I wonder how long it will be before the general public start to take notice of the growing capacity for renewables as opinion pieces like these become more visible? I didn't know we had Tory donors on these forums 😁

Just read this comment piece by Zoe Williams, a Guardian columnist. At the end of the article she poses this question: So the question is, how have we allowed a sense of hardship and doom to define our energy debate, when we’re on the brink of an entirely new future? We’re partly suffering from collapsing faith in institutions and government. It’s genuinely hard to imagine constructive, farsighted decisions coming out of an administration whose core priority is stamping out wokery in higher education. Perhaps even suggesting limitless cheap energy sounds woke to Rishi Sunak. Yet the more proximal cause of our malaise is that the advances in renewables aren’t reflected in our energy prices, which are set by the gas price. A UCL report noted that fossil fuels set the electricity price most of the time, at levels that are now much higher than the green sources that constitute at least half of the load: so renewables can get ever cheaper and more efficient, and we won’t feel it in our bills. Energy markets must be broken up into clean power and fossil power. Finally, there is a drumbeat of despair that even when inflation has subsided, even after the war in Ukraine comes to an end, high energy prices are here to stay. Oil and gas companies, bemoaning the windfall taxes and green investments required of them, predict prices that are elevated, if less volatile, for ever. “We need to treat energy as something that is not abundant,” said Anders Opedal, chief executive of Norway’s state oil producer, Equinor, this week. The cynicism is jaw-dropping: the fossil fuel industry situates its problems in the green investments that are, in fact, our only salvation. And Conservative politicians and commentators parrot them, through some combination of lobbying and lack of imagination which would be unedifying to pick apart. We will not grasp the scale and plenty of the green revolution until we treat vested interests who naysay it with the scepticism they deserve: and we need to grasp it, if we’re going to make it happen. I'm looking for balance. Is there any comeback at all that can be justified here or is this the slam dunk it appears to be?

Sure, but the other side of the coin is what happens in the future, if distributed generation gets the rewards it deserves when the serious move towards decentralised generation begins.

Could do with a photo showing the velux in context with the reveal and roof but the rafters must be in the region of 175mm? With only 50mm PIR between rafters (none underneath the plasterboard crossing the rafters?) some of the reveal would seem to be flanked by almost direct contact with outside air (assuming ventilated rafters).

What about using these?

That's true. The link to the Hackaday site nicely covers the adaptation of the sensor to free it from its cloud and send out regular temperature & humidity BLE beacons. On the other hand, grabbing the beacons using an ESP32 and sending the sensor data over MQTT isn't something I've seen published so I cobbled together some code of my own - which is a bit of a problem as it's got hard-coded parameters that would need to be adjusted to suit the local WiFi and MAC address of the beacons. Not a show-stopper I know, but it could have been so much tidier and better written! Also, the other slight embarrassment is that I've never had the time to get the hang of GIT for sharing code. Happy to share the C source though.

FYI Vaillant is well covered by ebusd which is a linux daemon for handling communication with eBUS devices connected to the 2-wire bus system used by Vaillant/Glowworm. It can be set up to talk over MQTT and used for reading/writing pretty much everything.

A whole bunch of these Used to be under a tenner. Maybe they still are on ebay. There's good hack that makes them into BT beacons then you can catch the beacons with something like a Pi or ESP32. I went for the latter. It listens for a bit, identifies the beacons (amazingly good range) and sends the readings out over MQTT. A flow on Node Red listens to the MQTT and sends the data off to a MySQL database.

Not quite. Recall the exponential nature of cooling. Both kitchen and lounge need to be at the same starting temperature WRT outdoor temperature. Notice how your lounge was even hotter to begin with in your first test and the loss you recorded was higher.

Like why the losses from the lounge are significantly more than from the kitchen?

But in the winter there's no sun on those faces? Cloud bounce maybe? I've often thought that EWI clad in vertical solar PV could be a justification for the optimisation of winter generation by offsetting the cost of an alternative type of cladding. But only on SE, S, SW elevations.

This house near us is one storey too high. But pretty close to a cylinder with one domed end.

Hence all the talk about 'boring boxes' 😄 Our house is a 'T' shape with the biggest, two-storey, part being the top of the T and the tail being rooms in roof. Rear Loggia and front porch add to the complicated coastline. Volume to exposed area would quantify the situation but the measurements for our house are additionally complicated by having some rooms in a pitched roof. Insulation standards are also 'all over the place' in the various regions - even from new.

The cold hard reality of the seemingly innocuous 0.3 loss is driven home by how much energy is consumed to make up those losses. I plotted a selection of average daily deltas against the day's gas consumption for the house before and after getting CWI installed at the end of 2022. WIth gas at 11p/kWh some days were costing us £20 during December even with the CWI. Winter 2021 was a lot milder hence the lack of data points at the top end. The deviations from the trend lines reflect the days when DHW was used more or less. At least the CWI shows up a bit.

Looking at last night's figures, @dt 21°C (17°C in, -4°C out) my house was loosing 0.3°C.h-1 Going back to Jan 1st when the outside temperature was pegged at 10°C all night, the loss was 0.05°C.h-1 The delta used when measuring this is massively important as both you and Sir Isaac tells us.

Yes of course. What can I see that's actually plugged in from where I'm sat now I wonder? A Laptop, PC, Computer monitors x 3, Printer, Router, Ethernet switch, NAS, UPS, Amplifier, Mixing desk, Graphic EQ, Laser cutter, Laser extraction fan, Laser cooling unit, 3D printer, Bench PSU x 2, 240VAC isolation transformer, Oscilloscope, Signal generator x 2, Amazon Echo, Desk lights x 4, Raspberry Pi x 2, Soldering Iron x 2, Desoldering station, SMT rework station, Soldering extractor, Microscope, Glue gun, and a whole lot of other stuff not actually plugged in at the moment. Haven't used the glue gun in quite a while though.

There seems to be a very sharp cut-off in condensation part way up the left hand side of the frame. This side seems to butt up directly with an internal wall. I'm wondering what the build-up of this is and if there's a substantial cold bridge here. I forget, do you have an IR camera or thermometer?

Great opportunity to pick up some new knowledge but I completely understand if it's not something you're interested in. For the record, MCB is miniature circuit breaker which you should have in your electrical consumer unit and CT is current transformer which is clamped onto one of the big fat wires that brings the mains into your property.