thanks

I've ordered some 3.3V version Arduino Pro Minis and will try again

Ive sorted it

put it next to the pi and it worked then realised I had not put a cap in the PI's radio did that and its now working fine

only had 10 micro_F but seems to be working ok

end Battery Level
3838 TSF:MSG:SEND,254-254-0-0,s=255,c=3,t=0,pt=1,l=1,sg=0,ft=0,st=OK:6
Request Time
4349 TSF:MSG:SEND,254-254-0-0,s=255,c=3,t=1,pt=0,l=0,sg=0,ft=0,st=OK:
4365 TSF:MSG:READ,0-0-254,s=255,c=3,t=1,pt=0,l=10,sg=0:1557689248
Time value received: 1557689248
Temperature is: 2
4859 TSF:MSG:SEND,254-254-0-0,s=7,c=1,t=0,pt=4,l=4,sg=0,ft=0,st=OK:2
Rain amount is: 6
4868 TSF:MSG:SEND,254-254-0-0,s=11,c=1,t=6,pt=4,l=4,sg=0,ft=0,st=OK:6
Rain rate is: 0
4879 TSF:MSG:SEND,254-254-0-0,s=11,c=1,t=7,pt=7,l=5,sg=0,ft=0,st=OK:0.0
4887 TSF:MSG:SEND,254-254-0-0,s=255,c=3,t=0,pt=1,l=1,sg=0,ft=0,st=OK:6

Ok bit of background I have solar at home and have built a power wall . Still have excess 9 months of the year so want to heat some water for free, only snag have a combi boiler

Discovered mine will accept main water temp upto 60 Deg so thinking add a hot water tank before the boiler use less gas.

Only problem I want to ensure that the temp in the tank reaches 60 Deg at least 30 mins each day to limit bacteria

My solar system has mqtt do turning the heater on and off shouldn't be to hard.

Any recommendations for measuring the water temp ?

need to do it with a few live sensors then will be happy

but going to call that a win for today

thanks for the swift replay

thanks all the design has changed I plan to heat some medium and have the water pass though a head exchanger what way standing water will never be consumed later

there is a commercial product called sunamp which is designed for this purpose

Thanks I found the old posts will look for another use for them

Original plan was waking up esp8266s