So this wiring on the unit would have been factory wired, but if it had been commissioned as per the MI these would have been resolved. Thanks for this most interesting video which covers all these points including correction. 💯👍👍👍
New sub to your channel..I like how you work through problems and do a great job seeing "the big picture". I did a LOT of work on Trane commercial gear, with all of the controllers and BacNet and learned a lot. I am good with controls and electrical aspects, but the refrigeration side is something I don't touch, so it is nice to have channels like yours showing that side of it.
Tech support told me that under voltage will kill circuit boards. I also remember from tech school that under voltage kills motors, so the same would apply to coils…windings and coils are practically similar. So there is science behind it. I’ve had no cool calls that were fixed with a transformer tap swap, but I still tossed the contactors bc I didnt trust em lol. Always good to check the transformer taps, i see many installers leave them on 240 with 208v
The reason undervoltage would kill induction motors is they try to run at a constant speed. In a given application that means they pull a constant amount of power. If the power remains the same then the current goes up when the voltage goes down. When the current goes up the heat also goes up. I'm not quite sure how it works with AC coil relays but with DC coil relays the current is proportional to the voltage. That means you would want to decrease voltage to increase lifespan. Of course if the voltage is too low the relay won't pull in properly and that could burn up the contacts.
Had a moderately sized retail store near me that had flooded to like 6 feet a few years ago. It ran 4x 5 ton splits. 2 of the condensing units went for a swim, completely submerged. Had them run 2 units in heat and 2 in cool for a few days. Wasn't comfortable in there but damn they ripped the moisture out in no time. Good thing their power meter went for a swim too and wasn't working 😂 Surprisingly the 2 condensing units that went for a swim still worked, gave the circuit boards a drench in denatured alcohol before I turned them on but still did not expect them to survive.
Those sensors are basically a kind of diode so they are polarity sensitive, depending on the particular controller. They do still change resistance depending on temperature though, and IIRC they are NTC.
Had exactly the same thought. The glass sensor body (and the way its insides look) indicates that it is likely a diode and thus has to be wired up with correct polarity. I guess it is a Zener diode, as those can be used for temp sensing. Breakdown voltage goes down when temp rises so it does act like NTC device.
That kitchen unit that had the ecomizer open, are you sure that wasn’t done on purpose for make up air for the exhaust fans? I’ve seen this strategy used several times on newer restaurants when they are too cheap to install a dedicated MUA unit. They oversize the RTU in order to handle the extra load of pulling outdoor air. 🤦♂️
Welll like he said. If you’re tapped for 230 and only have 208. Your step down voltage is gonna be lower so as we saw 230 tapped have him 23 volts. And 208 tapped gave us 27 volts which is suitable for the board to get proper voltage. It’s necessary. this install team did terrible guys probably didn’t know what they are doing
It’s based on the incoming voltage that’s all. So you check 3 phase. Either 208. Or 230. In this instance. You tap for what’s being provided. If you don’t you’ll have issues like he is having. In this case. Board is bad and more then likely that suction line sensor is bad or not installed into the right terminal on board. Seen it many times now it’s becoming a problem with York and dudes who don’t know what they are doing
I mean, if there is an active wildfire, (unfortunately common in too much of the world now,) would ya want that arbitrarily brought in as "fresh air?" It's not ALL horsecrap, y'know.
That should trip a smoke detector, I would hope. But if there was an active wildfire nearby, I would be worried about being trapped in a building not breathing clean air. But this was a kitchen, so there should have been a make up air unit somewhere bringing in air to negate some of the exhaust fans negative pressure. Those are not gonna shut off due to poor air quality, they will only shut down if there's a fire alarm.
As an electronics engineer, a thermistor is not polarity sensitive at all and are not a kind of diode but simply a resistor that changes its value with temperature. The change in the reading is most likely due to the change in self-heating of the sensor caused by the increase in voltage from when you changed the 24V transformer taps. Increasing the voltage will increase the current through the sensor and therefore the self-heating of the thermistor which will result in an increase in the temperature reading. It is also worth noting that on a two-wire sensor the reading is dependent on the electrical parameters of the entire circuit from the controller to the sensor and back again. A three-wire thermal sensor has an extra wire that enables the temperature controller to compensate for the cable run to the sensor so it only reads the value determined by the thermistor.
