Questions tagged [thermostat]

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3 answers
67 views

Can a rheostat (as an alternative to a relay) act as the correction unit in a thermostatically controlled electric heater?

I was studying about the various elements present in a thermostatically controlled electric heater control system. While I agree that a relay can be used to correct the output temperature from a ...
1 vote
2 answers
81 views

Identify the temperature sensor on a PCB

I have seven thermostats (for a fan coil central AC system) that unfortunately havd a big problem. When the relays (three big rectangles in black) are closed to turn on the fan they get quite hot. The ...
4 votes
5 answers
397 views

Electric stove place thermostat so far from heater [closed]

I buy electric stove and found that thermostat placement doesn’t make any sense. The thermostat used seem like one in iron, in that case, the iron heater connected directly to thermostat via ceramic ...
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1 vote
0 answers
75 views

What is this electric heater thermostat component for?

I am trying to fix an old electric heater that does not turn on. After opening the casing, I identified the part in the picture to be probably a bimetallic thermostat. When I push the part with red ...
1 vote
1 answer
56 views

I want to trigger buttons on a touch sensitive control panel (not a touchscreen)

I have this cheap hot tub with an electronic controller with touch-sensitive buttons (not resistive since they work with no pressure, only a light touch). The panel is plastic and the buttons are ...
0 votes
2 answers
77 views

PT100 wiring: use different wires joined together and cable length considerations

I am trying to convert a fridge into an incubator for turtle eggs. I would like to make as little modifications to the fridge as possible (i.e: avoid drilling holes through the styrofoam) so that is ...
0 votes
0 answers
59 views

How did I measure AC voltage without a complete circuit?

I have a mystery I'm trying to figure out. (This is going to sound like a DIY home improvement topic, but bear with me, it's electrical.) I recently installed a new smart thermostat. It requires an ...
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-1 votes
1 answer
211 views

How can I choose the values of comparator resistors?

I have a circuit that I use as a thermostat: My comparator is an LM393. I calculated the reference voltage and the R3/R4 ratio using the hysteresis calculation tool on this site: calculator So I ...
0 votes
2 answers
105 views

Identify temperature sensor in thermostat

I somehow managed to damage the temperature sensor in my thermostat while cleaning corroded battery contacts. Apparently the only fix is "buy a new thermostat", though it is a pity to ...
-2 votes
2 answers
146 views

Is it safe to connect Neon indicating lamps with resistors to defrost timer and other fridge components? [closed]

I want to connect some indicative LEDs neon lights pulled from the switches of a multiple ways extension cord to the fridge. Initially the defrost timer, then later all parts and wires individually so ...
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1 vote
2 answers
193 views

Why is there a resistor in this circuit?

Why there is a 220 ohm resistor in this circuit? Can't we just connect the thermistor directly to the base of transistor?
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0 votes
2 answers
100 views

I don’t know what smart thermostat to use with my high voltage [closed]

I think I have 120v but not 100% sure, I don’t know what the wires do. I live in a condo with water cooling/heating furnace. Can someone help explain what the wiring means. Because I do not have a ...
0 votes
1 answer
94 views

Can I get power from my Thermostat's AC relay wires?

I have a 2-wire thermostat that activates my baseboard heater when the 2 wires are shorted. I did an experiment closing those two wires with a relay and got that working well with an ESP32 as the ...
23 votes
10 answers
7k views

Why do consumer ovens use thermostats instead of PID + PWM?

I measured the temp stability of my oven, and it's a really big swing of 10-15c in a saw tooth pattern. Aren't PI(D) controllers with variable output meant to dampen this type of oscillation? I ...
0 votes
1 answer
297 views

Can W1209 be run with 5V DC only

I would like to control a small heat pad using W1209, using a power bank that provides 5V. My circuit is working if I connect step-up voltage controller to the power bank and increase its voltage ...
0 votes
0 answers
37 views

Modified PWM for faster transient response

My heating controller "Thermostat" uses PWM of the water valve to control the heating power to the room. It has a fixed cycle length and varies the proportion of on-time to manage the ...
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2 votes
0 answers
108 views

Unknown symbol in thermostat schematic - two oblique lines inside a circle

Full diagram: What does the circle with two oblique lines inside it represent? It's an Emmeti Termec thermostat
2 votes
0 answers
81 views

Will my 16 gauge wire eventually set my home on fire?

