Ok so I need some help to debug a possible issue , I believe it something to do with the mains wiring setup for my HestiaPi’s to boiler connection.
I had a previous issue with the raspberry pi’s being killed off after a few days of switching the HestiaPi’s On, however this was some time ago and seemed to be sorted by the updated PCB.
However I still notice that if I turn off the downstairs HestiaPi and then immediately turn off the upstairs HestiaPi it would send a sort of shock through the screen but this would disappear a few seconds later and no dead Pi’s , I discovered that if I waited a few minutes between switching each HestiaPi off this fault didn’t occur however 2 days ago I implemented the Auto schedule on IOThermostat image and and of course set the times on both thermostats the same to come on .
Then yesterday the HestaiPi upstairs just had a black screen and no lights on the Pi not long after turning the heating on , a quick reboot and everything seems normal. this made me think that maybe its the same fault that both HestiaPi’s turning on and off at the same time caused a fault and crashed the Pi , but no dead Pi which is always good .
I’ve since change the times so that they are 10 mins apart between both HestaiPi’s turning on , and good news it seems to be ok . Nothing shows in the log which makes me think its something to do with the way my wiring is set up .
Nov 17 04:52:30 iothermostat mosquitto: 1542430350: Saving in-memory database to /var/lib/mosquitto/mosquitto.db. Nov 17 05:52:31 iothermostat mosquitto: 1542433951: Saving in-memory database to /var/lib/mosquitto/mosquitto.db. Nov 17 06:52:32 iothermostat mosquitto: 1542437552: Saving in-memory database to /var/lib/mosquitto/mosquitto.db. Nov 17 07:00:02 iothermostat python: IOThermostat: GPIO.output(23,1) Nov 17 07:52:33 iothermostat mosquitto: 1542441153: Saving in-memory database to /var/lib/mosquitto/mosquitto.db. -- Reboot -- Nov 17 20:24:20 iothermostat systemd-timesyncd: Synchronized to time server 184.108.40.206:123 (2.arch.pool.ntp.org). Nov 17 20:24:20 iothermostat systemd: Started Verify integrity of password and group files.
Ok so how its wired in my house is that the boiler has power to it , a live, neutral and switch live comes from the boiler to both thermostats, the downstairs thermostat is also connected to a pump for the underfloor heating this connection is made in a junction box in the loft where the boiler is located . However both thermostats are connected to the same live neutral and switch live so that as long as one of them is on, the boiler will remain on/ heating the system. The only real difference is that the wiring is shorter on the upstairs thermostat that to the down stairs thermostat and its the upstairs one that always has had problems.
Is it possible that the long wiring to the downstairs thermostat holds some capacitance and if the upstairs thermostat is turned off at the same time or just slightly after it balances back through the upstairs HestiaPi?
I’m only guessing here I just cant work out why its only this one that has the problem and its a completely new thermostat from the one that died originally .
sorry for my very crude drawing .
any thoughts ?