As someone who has actually worked on Trane equipment and been in electronics for many decades, that particular device IS a semiconductor based design, and is not purely resistive. The junction varies its resistance based on temperature, yes, BUT being a semiconductor and, in this case, not designed as non polarized, it WILL give erroneous readings if connected in "reverse polarity". I discovered this on one of my first installs where I had this same issue, which was corrected by reversing the polarity just as the uploader did. (And it was over multiple rooms, so I had a LOT of wiring to swap.) Now, let's assume (and we all know what happens when you assume) that you are correct. Please explain WHY reversing the polarity fixed the issue, when we all know that RESISTORS are NOT polarity sensitive. And this; " Increasing the voltage will increase the current through the sensor and therefore the self-heating of the thermistor which will result in an increase in the temperature reading." In a properly designed controller (which if you are an engineer you should already know this) the voltage (or current) supplied to ANY type of sensor is set by a tightly regulated supply or reference. It will NOT be affected by variations in incoming controller power supply voltages, otherwise it would drift constantly in accuracy based on the variations in incoming supply voltage. That makes it useless as a sensor. And this: "The change in the reading is most likely due to the change in self-heating of the sensor caused by the increase in voltage from when you changed the 24V transformer taps." See above. And also, unless I missed something, that false reading persisted AFTER he changed the taps, and was finally fixed when the polarity was swapped. (And proven to be right, based on his observation that the faulty sensor was wired differently from the working one on the other unit.) I finally ask you sir, how much REAL WORLD experience do you possess? As in actually INSTALLING and TROUBLESHOOTING equipment such as this? Oh, and your no content, no subscriber channel (since 2008, really?) gives you little to no credibility.
@@mxslick50 Thanks for taking the trouble to post such a detailed reply my comment. While it is true that purely resistive sensor such as a thermistor has no polarity, and active sensor or one based on an active component (which in electronics means a semiconductor junction) will have a polarity which must be observed. Any two-wire sensor, whether it be measured by a voltage or a current is dependent on the quality of the wiring and connections to it. Therefore any change to the connections or wiring will affect the overall sensing circuit it two ways. Firstly, there will be a change in the overall loop resistance of the circuit due to the physical alteration. Secondly, this change will alter the self-heating of the sensor and therefore also affect the overall sensing circuit. I have looked at the video again and the sensing element is clearly marked 'R1', which in electronics denotes a resistor. And the sensing element does have the appearance of a glass-sealed axial lead thermistor of the type specifically designed for HVACR applications. Changing the wires over would have no effect on a simple thermistor. Based on the evidence presented in the video, the traces are just visible in the sensor and they look to go directly to the screw-down terminations and the thermistor appears to be the only component on the circuit board. My conclusion, therefore, is that swapping the polarity at sensor shown in the video in itself did nothing: The problem was solved by the reconnection of the wires fixing a bad connection either in the screw-down terminals or the physical act of doing so improving a dry solder joint in the sensor. If the sensor does have a dry joint, then ideally it would need either replacement or repair.
The resistance of the contactors is not going to increase with age. Ever. The only increase in resistance can be from connection oxidation at the terminals. From the ANSI C84.1 voltage tolerance standard the voltage of a 24V system should be between 21.6 and 25.2 volts: Anything above or below this is out of specification. From Voltage Tolerance Standard ANSI C84.1:- Range A - Normally expected voltage tolerance: Service voltage: Normal voltage tolerance +/-5% for systems at or below 600V. At 24VAC this is between 22.8VAC and 25.2VAC. Utilization Voltage: End-user equipment should provide full performance at +5/-10% of nominal voltage on systems at or below 600V. At 24VAC this is between 21.6VAC and 25.2VAC The utilization equipment (loads) are expected to function and provide full satisfactory performance for range A voltage tolerance. Range B - Voltage tolerances that should be limited in extent, frequency and duration (Range B). Measures should be taken within a reasonable time fram to get back to Range A: Service voltage: Allowable tolerance +5.8/-8.3% for systems at or below 600V. At 24VAC this is between 22.0VAC and 25.4VAC Utilization voltage: Allowable tolerance +5.8/-13.3% for systems at or below 600V. At 24VAC this is between 20.8VAC and 25.4VAC End user equipment should be designed to provide acceptable performance for voltages in range B, although not necessarily as good performance as in range A. Note that there is more tolerance BELOW the nominal voltage than above.