The fan relay draws 6.0A. That is a safe current for 16 gauge wire. The safety fuse is tripped at 15A which is too much 16 gauge wire. References: The below pdf link shows the Installation ...
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1 vote
1 answer
47 views

What's the Common and the NO in this diagram

I think the browns the common wire and the black is the normally open am I correct?
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2 votes
2 answers
174 views

Unconventional TEC peltier use (heating)

I'm going to be breeding reptiles, so I'll need an incubator. I'm currently thinking about using tec coolers as a heater inside an insulated box. The issue I'm thinking I'll have is that with a cheap ...
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1 vote
1 answer
57 views

two independent zones from central heating unit

I have a central heating unit (a pellet stove) for a two floor house. I'd like to control it independently from two thermostats. The stove at the moment is controlled by a single thermostat input and ...
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1 vote
1 answer
419 views

How to connect 15kΩ NTC thermistor sensor to thermostat which requires 10kΩ NTC thermistor

I have a electric floor heating in my house. Old DEVI thermostat broke down few day ago. Problem is that DEVI thermostats are expensive and a little bit dump (not smart). I want to replace thermostat ...
0 votes
2 answers
2k views

Wiring in Thermostat (Rittal 31100) as a 24V Temperature Switch

I want to wire in the following thermostat. https://proax.ca/en/product/205417/RIT3110000 And am having a hard time understanding the wiring diagram I think I get that 5 is L and can be connected to ...
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0 votes
3 answers
635 views

How does the wired Tado smart thermostat operate without a neutral connection?

I’ve been studying the wiring diagrams for the Tado smart thermostat and noticed that it only uses a live ‘common’ and a switched live to operate. Given the smart thermostat has electronics which are, ...
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0 votes
1 answer
53 views

Heating element for Air Conditioner thermostat

I currently have a series of thermostats that are connected to a window air conditioner, one is used to check room temperature the other is to trick the AC to run to a lower temperature by switching ...
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0 votes
1 answer
28 views

Advice on setting up sensor switch

Hi I would like to fit a (motion sensor/IR sensor) sensor switch to a machine in my catering van. The machine is a 12v machine. I would like to start the machine using the sensor switch and would like ...
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0 votes
1 answer
68 views

Are conventional fridge thermostats active or passive?

I am talking about specifically this thermostat used in cooling systems My query to engineers & technicians is that: Can we check the working of above thermostat with only continuity tester and ...
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0 votes
2 answers
445 views

Debugging an old Thermostat: What component is this? (3 pins SMD IC)

My Thermostat stopped working a couple of days ago and I tried to debug it. The first thing I check is if there is any component that gives a strange result with the multimeter and I found these ...
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0 votes
2 answers
68 views

Regulating precision heating

Whats the simplest electr(on)ic(al) method for heating a coil or similar element to a specific temperature? Generating heat is easy; dictating and regulating a specific temperature is the hard part. ...
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1 vote
2 answers
235 views

Need help understanding details of thermostat wiring scheme

I bought this thermostat to control air circulation, that is using it for cooling purpose. So far I managed to make it work, but I do not fully understand the wiring scheme. I would appreciate help to ...
0 votes
1 answer
65 views

Temperature Sensing and board heat

My goal is to have an accurate measurement of the current temperature in my room, which I will use for a thermostat. The problem I have is I bought this breakout board and soldered it to about 5cm ...
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0 votes
1 answer
94 views

Nest thermostats wiring problem 3 storey house (3rd gen, E, analogue one) [closed]

My house has 3 storeys and 3 thermostats. 2nd and 3rd floor have nest e and nest thermostats respectively. The 1st floor has an old analogue one that used to work ok. After the nest upgrade I noticed ...
0 votes
0 answers
167 views

Reed switch passive interupt for garage heater when door is open (using NC switch)?

