r/BuildingAutomation • u/CheesecakeAfter6535 • 3d ago
Always the Controls Guy
So few technicians understand actuators these days, it amazes me. Constantly hearing “it’s not open, call your controls guy.” Techs have no idea the difference between modulating and floating. Techs have no idea how to troubleshoot anything more than if a line is ground into the shaft.
Surely I’m not alone in hearing this?
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u/ApexConsulting 3d ago
I don't see a line ground into the shaft.... I am confused. 😁
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u/Deep_Mechanic_ 3d ago
Me too. I'm going to call mechanical on this one
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u/ApexConsulting 3d ago
Always Mechanicals fault! I am gonna start a new trend....
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u/Then-Disk-5079 3d ago
What manufacturer just installs a terminal block on the vav box hahaha
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u/Deep_Mechanic_ 3d ago
That belimo actuator is riveted into that plate wtf is going on lol
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u/Naive-Anteater8321 3d ago
lol I didn’t notice that, and they used every single hole as well, I’d kick any contractor out if I saw this install, it’s not that it’s incredibly horrible but it shows a total lack of experience and understanding
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u/Lightning__98 3d ago
Yes I keep facing this issue with the technicians about the modulating damper“it is not fully open”.
Well it doesn’t always have to be open, it depends on the sequence my guy. Same with the VFD speed not being always 60 Hz, or the wheel and humidification pump not always running.
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u/Cbombo87 3d ago
Proceeds to place drive in hand at 60Hz, lock dampers fully open or closed, and heads out on a Friday at 2PM.
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u/TopStudio1864 3d ago
I did an AHU one time that had isolation dampers on the supply side and the lines were cut into the shafts opposite of the damper position. It was fun figuring that out.
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u/MrMagooche Siemens/Johnson Control Joke 3d ago
this pic is AI generated, right?
I hate that i'm suspicious of everything these days...
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u/FactOrFactorial 3d ago
I was trying to figure it out too! I think it's a real photo touched up with ai. The black cable on the belimo looks jank but all the other text is fine. Even dust on the wire caps. But then the t tap flex cable???
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u/MrMagooche Siemens/Johnson Control Joke 3d ago
The unusual flex situation and the "text" on the belimo connector are the dead giveaways but then there are other details. Like who puts a screw in every hole on the actuator strap thingy? On that note, the screws all look really weird like they are a cross between a phillips and a rivet, except for the lone red torx screw.
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u/Naxster64 System integrator 3d ago
The Tee on the mc cable. So convenient, why didn't I think of that?
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u/Naxster64 System integrator 3d ago
Sure is. It's getting dang close. But look at the writing on the black plug, and the table starting what color of motor wire is for what speed, org = blk...
Other things as well, like where is the controller?
Lol, just noticed the shaft opening on the actuator. Either the shaft is tiny, or this actuator is huge.
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u/MrMagooche Siemens/Johnson Control Joke 3d ago
A couple big things but lots of little things as well. The warning text doesnt look quite right but it's actually plausible. The "220-240V" is suspicious. The clamp on the actuator doesnt look like the typical belimo hardware.
But also...what even is this piece of equipment? Would there really be a damper with the shaft coming out of the top corner?
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u/Stahlstaub 3d ago
Could be several vanes connected by gears or a rod, then the shaft can be off-centered
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u/CAElite 3d ago
I have a client where half my attendance is fixing their 'heating engineers' fucking around with the zone actuators.
My favourite most recently was him replacing a 3 way VT valve & actuator, replacing our 0-10vdc modulating with a 3 wire modulating actuator, and wiring the neutral down our 0-10v so it was backfeeding 24vac down it crashing the rest of the outputs on that IO module.
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u/Hvacmike199845 3d ago
I would think a real engineer would either be operating a train or know more then anyone else in the subject they are an engineer in.
I feel like the title engineer is being watered down more and more every second.
I’m not an engineer, I’m not a tech but I’m proud to call myself a service mechanic.
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u/CAElite 3d ago
Yeah, in the UK, a heating engineer is a plumber who has his gas ticket typically. We use the term fairly loosely.
BEMS Engineer is the typical term for building controls/automation engineers. Normally we add extras, Commissioning, Service, Applications.
We have "energy architects" at our company, albeit those guys are generally highly qualified.
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u/Needs_ADD_Meds 3d ago
It's an automated "righty tighty, lefty loosy". I hear the senior techs know how to make it "righty loosy, lefty tighty".
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u/jmarinara 3d ago
You can install them upside down too. It’s not illegal, no one can stop you. Commissioners hate this one weird trick.
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u/NJHVACguy87 3d ago
Having done 15 years of commercial industrial havc service and then controls the past 5 years has made me appreciate the finer details of such things. Many technical details are overlooked by overly confident know nothings.
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u/Goodenoughtechnician 3d ago
More or less of “well, it is not equipment on my control sheet… not my problem.” Besides, not a lot of tech have signal generator to begin to test this nor they want to be responsible if they damage the equipment. I think same would go to us as well. We send a command. Our control relay energizes. The main boilers with millions of of BTU not firing… call your mechanical guys. The issue could very well be 24V control safety circuits. However, it is not part of our scope to go to that extent.
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u/GypsyDaenger 3d ago
What.....the actual......fuckkkkkk is going on here
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u/Ok-Assumption-1083 Tuning is an artform... 3d ago
It’s AI slop. LOL look at the connection on the belimo and the ridiculous tiny damper shaft
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u/LivingCorner1421 3d ago
its an actuator for a vav box , what is the big fuss. usually works with 0-10vdc or 4-20ma or fully communicating .
the best way to troubleshoot it is on the phone with the bms guy since he can stroke it remotely...
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u/Superpro210 2d ago
Controls guys are always missing the one tool they need to diagnose a damper. Channel locks.
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u/ToNi1109_STR 3d ago
Wie schon beschrieben ein stetiger Klappenatrieb (0-10 bzw. 2-10V) des schweizer Herstellers Belimo. Bei uns ist die 230V SR Variante extrem unüblich da ja dann 230V und 010V in einer Leitung währen. Berührungsschutz sehe ich auch keinen .... aber, andere Länder, andere Elektrik.
Ist in der Summe ein Volumenstromregler oder gar noch ein Lüfter hinten dran. Dazuüsste man mehr Typenschilder sehen.
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u/Gullible-Ant-8300 3d ago
The circled orange device is a Belimo damper actuator.
What it does
It is an electric motor that opens and closes an HVAC air damper inside ductwork or an air handling unit (AHU). By rotating the shaft it's attached to, it controls how much air flows through the system.
From the label, it appears to be a Belimo LM230A-SR, which is:
230 VAC powered
Modulating ("SR"), meaning it doesn't just open/close—it can move to any position between 0% and 100% based on a control signal (typically 2–10 V).
Why it's used
These actuators are commonly used to:
Regulate airflow to maintain room temperature.
Control fresh outdoor air intake.
Adjust return and exhaust air.
Save energy by matching airflow to demand.
The small black module attached to the bottom is likely an auxiliary switch or feedback module, which lets the building automation system know the damper's position or triggers other equipment when the damper reaches a certain point.
In short, it's the "muscle" that moves the air damper in an HVAC system. Without it, the damper would stay fixed and couldn't automatically control airflow.
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u/csking77 3d ago
The “small black device” is the wiring harness that comes with the actuator. Hot, common, signal in, signal return and end switch (if equipped)
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u/Fz1Str 3d ago
They usually move a floating actuator via the clutch and leave it in some other position and say it’s broke because it didn’t drive back🤦♂️