"The resistance of the contactors is not going to increase with age. Ever. The only increase in resistance can be from connection oxidation at the terminals. " Once again, you are talking out of your behind. Coil resistances of contactors WILL change, depending on many factors, including temperature and if the magnetic gap between the coil and the moving contact structure increases (due to rust or debris) and any damage from overheating from over (or under) voltage. The main failure modes I have run into with motor starters and contactors are drops in resistance (coil insulation breakdown) or fully open coils (which is a very massive INCREASE in resistance. ) You seriously exhibit all the classic signs of an engineer who has never actually worked in the real world on equipment. I do give you credit for quoting the ANSI specs, that is very helpful information. That is well done.
@@mxslick50 'Once again, you are talking out of your behind'... Actually I'm not. I have qualifications in both electronics and electrical engineering which means I understand the properties of a coil of wire and its electromagnetic field as well as the difference between resistance and reactance. If you'll allow me to explain... Firstly, any change in resistance of the coil with temperature is negligible in this situation. Coil failure due to overheating, either open or short circuit, is most likely due to overvoltage in the first place or heat from the load contacts being thermally conducted into the coil. This would result in the failures you describe. While I accept that it is possible to measure a change in resistance at the coil terminals due a particular failure, and have never stated otherwise, it is not the resistance of the wire that makes up the coil winding that has changed but the properties of the coil when considered as a whole that have changed. In neither an open or a short circuit have the actual properties of the copper wire itself changed yet the properties of the coil when considered as a whole have, and this is what you are referring to when you describe your own experience. The only thing that can change, due to external factors, is the reactance which is dependent on the frequency of the voltage into the coil and the presence or absence of ferrous material within the coil, although this again will only be a slight change and allowed for by design.
So this wiring on the unit would have been factory wired, but if it had been commissioned as per the MI these would have been resolved. Thanks for this most interesting video which covers all these points including correction. 💯👍👍👍
Nice troubleshooting Bill ... Good to have you back at it ... Thx
New sub to your channel..I like how you work through problems and do a great job seeing "the big picture". I did a LOT of work on Trane commercial gear, with all of the controllers and BacNet and learned a lot. I am good with controls and electrical aspects, but the refrigeration side is something I don't touch, so it is nice to have channels like yours showing that side of it.
Nice work Bill.
Thanks for sharing. Wifey & I heading to Melvindale tomorrow! Home to world famous Hops & Barley, lol😅
Bungie cord to a strong hook magnet to keep the door open. Will fit right into your bag.
Tech support told me that under voltage will kill circuit boards. I also remember from tech school that under voltage kills motors, so the same would apply to coils…windings and coils are practically similar. So there is science behind it. I’ve had no cool calls that were fixed with a transformer tap swap, but I still tossed the contactors bc I didnt trust em lol. Always good to check the transformer taps, i see many installers leave them on 240 with 208v
The reason undervoltage would kill induction motors is they try to run at a constant speed. In a given application that means they pull a constant amount of power. If the power remains the same then the current goes up when the voltage goes down. When the current goes up the heat also goes up.
I'm not quite sure how it works with AC coil relays but with DC coil relays the current is proportional to the voltage. That means you would want to decrease voltage to increase lifespan. Of course if the voltage is too low the relay won't pull in properly and that could burn up the contacts.
Their in dehum mode 😂
Had a moderately sized retail store near me that had flooded to like 6 feet a few years ago. It ran 4x 5 ton splits. 2 of the condensing units went for a swim, completely submerged.
Had them run 2 units in heat and 2 in cool for a few days. Wasn't comfortable in there but damn they ripped the moisture out in no time. Good thing their power meter went for a swim too and wasn't working 😂
Surprisingly the 2 condensing units that went for a swim still worked, gave the circuit boards a drench in denatured alcohol before I turned them on but still did not expect them to survive.
Those sensors are basically a kind of diode so they are polarity sensitive, depending on the particular controller. They do still change resistance depending on temperature though, and IIRC they are NTC.
Had exactly the same thought. The glass sensor body (and the way its insides look) indicates that it is likely a diode and thus has to be wired up with correct polarity. I guess it is a Zener diode, as those can be used for temp sensing. Breakdown voltage goes down when temp rises so it does act like NTC device.
I unfortunately work on some of these units going to have to try it opening up that panel now 😂
Nice video, thanks for sharing
❤
Great video. Fun to see all the old restaurants I used to work at.
What’s with all these york units on peoples videos?!
