May 20, 20233 yr Intermittent temperature reading issues below a certain temp; i know theres some very clever okes here might know what causes this 😉 Connected a Sonoff TH20 Elite temperature sensor to my geyser. This uses 1-wire comms between probe and Sonoff device. Direct connection all works well (30cm probe wire length). I then extended the probe cable using UTP CAT6 cable, roughly 5m length. Comms and ground to one twisted pair (orange & orange/white), and power to a single strand of another twisted pair. (Green). "Extended" using two sets of CAT6 crimps and extender adapters. Important: the one extender adapter sits in a "housing" on the side of the geyser which gets pretty warm...  ISSUE: intermittent temperature readings! As soon as the geyser temp drops below roughly 43deg, the temperature is no longer shown, until heated up beyond roughly 43deg again (between 42.5 and 43.3 seems to be the "cut-off" point). What the heck could be causing this???? I've done some basic troubleshooting, with more troubleshooting ideas, but access to the geyser is a mission hence hoping someone has an idea off-hand how to resolve this... Troubleshooting thus far: 1. Originally the individual probe and UTP cables were just twisted together with some heatshrink (inside the warm box on side of geyser). Replaced this with UTP connectors and extender adapter. Problem persists. 2. Ran a separate temporary 5m UTP cable extension, away from all potential electromagnetic interference, problem persists. 3. Got another temp probe, crimped with UTP, and connected directly to the "close to sensor" UTP extender (i.e. roughly 30cm between sensor and probe, with UTP extender in between but no UTP cable). Tested with a mug of luke-warm water and waited for temps to drop - worked perfectly all the way through 43deg down to ambient. 3. Connected same new probe at the geyser UTP extender. Funny thing, outside the geyser box it read the value (ambient about 20deg). I then placed this replacement probe (and UTP extender) inside the geyser box to let it run for a while and see performance over time. HomeAssistant shows very quick temp rise and within around 10secs, passing 30deg or so, readings stopped (by which time I'd already climbed down the ladder 😉 Water temp at the time was below the magic 43deg, as soon as I heated the water beyond 43deg this "replacement" probe started showing the temp again. i.e. Problem persists, it's not a probe issue...  Further troubleshooting ideas (very much open to further suggestions here): 1. Place the UTP connector (extender) outside the geyser box. As mentioned, it gets quite warm in there, BUT the connector seems to happily work when warm above 43deg, which is counter-intuitive. (But seemingly also happy below roughly 30deg). This connection having previously been "hotwired" together though I don't think the problem lies here...Anyways, ill temporarily route the probe cable and extender outside the box and see what results this gets. 2. Would changing the UTP to STP (shielded cable) help? I suspect that won't make a difference, but worth a troubleshooting attempt? 3. Actually spend some time up by geyser (yay!) with lukewarm cup of water, running sensor from around 50deg down to ambient...alternating UTP connector inside and outside the geyser box, alternating between the two probes. For sure I'll get some answers from this experiment, but I'm trying to avoid having to spend extended periods of time up there, or having to go up at all, 😆  Any ideas / thoughts?
June 21, 20233 yr @markus_m2Â did you ever solve this? I have exactly the same issue. Outside of the geyser it works perfectly even up to 75 degrees, however the moment I put it into the geyser probe port. within 30 seconds it fails.
June 21, 20233 yr I thought it might be some short circuit against the element, but I wrapped the entire unit in tape and no change. this is so frustrating as I've redone the wiring several times and checked solder joints as I'd soldered mine...all is perfect. Pull it out of the geyser and its starts working Â
June 21, 20233 yr Author Hi @brussel, I meant to update this thread but clearly forgot... Replaced the cable with SHIELDED UTP5, works perfectly! Been going over three weeks now, 30deg up to 65deg, reads perfectly over the shielded cable...
June 23, 20233 yr many thanks. I eventually moved the device and shortened my cable to under 2m and voila no issues. It definitely is n issue with extending the cable. the documentation says you can do 60m. not quite!
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