It's called job security 😊

Electrical engineer here- yes, it is induction/induced voltage that causes voltage on one wire from another. Induced voltage depends on the current (amps) going through the primary wire, frequency of the AC voltage in the primary wire, length the wires run parallel, and distance between the wires. I’m guessing the current is low on the primary wires, and if the frequency is line frequency (60hz), which is also relatively low, I doubt there’d be much voltage on the secondary wire. The bigger problem is thermostat wire insulation is not rated for 208/240V, which is a real problem. It could easily wear away and short. It also probably isn’t sized correctly for the circuit breaker/fuse so it could easily start a fire.

@billbrowning3021

Жыл бұрын

Line voltage on a control circuit. Yikes.

@qomco

Жыл бұрын

That last paragraph is a huge understatement.

@denverbraughler3948

Жыл бұрын

You are correct that induction requires current and there is hardly any current. Did you study parasitic capacitive coupling? That effect requires only AC potential.

@lgunderso2117

Жыл бұрын

@@denverbraughler3948 yes, but the frequency is so low and the wires are so far apart it’s negligible in this application.

@misterhat5823

Жыл бұрын

In this case, capacitance and leakage resistance or much more likely to give a measurable voltage than induction.

If I ever own my own restaurant equipment repair company, I will hopefully do the same as you do. I have gotten so much information from a guy who made his internal training videos public. Thank you Chris.

i've had a few of those electrical WTF moments at work before -- "wait, wait, wait, wait..." lol

@HVACRVIDEOS

Жыл бұрын

I will discuss this on my Livestream this evening 3/20/23 @ 5:PM (pacific) over on KZread come over and check it out kzread.infovKpJKA-Y51U

Nice video. TAB guy here. Been testing those detectors for many years. The sampling tube with the holes faced into the airstream and capped off at the end takes in the total pressure. The open tube, the static pressure. The difference will be the velocity pressure. Notice the detector label will typically require a water column range of 0.015"-1.20". When the detector trips, the unit needs to shut down less that 15 seconds. Find them wired in all kinds of ways. But through the high voltage side, yikes. Could writes pages...

As dual trained in juice and HVAC, I see techs often that are mesmerized by digital signals, AC and DC riding on same cable (Mitsubishi controls) and smoke detectors.

@qomco

Жыл бұрын

It is pretty wild to have 2 signals running independently on the same set of wires. Especially considering the DC is a pretty cleaned up comm signal

Get involved one of our techs recived a severe shock grabbing a low voltage wire having 120 on it.

Bit of a random thing, but when you're using a stereo pickup mic you might want to consider either mixing the audio down to mono or using a stereo imaging filter set to shift the sides to the mid a fair bit. Otherwise headphone users get 20 minutes of you talking in their right ear :P Additional tip: if you add a high-pass filter (cutoff set to around 80Hz) to the stereo audio before downmixing to mono, it reduces a lot of the weird rumbling and phase interference issues on the low end. Really helps with the speech clarity.

I feel like it's possible the smoke detector downstairs was installed by an alarm company and not an HVAC company, either as a retrofit or a new alarm company. THAT tech probably doesn't understand Lennox industrial air conditioners.

What's funny is on those Prodigy M2 boards the purple 3 wire plug can be configured to provide alarm signaling with supervisory loop configuration. They went the long way to reach their elbows and added another failure point.

5:19 it took a couple years but THANK YOU!!!!!! LOL

@HVACRVIDEOS

Жыл бұрын

ha ha

I'd bet that Chris is looking up induction and impedance as soon as he got off of the video, because he's just like me, when he gets his mind on something, he won't stop until he has an answer! 😂 Great video as always brother.

Hi Chris. Another great video! A great example of the NECESSITY for proper training!! So many times in my career my boss would give me the old "getting thrown to the wolves is the best way to learn." I have zero empathy for a boss or owner who believes that nonsense!! You've said it many times. This channel is just the ramblings of your brain. Not an instructional channel. That being said. I've learned so much watching you!! I've said it before, but it bears repeating, THANK YOU for what you do!! The popularity of your channel is not an accident. If you we're just some cornball doing dumb things, not gonna be popular. There's a lot of junk on KZread! You and Rick from HVACR Survival are the two guys I admire the most. I look forward to your videos and I watch to the end every time! ✌🏻🤘🏻😁😎

I love Lennox units but when they went to The Prodigy board the first generation was crap. They replace thousands of them under warranty. I had 230 stores in California. We replace them all the time the newer ones are much better.

