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How common are outdoor reset sensor faults?

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Teemok
Teemok Member, Email Confirmation Posts: 511
Excluding goofy wiring problems. How many bad OD sensors do you guys find? Are some brands more problematic? I like setting up a curve. Add value I can offer over the guys who don't know how or don't care. In the climate I'm in, it's not a wide curve and I find them setup questionably regularly. When I do I fell obligated to ask the customer if they want to pay me to change it. Then, I'm on the hook for the performance of a system that I have just seen for the first time and have no profit relationship with. The profit killer is when a sensor fails on warranty or just out of. In the early 2000's I had rash of failures that made me re-think the value to the customer and the liability to me. If I can heat a space with a high level of comfort without it, why risk the fault to save some small %. The service call, the wealthy can afford but leaving them cold and that being on my reputation is a problem. You might think, well the sensor failing isn't my fault, they don't/can't blame me. Oh! but they do! I have clients who are into it and understand with added components faults will happen and those are the people I set it up for. Others I'm on the fence about. Some on here feel it's a crime to not be using it with a mod-con. If I'm condensing with out it, I don't see it as a big deal. If I can rely on solid tech I'd be more inclined. I haven't had many fail recently but other tech's and some contractors I know complain they are a common issue and they disconnect them or refuse to install them. What's the word?

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  • kcopp
    kcopp Member Posts: 4,443
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    Really the only time I have seen them fail is when the siding or deck guys pull them off, dont reattach and they fill w/ water...
    Teemok
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,099
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    What does excluding Goofy have to do with wiring stuff. If I were him, I would tell all my friends at Disney to boycott your company.


    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    Teemok
  • Teemok
    Teemok Member, Email Confirmation Posts: 511
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    Wow, Ed. Thanks for that creativity. You are so good. I do enjoy comedy. I knew that was the wrong descriptor.
  • hot_rod
    hot_rod Member Posts: 22,260
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    Teemok said:

    Excluding goofy wiring problems. How many bad OD sensors do you guys find? Are some brands more problematic? I like setting up a curve. Add value I can offer over the guys who don't know how or don't care. In the climate I'm in, it's not a wide curve and I find them setup questionably regularly. When I do I fell obligated to ask the customer if they want to pay me to change it. Then, I'm on the hook for the performance of a system that I have just seen for the first time and have no profit relationship with. The profit killer is when a sensor fails on warranty or just out of. In the early 2000's I had rash of failures that made me re-think the value to the customer and the liability to me. If I can heat a space with a high level of comfort without it, why risk the fault to save some small %. The service call, the wealthy can afford but leaving them cold and that being on my reputation is a problem. You might think, well the sensor failing isn't my fault, they don't/can't blame me. Oh! but they do! I have clients who are into it and understand with added components faults will happen and those are the people I set it up for. Others I'm on the fence about. Some on here feel it's a crime to not be using it with a mod-con. If I'm condensing with out it, I don't see it as a big deal. If I can rely on solid tech I'd be more inclined. I haven't had many fail recently but other tech's and some contractors I know complain they are a common issue and they disconnect them or refuse to install them. What's the word?

    Personal choice/ decision on your part. No question that ODR can add value on some systems. Not much technology to those sensors.

    I did start adding the lightning protection to solar controls, it goes on the collector sensor wire. A lightning hit would take out the controls occasionally. It a simple fuse, could be added to ODR sensors I suppose?

    I think Viessmann has it right in that high temperature systems have more ODR benefit.

    Perhaps on your low temperature radiant jobs it is not worth the call back or the sales spiel to the customer? :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Teemok
  • Teemok
    Teemok Member, Email Confirmation Posts: 511
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    I've been listening to repeated stories about sensor failures from people who don't really have full operational logic or really care about system efficiency. They lined up with early HTP sensor problems that I had and made me question. I've only seen one or two off sensors for years now. Glad there's nary a report here. As per usual read each situation is the right path and I'll ignore the haters and trust again. Use anti-ox on connections. Thanks for that viessmann info and feed back.
  • mattmia2
    mattmia2 Member Posts: 9,747
    edited November 2023
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    Thermistors are extremely reliable. The issues are very likely to be installation or configuration issues or PCBs that aren't soldered or designed properly.

    If the firmware is designed competently it should see that the thermistor is out of spec and ignore it if it gets shorted or disconnected, it shouldn't cause a no or insufficient heat problem. I suppose a high resistance short from being wet might be harder to detect.

    ODR's benefits are more in comfort than efficiency. There can be maybe 5% to 10% better efficiency, but keeping temps even by running long cycles at just the right temp is more of a benefit.
  • AlwaysWarm
    AlwaysWarm Member Posts: 10
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    I've had my share of bad OD sensors causing trouble. Brand-wise, it varies. Setting up a curve adds value, but the liability can be a headache. If I can keep folks warm without it, I'm all for it.
  • GGross
    GGross Member Posts: 1,070
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    I sell parts, rarely have I seen a defective outdoor sensor, or one that has failed from normal conditions. For some point of reference we sell a couple hundred vitodens boilers in a year and have sold 1 outdoor sensor, looking through the notes in the order it was misplaced during a construction project. We have been selling that brand for 20 years give or take. With that many boilers out, 1 sensor in a year, personally I am of the opinion the sensors are reliable.
    Teemok
  • Teemok
    Teemok Member, Email Confirmation Posts: 511
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    This feed back makes sense. I know the sensors are no different than any other thermistor in other places and I haven't seen those failing or even off by much. I know they are just a weld. Not much to go wrong. I have one for a tester from 87 and it's still accurate. Wiring, connections and board faults sounds right. Average coldest day around here is 36F with a record of 9F. In Maine where I waited for the bus at 5:40 am in high school the average low is 10.3F with a record of -39F.
    GGross
  • Teemok
    Teemok Member, Email Confirmation Posts: 511
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    Well I'll be, Lochinvar flue sensor on a 720K BTU commercial fire tube went bad after 2 months. 10k thermistor Ohmed out of spec too low. Lucky to have two boilers side by side. Sensor swap and the problem followed. They do fail.
  • GGross
    GGross Member Posts: 1,070
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    To be fair the flue sensor is in a much more volatile location than an outdoor sensor though. I see flue sensor failures fairly regularly
    Teemok
  • ScottSecor
    ScottSecor Member Posts: 863
    edited December 2023
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    Since I started in the 1980's, we have serviced and installed Heat Timer, Tekmar, Honeywell, Weil McClain, Peerless, HTP, Lochinvar, Laars, Hydrotherm, and a few others with outdoor sensors. Out of roughly one thousand systems with outdoor temperature sensors, I'm guessing about fifty had problems. Some were a year or two old and some were perhaps forty years old. The most reliable seemed to be the the Heat Timer units that were connected to the panels with the mechanical clock that I've soldered a few wires on a cold Sunday night.
  • Teemok
    Teemok Member, Email Confirmation Posts: 511
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    GGross said:

    To be fair the flue sensor is in a much more volatile location than an outdoor sensor though. I see flue sensor failures fairly regularly

    It is in a stainless sealed case. 150F. The heat cycling would be the notable difference.