Hot Tub Temperature Probe

[DavidK]

Jerry
Your are correct, we don’t need any deteriorating copper. I will think about cutting the insulation away from the fiberglass to paste my sensor. But first I found a plastic hot tub thermowell on EBAY for less that $5. It screws right into a PVC fitting. Just the ticket!! Will give that a try first.

Built up a simple 433 MHz radio link using a 12F683 (TX) & 16F876 (RX), then tested it all weekend. Transmitted simple ASCII code every second at 2400 baud and checked for clear data; 10 errors in a little over 30 hours, that is better than 99% reliability. I can live with that. Coding up the DS1820 is next.

In my junk box I have some low voltage contactors that would work for running the pump, and heater. Your suggestion to review the Parallax Industrial Manual was great. It has some good stuff in it and it will give me a good start if I decide to replace the tub controller. Just might do it anyway just to prove it can be done. Thanks for the tip.
David

[precision]

I always makes to put a DS1820 series inside a 6” of ¼ copper tube. 1mm of ds1820 will remain out from tube to other end, After i seald with Mseal or M-Seal Easimix - 20 Epoxy Putty.( That uneffected withstands temperature up to 180°C ) and avilable in only in 0.37$ in india into tube formate.
one tube is sufficient for about 50 nos. 1820 sensors.
see property of epoxy putty http://www.pidilite.com/productinner...65&subcat2=184

[DavidK]

precision
A quick Google search and there does not appear to be a US distributer for M Seal. However, I did find “Mighty Putty” and “Plumbers Putty.” Maybe they are the same thing as M Seal.

Because of the chemicals in the tub I would probably try plastic first not copper and let it set in the water a week or so to check for leaks. Thanks for the suggestion.