Hey thank you for correcting yourself. I'm not one of the "crazy people" as you call it😂. I do like that you correct yourself on the terms because you teach me the proper terms. In the end it just makes me a slightly better tech. So thanks brother.

Please upload more videos. Great work.

When you were looking at that drain trap on that RTU with the vent and said Dummies I literally laughed so hard because I just love the way your brain works hahaha. Chris you're so awesome man. Haha

Another thorough, professional job. I love the way you talk us through your thought process while troubleshooting. You’re a great role model for the younger techs and some of us older techs as well. Thank you.

You had mentioned in the video of possibly bypassing the return smoke detector. Here in the Northeast, depending on the CFM of the unit it’s required for return and supply smoke detector and you would have to check with your local codes for your area. As always a great informational video.

Yeah, induction. But a Low-Z (impedance) mode on a multimeter will tell you if there's any TRUE voltage on there or just ghost / induced voltage (as soon as you apply a load it might shoot to zero volts on those induced wires).

Looking at the 18AWG thermostat wire, the max voltage is 150V before the insulation could break down. That was very dangerous if a tech were downstairs and touched those low voltage contacts, not expecting line voltage. It is induction. Yes you would have for sure. I have seen workers killed because of that. There was an electrician on a job that didn't follow proper procedures and was working on installing new 13.8KV high voltage lines inside a factory that had a long parallel run next to existing powered lines. He didn't have the new lines grounded properly and they had enough current / voltage induced into them, that when he touched them that he was electrocuted. I am glad I wasn't involved in that accident or the OSHA investigation that happened afterwords, we were working around the same area at the time on other things.

i hate doing restaurant's rooftops. they never want to pay for their maintenance and say it is the landlord responsibility

It's refreshing to see a young man such as yourself confident in your discovery.

Hi Chris, I have electronics training and the induced voltage in unused wires in the situation you are describing would be from what is known as 'capacitive coupling'. It is not inductive coupling because the coupling is electrostatic, not electromagnetic. A capacitor is basically two conductors separated by an insulator which is what you get when in a multi-core cable. You can demonstrate this yourself quite easily with, for example, a length of thermostat wire and a multimeter. Set your multimeter to capacitance and probe the ends of any two conductors in the wire and you will get a reading of the cable capacitance. The technical data for a cable, particularly signal cables and always with RF coaxial cables, there will be a capacitance value which is usually shown as a measured capacitance over a specific length of the cable in pF/m (picofarads per metre) or possibly pF/ft (picofarads per foot). If one conductor is wound around another conductor then you have an inductive (electromagnetic) coupling is that, from an electrical perspective, this would effectively be a transformer.Bearing this in mind could explain a 'ghost in the machine' that is in reality caused by a high power cable coupling to a small signal cable (which likely has signal amplifiers at some point in the circuitry) and causing problems. This kind of problem is particularly well known in audio engineering circles and in IT so signal and power cables are kept as separate as possible. On a personal note, when I'm diagnosing and troubleshooting I always keep an eye open for switching power supplies as I have found them a source high-frequency pulsing EMF that is so bad it even corrupts ethernet data links. As an shortened example: In an electronics store I worked at the EPOS and computer systems were running really slow,. I discovered a laptop-style power supply sitting on the ethernet cabling that was powering the ethernet switch. I managed to relocated and secure this power supply away from the cables and things immediately improved.

For that fire alarm input on the controller, you could still use it without having to get up there with a ladder and changing the contacts from NC to NO. Resistor, probably 10k, from fire alarm input to 24v. This pulls the input high (pull up resistor). Then you put your NC smoke detector contacts between common and the alarm input. As long as the alarm is healthy, it will keep the input pulled low through the NC contact. Once it trips and goes open, the resistor pulls the alarm input high and trips the unit out.

@ehsnils

Жыл бұрын

To me it looks like it's a bit strange to connect to the detector on the duct, isn't there a central fire alarm system that should command the ventilation system and not just a single detector? It could be worth to check in with the fire alarm company regarding how to wire this the best way. If there's a fire then there could be a concern that if there's people in the building then you would like to evacuate the smoke since smoke inhalation is the number one killer when there's a fire. But that's a completely different story.

