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Author Topic: Hot water cylinder temperature gauge  (Read 5084 times)
Zaph
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« Reply #15 on: August 17, 2017, 08:16:43 PM »

Agree Fionn. 3 is better.
I intend hooking a logger up, and connect it to a tablet computer/browser display. And then have top, middle and bottom, but before all the wiring maze starts to starts, just a single display. The trouble is in summer the topmost temp is most usefull, but in winter, the back boiler feeds in at the top. so the bottom temp is more useful, so all 3 are going to be needed.
Eventually want to try monitor the back boiler inlet, and ensure that my pump does not rush cold water into it. Will probably take me ages, but winter is coming, so I better get cracking.
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10KW back boiler, old house, small scale solar heating. Rudimentary.
mr_magicfingers
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« Reply #16 on: August 17, 2017, 09:39:35 PM »

I'd be interested to know how you get on with the logging, I've not figured out how to do that easily. Having it available via a web interface would be very useful.
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Solar PV: 6kw (24 x REC 250w), Sunny Boy 3600TL-21, roof facing 178 at 40 slope.
300l Thermal Store, 2 x 3kw immersions via Immersun + Dunsley Yorkshire WBS
Woodwarm Double sided 6kw WBS
7 acres of old woodland I'm slowly bringing back into order.
regen
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« Reply #17 on: August 18, 2017, 06:37:24 AM »

As per Mr. Magic fingers

I installed 16 of these 1.00 chinese jobbies over 2 years ago,extending the wires using Cat 5 by as much as 8 metres and simply twisting the ends together. They came with batteries and 15/16 are still working fine although some LEDS are getting a bit DIM. I doubt they are accurate to better than +- 3 degrees. For the tank I just put them into the probe pockets top and middle- actually its a thermal store. They also measure things like all the room temps and IN/OUT temps for the wood burner,oil boiler, under floor heating and rad heating circuits as well as attic temp and TS pipe to tank. Mostly they are taped to pipe under insulation.

After a couple of years most are no longer even looked at but did help when system was first used. However those on the Store are used daily, particularly in summer and if the sun aint shining then the oil boiler can be flicked on manually.

For about 50 in total its been a good investment and no complaints about the Chinese jobbies.

Regen
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3.92w freestanding PV with sb3300 +Imersun
21kw Stratford T70 woodburner
 300litre thermalstore with 3kw and 1kw immersions
 Wall star 25kw oil boiler
  Spring water supply with uv and ro membrane
 Sheep, poly tunnel and approx 80 sq m of raised veg beds.
TheFairway
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« Reply #18 on: August 18, 2017, 11:16:34 AM »

...I doubt they are accurate to better than +- 3 degrees.
Odd as if they are the Maxim single wire probes, they should be accurate to about +/- 0.5C even at the lowest resolution - the sensor supplies the temperature reading so the host just needs to read it. I had 5 in parallel linked to a Arduino test board and they all sat within 1C of each other.

I guess its how they are mounted. My final intention for the 5 above is for the tank (probably supply, bottom, mid, top, draw off) and was thnking of drilling out a hole in the tank insulation, filling with heat sink compound then pushing probe in until it hopefully touches, probe end on with the tank. Wonder how well this may work.

Yes, just checked -
https://datasheets.maximintegrated.com/en/ds/DS18B20.pdf
or
https://datasheets.maximintegrated.com/en/ds/DS18S20.pdf

« Last Edit: August 18, 2017, 11:21:04 AM by TheFairway » Logged
Zaph
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« Reply #19 on: August 18, 2017, 01:24:56 PM »

Yep. A winter project, which will probably only be working in time for winter of 2019.
I'm trying to find the lazy way, because, I have some programming skills, some electronics skills, but not much cash, to buy a Hive, Alexa or a Philips solution. And enjoy building stuff - based on many people on the webs sharing their Raspberry Pi builds, want to copy ideas from the PiMon system, without paying for sensors and boards that I might not need initially. If you browse my website link in profile www.softcircuitry.blogspot.com , you can see I have built basic Arduino setups in the distant past when I had more time. The DIY needs of the new old house have been an immense drain on my hobby time.
I will defo paste some pics once we get some temperature readings, since that will encourage me and others to keep optimising our power consumption. My system still will rely on a 3KW immersion heater, which I hope to relegate to emergency use only. My biggest power use at the moment is running 3 computers, I have 2 teenage computer-gamer pros, so they will be one of the first things to try cut down.


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regen
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« Reply #20 on: August 19, 2017, 06:30:11 AM »

uote from: regen on August 18, 2017, 06:37:24 AM
...I doubt they are accurate to better than +- 3 degrees.
Odd as if they are the Maxim single wire probes, they should be accurate to about +/- 0.5C even at the lowest resolution - the sensor supplies the temperature reading so the host just needs to read it. I had 5 in parallel linked to a Arduino test board and they all sat within 1C of each other.


I suspect my perceived inaccuracies are due moe to differing wire lengths,poor joining connections and differing contact with the pipe under insulation etc rather than inbuilt inaccuracies in the units themselves. However exact measurements were not important to me only replication.

Regen
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3.92w freestanding PV with sb3300 +Imersun
21kw Stratford T70 woodburner
 300litre thermalstore with 3kw and 1kw immersions
 Wall star 25kw oil boiler
  Spring water supply with uv and ro membrane
 Sheep, poly tunnel and approx 80 sq m of raised veg beds.
eabadger
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« Reply #21 on: August 19, 2017, 11:25:24 AM »

my chinese ones nearly a year on still working, i use the type with the relay and use this to switch (via a proper relay) different circuits in and out.
i have extended all leads and see no change of accuracy, biggest issue is fitting in the sensor pockets, i pack with fibreglass.
i think mine cost about 3 each but very worthwhile, you could in therory use one display and switch the sensor to view each.
 


* IMG_0469.JPG (547.23 KB, 1632x1224 - viewed 259 times.)
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
biff
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« Reply #22 on: August 19, 2017, 11:49:31 AM »

That is impressive Steve,
                          Biff
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An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
eabadger
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« Reply #23 on: August 19, 2017, 12:03:09 PM »

have tidied up since then, they check gravity flow and return temp then bring on pumps, added a priority switch now so floor or rads get heat first after dhw.
they check floor and rad flow and return temps and dhw cylinder top and bottom.
you can set these sensors to switch on low or high temp, they dont make that clear when selling, but knowing it is a plus point.
all simple to do but does the job well, this is in what will be a cupboard in the dining room, currently we are using as the living room whilst what is to be the livingroom is my workshop, so i can sit and watch the numbers whilst watching telly, a bit addictive, sadly.

steve
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
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