Troubleshooting High Coil Temp Reading | York Chilled Water Air Handler
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- เผยแพร่เมื่อ 9 เม.ย. 2024
- Got a work order to repair/replace high coil temperature thermistor and end up finding more issues. #airconditioning #hvac #chiller #temperature
- แนวปฏิบัติและการใช้ชีวิต
That long sensor probe, I almost thought it was an "April Fools" joke.. (( or an automatic transmission dipstick ))..
Lol, I didn’t expect 8ft long for sure. 👍
The joke is the engineer who spec'd that. The thermistor was at the far end, so the effect is the exact same thing as the short replacement probe used in the repair.
That long sensor tube is crazy! You mentioned some kind of bypass earlier in the video, but I couldn't quite make out what you said. May I ask what it was called?
I was also quite surprised to see that the air inlet was just open to the room like that. I'm guessing that room has some means by which return air can come in? (I thought I saw some dampers at the end that looked as though they just opened into the room for that purpose...) Any idea why that was done in such a way?
Thanks for asking, I was referring to the Face/Bypass air dampers on the coil inlet . There are 2 open return ducts that enter the air handler room at the top of 2 walls. There’s also outside air duct w/dampers entering through the ceiling from roof . The whole room is basically return air
Good job tech
Hey Silentonevictor, Thanks 👊
Nice work Subcool.
Thanks Steven! 👍
Pulling the original temp sensor out had me dying 😂
You could always get an 8ft mixing tube with a 12” sensor
Yeah, we got a good laugh the rest of the day 🤣
Happy Eid Mubarak ❤🎉
Great Video. Thank you for sharing. What is software you're using ? how is connect computer laptop to Air Handler ?
We use a private ip network for EMS through WiFi. It’s cloud based , no software installed on my end
Be careful just replacing the sensor because there is a difference in resistance in type 2 and type 3 10 k sensors I know this because I installed a type 3 sensor in place of a type 2 on a hot deck cold deck ahu with alerton building control and it was always hunting to satisfy the zones due to the temperature to resistance differences between the two sensors. You can find charts online explaining the difference
Good point 👊Thanks Christopher, these were both type 3 sensors. The type 2 would read higher ohms and colder temp as the temp drops below 77.
I think for the temp probe the short one is just fine. It looked like that long one has the thermistor at the far end, which in the airflow path is the exact same thing as the short one. Your measurements showed it is working fine, if it ain't broke why fix it (again)?
I wouldn't waste your time and the customer's money ordering the 8 foot one, just to end up with the exact same results. Or at worst, I'd get one that is say 2 or 4 feet long at the most.
Another point... does that software report extreme out of range temps? I worked with some TRANE systems and they did not alarm if a sensor failed...
I’m with you on that, I think the 24” sensor would be sufficient. Currently they don’t have extreme temp alerts enabled but it’s available from what I can tell. Usually we just get no cool or too cold work orders and figure it out from there. I appreciate your advice 👍
Are they also using that averaging sensor as freeze protection? Worst case, you could get 4 of the kind you have and wire them as a series/parallel circuit to average it out on the controls. Awesome video as always. Keep it coming
I don’t think it’s for freeze protection, it looks like they want the average temperature across coil, There are no access panels to that section of the coil other than unbolting the sealed panels, they even have expanded metal separating the blower section from the coil and pan. I ordered the same 8ft thermistor to stay in design . I see access doors being installed in the future 🤣
@@subcoolHVAC definitely access panels would be an excellent option.
Can you explain the top and bottom scale adjustment you made? I know its a 0-10vdc to drive the actuator but thats about it...
Sure, normally on this system 2vdc would be the low end allowing the actuator to drive closed and 10vdc the top end which is 100% open. I compared this setup to a neighboring ahu to verify. Not sure how it got this way. Thanks for asking 👍
@@subcoolHVACso they had the scale reversed? Thank you for answering👍
Yes to match the direction selected on the belimo actuator.
Dont touch the bare meter probes with your fingers when measuring the sensors. It will throw off the readings.
It’s minimal if it does and this one was definitely bad, Thanks for commenting 👍
That’s a looooooooooooooooooooong sensor
Absolutely 👍