@BeezyKing99

Жыл бұрын

@@ehsnils He has videos on duct detectors... if I'm not mistaken, there's at least 2 per unit.

@timothystevenson7907

Жыл бұрын

​@BeezyKing99 there can be 2 per unit but they do bring up a good point. Alot of restrants will have integration into the acts and extraction fans. Also touching fire alarm systems could put liability onto you, I seem to remember something from a video saying always check with the fire company for how they want it done.

@Bryan-Hensley

Жыл бұрын

I wouldn't touch it except bypass until the alarm company comes mainly because of liability.

@Pbell

Жыл бұрын

You could do all that technically, however the inspector will come and he will want to see the unit go dead not read smoke typically. It has always been my experience they don’t like seeing the unit still operational using logic to be controlled.

Great work, Chris. Thanks for showing us your work.

Great video, I learned something new since I rarely work on AC units

They got lucky with that thermostat wire Since the smoke detector probably never tripped, the voltage on all the 4 wires must have been the same all the time, because the relay on the smoke detector is closed If there had been 240V between 2 wires for a long time, the insulation would have broken down at some point And since no one puts smaller fuses on sub circuits but connect everything to the 80-or-so Amps main fuse, that little wire would have made a fantastic special effects show

@throttlebottle5906

Жыл бұрын

majority of t-stat wire is now rated for up to 150V, not that it should ever have that kind of voltage on it, being Class 2 rated circuitry. lol the scary part is how the outer jacket was stripped, I have seen so many with the conductor jackets all nicked into, now that would be real bad with a bit of moisture. probably right on it being held closed contacts(until tripped), so nearly zero voltage between the pair and 120V to other pairs/ground.

@gorillaau

Жыл бұрын

The wire is the fuse. Not sure how much it would take to melt it down, perhaps two to five amps.

@Bryan-Hensley

Жыл бұрын

​@@gorillaauthe wire is a heater element if not fused correctly.

@HVACRVIDEOS

Жыл бұрын

I will discuss this on my Livestream this evening 3/20/23 @ 5:PM (pacific) over on KZread come over and check it out kzread.infovKpJKA-Y51U

@inoahmann7542

Жыл бұрын

I'll never understand why nobody properly fuses anything in equiptment. I work on some units where every single fuse was bypassed when they became my responsibility. When I find units like that, I cut the power and lock out the disconnect until I can fix it. I started doing that when I found one with a short to ground that was drawing 30a through 12 awg wire. It was still running, but the bolts that held the evaporator up were hot as fire, and the paint was burned off around them.

Yeah, I completely agree I mean if you’re in Wisconsin I would’ve had you take care of my building pressure, tested it and everything else in the sun and whatever you said goals and that’s the end of it

Easy fix for your smoke, 10k resistor from +24v to the sense terminal, "normally closed" detector from 0v to sence. that way the smoke detector pulls the output low, and the 10k pullup resistor pulls it high when the detector opens. obv itd be better to get up to the detector and rewire, but could get you out a bind :)

Great Video. Thank you for sharing

Yes, it is induction. This is an issue with network and telephone cabling. If you've picked up a phone in a house (land line) and heard a buzzing after the first digit you pushed (so there's no dialtone), that's 60hz. Someone ran the phone wire next to a 120 volt house electrical wire. For network cabling, the twists are there to try to dampen the induction, but even then, just running it near a fluorescent light fixture can cause interesting effects. However, electricians will deny this repeatedly. I had one guy claiming that because his 110 volt+ meter didn't show any voltage on the ethernet cabling, there wasn't a problem. Apparently, in Houston, the union trains the electricians that if there's less than 10 volts on a line, it's not an issue to any equipment. (network equipment often hates spurious millivolts)

We had a similar situation at the company where I worked. We had a harness made by an outside company that went to a 3 phase motor. Had a shielded 3 conductor motor lead, a shielded encoder cable plus other signals and was about 6 feet long. We had a problem where the motor would go nuts at random times. Turned out the 240v motor leads were inducing enough voltage/current to light a 24v lamp from the shield to ground. We replaced the motor cable with something more substantial an the problem went away.

As a fire alarm guy, always asks AC guy what "he" needs, then wire it and test it....

Another good vid Bud ... Thx ...