That kitchen unit that had the ecomizer open, are you sure that wasn’t done on purpose for make up air for the exhaust fans? I’ve seen this strategy used several times on newer restaurants when they are too cheap to install a dedicated MUA unit. They oversize the RTU in order to handle the extra load of pulling outdoor air. 🤦♂️
This is great content! Who is this new youtube guy? 😅.
Great job bill
What is the process of re-tapping? I've only dealt with residential.
Welll like he said. If you’re tapped for 230 and only have 208. Your step down voltage is gonna be lower so as we saw 230 tapped have him 23 volts. And 208 tapped gave us 27 volts which is suitable for the board to get proper voltage. It’s necessary. this install team did terrible guys probably didn’t know what they are doing
It’s based on the incoming voltage that’s all. So you check 3 phase. Either 208. Or 230. In this instance. You tap for what’s being provided. If you don’t you’ll have issues like he is having. In this case. Board is bad and more then likely that suction line sensor is bad or not installed into the right terminal on board. Seen it many times now it’s becoming a problem with York and dudes who don’t know what they are doing
Got my sub!!!
👍👍👍
nice vid Bill!
A york with LG compressors and microchannel? Thats rough.
Why did they use LG compressors !!
Or a magnet?
Outdoor air quality sensor! The shit they put on equipment these days. So what, if the smog is heavy, it shuts off the unit?
I mean, if there is an active wildfire, (unfortunately common in too much of the world now,) would ya want that arbitrarily brought in as "fresh air?" It's not ALL horsecrap, y'know.
That should trip a smoke detector, I would hope. But if there was an active wildfire nearby, I would be worried about being trapped in a building not breathing clean air. But this was a kitchen, so there should have been a make up air unit somewhere bringing in air to negate some of the exhaust fans negative pressure. Those are not gonna shut off due to poor air quality, they will only shut down if there's a fire alarm.
Why does that unit have 3 transformers
90 thumbs up
As an electronics engineer, a thermistor is not polarity sensitive at all and are not a kind of diode but simply a resistor that changes its value with temperature. The change in the reading is most likely due to the change in self-heating of the sensor caused by the increase in voltage from when you changed the 24V transformer taps. Increasing the voltage will increase the current through the sensor and therefore the self-heating of the thermistor which will result in an increase in the temperature reading.
It is also worth noting that on a two-wire sensor the reading is dependent on the electrical parameters of the entire circuit from the controller to the sensor and back again. A three-wire thermal sensor has an extra wire that enables the temperature controller to compensate for the cable run to the sensor so it only reads the value determined by the thermistor.
As someone who has actually worked on Trane equipment and been in electronics for many decades, that particular device IS a semiconductor based design, and is not purely resistive. The junction varies its resistance based on temperature, yes, BUT being a semiconductor and, in this case, not designed as non polarized, it WILL give erroneous readings if connected in "reverse polarity". I discovered this on one of my first installs where I had this same issue, which was corrected by reversing the polarity just as the uploader did. (And it was over multiple rooms, so I had a LOT of wiring to swap.)
Now, let's assume (and we all know what happens when you assume) that you are correct. Please explain WHY reversing the polarity fixed the issue, when we all know that RESISTORS are NOT polarity sensitive.
And this; " Increasing the voltage will increase the current through the sensor and therefore the self-heating of the thermistor which will result in an increase in the temperature reading." In a properly designed controller (which if you are an engineer you should already know this) the voltage (or current) supplied to ANY type of sensor is set by a tightly regulated supply or reference. It will NOT be affected by variations in incoming controller power supply voltages, otherwise it would drift constantly in accuracy based on the variations in incoming supply voltage. That makes it useless as a sensor.
And this: "The change in the reading is most likely due to the change in self-heating of the sensor caused by the increase in voltage from when you changed the 24V transformer taps."
See above. And also, unless I missed something, that false reading persisted AFTER he changed the taps, and was finally fixed when the polarity was swapped. (And proven to be right, based on his observation that the faulty sensor was wired differently from the working one on the other unit.)
I finally ask you sir, how much REAL WORLD experience do you possess? As in actually INSTALLING and TROUBLESHOOTING equipment such as this? Oh, and your no content, no subscriber channel (since 2008, really?) gives you little to no credibility.
@@mxslick50 Thanks for taking the trouble to post such a detailed reply my comment.
While it is true that purely resistive sensor such as a thermistor has no polarity, and active sensor or one based on an active component (which in electronics means a semiconductor junction) will have a polarity which must be observed.
