MikeSharp01

It's on but only a dribble, this is going to bite us all in the bum, another good reason not to expose your bum by pushing your head into the sand.

Sorry just did that and I found a whole slew of senior politicians already there - no room for me.

Yep - that's a worry - think I will find some sand and stick my head in it.

Now I must finish my trustee report - sometimes life interferes and not capacatively.

Bugger me, just looked at the tracks above the board taking SDA and SCL from the RTC to the WEMOS lovely and parallel - so thought nice capacitor there, so bent them apart - see pic, works like a dream - dry joint or interference?

Yes, thanks for the heads up on the boot pins - had the GPIO15 with a pullup for the pulses. That has cured the boot from reset switch but the rtc is still error 4 - bus arbitration fault. (Nothing else on the SDA / SCL pins I can see.)

I have moved on and found an interesting bug. If I run the RTC on a nano it works fine, then I transfer it to the WEMOS, first run is fine but next upload it breaks and I get error 4. So for now I will put the RTC on the back burner and work on getting counts back to the server. See if can remember enough Node Red to get that going with MQTT from the device. Might be fun but no more time today. Chores🤨

Yes I thought of that but if I2C is not working then other things won't work and I need to have it available as I want the block to be universal - I have a few other I2C devices so I need to try them and see if it's the RTC, the library (which may not have been extensively tested on the ESP8266) or my circuit / associated capacitive issues. I have played with MQTT on it and thought I could use it to provide a time to all the subscribers so I still keep time if the internet is down.

Ok so I have been working up a ESP8266 based equivalent of the Steamy counter. Although it broadly works I am having a real struggle getting the RTC to work reliably. Technically I don't need it as the receiver end could do all that, I could use the millis() functions to create quite good timing and I need that anyway to measure the interval and get a rough idea of instantaneous KWh. Could do this better with the 32KHz pulse train from the RTC if it was enabled on the boards I have - same as Steamy's. I have tried a slew of libraries but I still regularly get a bus conflict error on all three of my RTC chips and they all behave perfectly on an Arduino nano. As the RTC is currently managing the sensor timings - I put a DHT22 on the board as well for fun, I guess I need to fish out my logic analyser and look at the timing on the I2C to see whats going on although the scope would show me if the edges are fuzzy / noisy. I decided to echo the flashing LED on my sensor and made a bracket I can just tighten on the meter so nothing is actually fixed to it. So work still in progress I guess.

Very well, just conditioning the photodiode and getting the code working, just can't decide where to split the client / server activities. Might get to share something tomorrow.

Absolutely - just need to work out how to use it in reverse so as to get accuracy both ways. Simple question with a complex answer - did we already discuss this? Why not get another meter and connect it backwards so it flashes on export!

So really the energy monitor using the red light is not going to be universally useful but will work in non export situations or we need to add more features / intelligence to get a more universal solution.

Why would it come on if no chargeable current is flowing surely each complete pulse is 1Wh so turning it on and leaving it on means more than nothing is happening. Unless it comes on at 90% (or some such) of 1Wh expecting it to fill shortly but it does not. So then the falling edge is the full 1Wh and on means almost there - seems daft though.

And presumably the lights on?

We have LPG heating here at Millstone Manor and it has a standing charge - they call it tank rental or some such but same thing in the end.

These threads are getting mixed up. I redid the sums and I think that I would need about 3.7Kw of cooling to achieve that but if I drop the delta and the ACH it obviously comes down dramatically (proportionally). Looking around this unit (https://www.paulheatrecovery.co.uk/wp-content/uploads/2020/07/ComfoPost-CW6-PAUL.pdf) will almost get to the above, assuming the ASHP can cope.

Thanks - that's all interesting but I don't think any of them will fit in our void, I also would need to plumb the condensate out and, because we don't want to bring outside air in, other than via the MVHR, we would need to recirculate which looks like it adds to complexity somewhat! I think I am going to look harder at getting the MVHR boost to deliver a modicum of cooling - if I get ahead of it I feel, just gut feel, we might achieve it so I need to get back to the sums. See this thread:

Good thought - I had expected to be able to control the fan speed continuously (so right down to very slow) but if I only have a few fixed settings it may be more difficult I guess.

Have not ordered the unit yet but thought I would go for a good amount of headroom to keep it quiet.

Is that equation right, do I have the units correct - I guess it must be, its definitely me, but I get an odd outcome: So 451m3 x 4 x 15 x 1.012 x 8 = 219077J = 7.6Js-1 = 7.6W of cooling which sounds all wrong - need to go back the Thermodynamics 101, which I hated I seem to recall, - or maybe that 451 should be in l rather than M3 and/or the SHC should be the capacity of the whole volume - what have I missed? 4 ACH is the boost rate for the whole house which I guess you would not object to if you needed cooling.

Yes, we have passive standard insulation and the PHPP gives us only a few days (2% = 7 days) of overheating but that is obviously based on past temp data (2018 was our last update to the PHPP package) so we are not far from comfortable. Our only heating upstairs was to be a towel rail in the family bathroom and let the slab do the but if we have an FCU post the MVHR unit then we have that option as well.

No Loft! Unit is in GF Utility room but I think I can find space to run 4 x 90 rather than 2 x 70 flexi pipes.

Yes maybe for those three rooms. Good thought!

Maybe you could continuously / occasionally recalibrate if there was a portion of the day / fraction of a second when your CT could measure a known load (all dimensions) and then see if the resistance measured current value had moved.

This is a really hot (pardon the pun) topic today. OK so we are at the install stage of the MVHR suppose I double up the pipe runs to the bedrooms and cool the air at the MVHR I wonder if could get close to replicating a fan coil unit in the same place. Appreciate that this will cost but its a toss up given the infrastructure fan coil units need. At this stage much easier to run ducts than highly insulated water pipes and we are squeezed for space in the ceilings. I dimmly recall you @SteamyTea doing some calcs on airs ability to carry cooling but I cannot find them on BH - probably looking in the wrong place. Did find this link which seems to say that if I can get to 2 ACH then it might be effective: https://www.greenbuildingstore.co.uk/can-an-mvhr-system-be-used-for-cooling/