I'm trying to prevent my garage heater from running while the garage door is open to prevent it from attempting to heat the entire neighborhood if/when the door is accidentally left open. I have a ...
0 votes
2 answers
7k views

Wiring Nest Thermostat E Heatlink in place of original Thermostat

I have a Nest Thermostat E, which requires me to replace my thermostat with the Nest Heatlink. Google provides step by step instructions on how to do this using a series of questions and answers. ...
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0 answers
72 views

meanwell psu inrush current and temperature sensor

I want to use a Meanwell PCB mounted power supply on my next project. https://www.meanwell.com/Upload/PDF/IRM-20/IRM-20-SPEC.PDF The spec sheet says that it has an inrush current of 20A/115VAC (I'm ...
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0 votes
1 answer
105 views

Insert Arduino into Thermostat circuit, but no common

I thought I was all ready to replace a thermostat with an Arduino. I used a multi-meter and bridged some connections to discover the following: 1. bridging 230V (live) with Cool turns on the Aircon ...
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0 votes
0 answers
55 views

4 Wire Thermostat for Two Separate Heaters

Is there any reason why I cannot use a 4 wire thermostat (Honeywell T410B, DPST) to control two separate heaters (they are fairly close to each other)? The contacts are each(?) rated for 22 A and let'...
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0 votes
1 answer
361 views

Can I simply add a 240V Neutral to SONOFF TH10 when replacing wall thermostat

So, I have purchased a SONOFF TH10 wanting to use it to replace my wall mounted thermostat. The thermostat has 2 connections: Always-Live and Switched-Live (which is activated of course by the ...
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2 votes
1 answer
830 views

What kind of relay should be used to control a thermostat terminal?

I'm building a remote controller for my thermostat, and the only step I have remaining is the connection between the Raspberry Pi and the thermostat terminal. Essentially, the Rpi will be replacing my ...
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1 vote
1 answer
142 views

Thermostats outputs to GPIO then to Furnace

I have a question on how to safely connect and detect Thermostats outputs to Controller's GPIO inputs (RasPi and BeagleBone). I've been looking up a lot and most of the cases it is showing me how to ...
1 vote
2 answers
876 views

Relay or optocoupler to switch thermostat wires

I'm doing a project to replace my thermostat with a DIY one. I'm trying to figure out how to switch the heating/cooling/fan/humidity wires. I'm inclined to go with an optocoupler like the 4N35. It ...
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1 vote
2 answers
91 views

External fan to come on when AC unit comes on.

I want to have an additional 120v fan come on when the AC unit is on. Am I able to wire that off the thermostat somehow?
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1 vote
2 answers
2k views

Can I take DC directly from W1209 Thermostat board?

I want to make an incubator. So I am using W1209 thermostat. I want to control AC and DC. I can control AC (220v AC) by the relay output. Can I control DC by connecting DC directly from the relay ...
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0 votes
1 answer
282 views

Replace copper capillary thermostat with digital temperature controller relay

Our lab has an old New Brunswick Model G25 incubator shaker. Its temperature control function is broken lately. We would like to replace the two copper capillary thermostats with modern digital ...
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3 votes
1 answer
158 views

What could be this particular thermometer used for?

I came across this rather strange looking thermometer. It seems to have two scales and some kind of wires inside it. There are two terminals at the top. Is it a thermostat? But it seems to be too ...
0 votes
3 answers
260 views

"Sniffing" into a Boiler's LED panel (Central Heating)

I've built an esp8266 based web thermostat to control my heating system. Everything seems to be working fine for the moment :) What I want to accomplish is "sniff" or intercept the boiler´s status ...
15 votes
6 answers
5k views

What is the reason for a fuse next to a thermostat?

I'm repairing a heater that someone threw in the trash (this model): It has an internal thermostat next to the heating wires, plus a thermal fuse. What is the reason for a fuse in addition to the ...
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-3 votes
1 answer
150 views

HVAC heating control with thermostat, on/off or continuous? [closed]

I have a honeywell rth8580wf heating thermostat. I wonder what the output of the "white" terminal is (heating control). Is it only going from 0V to 24V or is it continuous depending on the room ...
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0 votes
1 answer
354 views

Bimetallic Thermostat

I have a One Shot Type Thermostat CS-7TA-35 195 6103 that i've removed from a laser printer's fuser unit. There was a paper jam within the fuser unit which I assume tripped this "one shot" by metalic ...
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2 votes
3 answers
249 views

heating element for miniature working oven

Please don't laugh but I am building a small working oven for my daughter and need a heating element that can heat it from 70 to 220 degrees celsius via a thermostat. I've found this heating element ...
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