Any two-wire sensor, whether it be measured by a voltage or a current is dependent on the quality of the wiring and connections to it. Therefore any change to the connections or wiring will affect the overall sensing circuit it two ways. Firstly, there will be a change in the overall loop resistance of the circuit due to the physical alteration. Secondly, this change will alter the self-heating of the sensor and therefore also affect the overall sensing circuit.
I have looked at the video again and the sensing element is clearly marked 'R1', which in electronics denotes a resistor. And the sensing element does have the appearance of a glass-sealed axial lead thermistor of the type specifically designed for HVACR applications.
Changing the wires over would have no effect on a simple thermistor. Based on the evidence presented in the video, the traces are just visible in the sensor and they look to go directly to the screw-down terminations and the thermistor appears to be the only component on the circuit board. My conclusion, therefore, is that swapping the polarity at sensor shown in the video in itself did nothing: The problem was solved by the reconnection of the wires fixing a bad connection either in the screw-down terminals or the physical act of doing so improving a dry solder joint in the sensor. If the sensor does have a dry joint, then ideally it would need either replacement or repair.
Hey the gages you stole from your old boss
That board is no good. York units with boards from 2020 are no good. You can either update the board or replace it
Also the suction sensor will give you the freeze stat
Pretty sure this channel is dead hasn't posted anything in 2 months
The resistance of the contactors is not going to increase with age. Ever. The only increase in resistance can be from connection oxidation at the terminals. From the ANSI C84.1 voltage tolerance standard the voltage of a 24V system should be between 21.6 and 25.2 volts: Anything above or below this is out of specification.
From Voltage Tolerance Standard ANSI C84.1:-
Range A - Normally expected voltage tolerance:
Service voltage: Normal voltage tolerance +/-5% for systems at or below 600V. At 24VAC this is between 22.8VAC and 25.2VAC.
Utilization Voltage: End-user equipment should provide full performance at +5/-10% of nominal voltage on systems at or below 600V. At 24VAC this is between 21.6VAC and 25.2VAC
The utilization equipment (loads) are expected to function and provide full satisfactory performance for range A voltage tolerance.
Range B - Voltage tolerances that should be limited in extent, frequency and duration (Range B). Measures should be taken within a reasonable time fram to get back to Range A:
Service voltage: Allowable tolerance +5.8/-8.3% for systems at or below 600V. At 24VAC this is between 22.0VAC and 25.4VAC
Utilization voltage: Allowable tolerance +5.8/-13.3% for systems at or below 600V. At 24VAC this is between 20.8VAC and 25.4VAC
End user equipment should be designed to provide acceptable performance for voltages in range B, although not necessarily as good performance as in range A.
Note that there is more tolerance BELOW the nominal voltage than above.
"The resistance of the contactors is not going to increase with age. Ever. The only increase in resistance can be from connection oxidation at the terminals. "
Once again, you are talking out of your behind. Coil resistances of contactors WILL change, depending on many factors, including temperature and if the magnetic gap between the coil and the moving contact structure increases (due to rust or debris) and any damage from overheating from over (or under) voltage. The main failure modes I have run into with motor starters and contactors are drops in resistance (coil insulation breakdown) or fully open coils (which is a very massive INCREASE in resistance. )
You seriously exhibit all the classic signs of an engineer who has never actually worked in the real world on equipment.
I do give you credit for quoting the ANSI specs, that is very helpful information. That is well done.
@@mxslick50 'Once again, you are talking out of your behind'... Actually I'm not. I have qualifications in both electronics and electrical engineering which means I understand the properties of a coil of wire and its electromagnetic field as well as the difference between resistance and reactance. If you'll allow me to explain...
Firstly, any change in resistance of the coil with temperature is negligible in this situation. Coil failure due to overheating, either open or short circuit, is most likely due to overvoltage in the first place or heat from the load contacts being thermally conducted into the coil. This would result in the failures you describe.
While I accept that it is possible to measure a change in resistance at the coil terminals due a particular failure, and have never stated otherwise, it is not the resistance of the wire that makes up the coil winding that has changed but the properties of the coil when considered as a whole that have changed. In neither an open or a short circuit have the actual properties of the copper wire itself changed yet the properties of the coil when considered as a whole have, and this is what you are referring to when you describe your own experience.
The only thing that can change, due to external factors, is the reactance which is dependent on the frequency of the voltage into the coil and the presence or absence of ferrous material within the coil, although this again will only be a slight change and allowed for by design.