Ground Heater to Picaxe control

newplumber

Senior Member
Hi picaxe friends

I have been working on rebuilding one of our ground heaters control panel for some time
because the OEM used mechrelays which were corroded + one board was fried.
So I decided to try give it the "WORKS" or for me "STATE OF THE ART"
My control board gives me alot of information and uses 3 P20x2 chips.
(which 20x2 is new to me but love them and love the memory for my unprofessional code)

The control board has\/

5 ds18b20 temperature sensors
1st- for the main/supply glycol temp (St top LCD)
2nd- for the return glycol (Rt top LCD)
3rd- for the overheat (OHT middle LCD)
4th- for dieselfuel heat exchange (FX bottom LCD)
5th- for the dieseltank (Tkt bottom LCD)

1- glycol flow meter..has to be cali still (Pflow middle LCD)

2 Current transformers
1st- reading pump amps (P=#.#A middle LCD)
2nd- reading Burner amps (B/Amp#.# bottom LCD)

1- glycol tank float switch (no visual)

2 pressure transducers
1st - reading glycol pump pressure (PmP middle LCD)
2nd - reading how much fuel in the diesel tank (FTL= bottom LCD)

1- potentiometer for setting custom temp (TEMPset= top LCD)

3- solid state relays
1st- preheater goes high if temp=< -0 f for 5 min
2nd- glycol pump
3rd- diesel burner/boiler

1-aquastat for the burner (just incase my digital friends fail)

500+/- hours reading picaxe forums/200 hrs processing some big words

End results = I was very excited to see it all work in place after
many hours testing on breadboards. After I had my control board finished (not installed then)
I placed it in the freezer for 30 minutes then took it out and powered it up with
surprising results....it all still worked!! I also searched diesel weight/height and calulated
my diesel tanks for how many gallons using the 0-5 psi pressure transducer and the bottom LCD
switches back/forth from ftl= ... to height of fuel from bottom of tank and when I fired up the control
board it showed 28" from the bottom which after i physically meassured the fuel level it was right on.
Now its easy to fix problems at 60f + but next winter at -20 below will it work? If not I have a few
backup plans ... with OUT the use of a fuse and some big explosion material.
Anyway I would like to say thanks to you all for helping me from different Pforums to make it possible.
I would show a schematic but its in "my" plumbergreek langauge :) but it works and I'm happy.
your almost truly friend
have a good weekend I'll be back some monday
 

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newplumber

Senior Member
Thanks Ibenson but it wouldn't been built if it wasn't for forum helpers like you/all
that was probably my most time eating project but I believe that harder it is the bigger the celebration.
But learning is the best part ( it just takes me 20 times longer)
Now onto project #531 (project #018 thru #530 was projects my breadboards couldn't understand short circuits) jk
 
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