Chris, technically the relays in the fire alarm are rated to break high voltage typically at low amperage which those transformers qualify as, However they needed to maintain the wire gauge for the electrical rating. When I was a fire alarm technician I was always careful to make sure I was cutting the low voltage of the transformers. But there were cases where I had to control outlets for equipment in places using high voltage contactors.

@DEW409

Жыл бұрын

Then I am sure you used wiring methods and conductors rated for line voltage. The problem here is using low voltage wire for line voltages. Not only is it not rated for that use, people are going to assume only 24 volts, the standard control voltage, and possibly get electrocuted or killed by the totally unexpected line voltage present.

@Pbell

Жыл бұрын

@@DEW409 yes that’s what I said “they needed to maintain the wire gauge for the electrical rating”. Also as a courtesy I would write high voltage in the cover of my relay so it wasn’t a surprise for the next guy. Many times I was surprised when I was electrocuted by high voltage circuits connected to the relays.

@HVACRVIDEOS

Жыл бұрын

I will discuss this on my Livestream this evening 3/20/23 @ 5:PM (pacific) over on KZread come over and check it out kzread.infovKpJKA-Y51U

In my sister's house her smoke detectors are all connected to each other. They are super annoying because the slightest puff of smoke anywhere in that place and those annoying things come on everywhere to give you tinnitus for a few minutes once they finally stop. Sometimes I swear that if someone is outside smoking within 100 feet of that place it is enough to set those sensitive things off. Once humid air that rushed in from her garage set them off that is how sensitive they are. A good fart would probably set those dang things off too LOL!!!

Woooow. Another classic sir. I’m telling you, i wish i had the knowledge you are giving us. Someday i hope. Anyways I appreciate you. Thank you

Thanks great video

I find your videos quite soothing: here's a situation, investigate the root causes, immediate & future actions. The brazing segments are particularly satisfying; brazing with gas torches & welding steel with acetylene were things I enjoyed long ago in high school metalwork that I've never done since. (I don't think schools teach much woodwork or metalwork these days.) [Attributing your videos being recommended to me due to my often watching Big Clive's tear downs.]

Your videos are like warnings for people looking at Lennox and Carrier equipment 😂

It is almost capacitive coupling. Induction coupling also exist, but if you run straight and return wire next to each over magnetic field is in balance and cancel each over.

@DEW409

Жыл бұрын

That’s what I was thinking. Phantom voltage can be caused by either capacitance or induction. However, hooking low voltage wire up to line voltage can get somebody killed. Not to mention electrocution, imagine a person on a ladder unexpectedly getting hit by line voltage could have easily fallen to the concrete floor, receiving severe injuries. I know a woman who was getting Christmas decorations out of the rafters in her garage. She fell, hit her head and died.

@denverbraughler3948

Жыл бұрын

Except that the wires aren’t twisted, they’re parallel and the square of distance separating them applies with respect to induction. As for the parasitic capacitive coupling with 120 VAC, there is no equal and opposite voltage. With 240 VAC, there is, but again, the wires aren’t twisted. So the voltage that is opposite but three times farther away cancels only one-ninth of the capacitance, leaving 88% present in the ungrounded and unused parallel conductor. Tell me, please, where I’m wrong.

Looks like someone from a smoke detector company came along after some point that the ACs were installed that had no idea how that AC worked and just wired it up...

It is called Field Vector Electrodynamics!

Chris in previous films you said your looking for a combustion anylizer am now retired I did a lot of that work on those rack burners don’t need one now on multie fuel burners it’s different yes

Love the videos!

hahahahaha "what are they doing here, they're breaking the high voltage"

Big picture gang strikes again! The phenomena you looking for is called induction, but it's probably negligible here due to low frequency of the AC voltage.

Hay brother you need some refrigeration gauges hanging up will look so good

I like those Lennox RTU's from a service standpoint. They are fairly easy to work on and get to different components. Its called induced voltage when other conductors are in close proximity to conductors that have voltage running through it. That isn't grounded. Aka phantom voltage Great video as always Chris....thanks for sharing

@willspeed4585

Жыл бұрын

My install drawings specifically state “DO NOT RUN SIGNAL AND POWER WIRING IN THE SAME CONDUIT OR RUN”. Queue the surprised Pikachu face when I make the LV installer rip them out and do it right.

Thanks!

Rofl Chris! I was waiting for you to say you couldn't help it when you were talking about the high voltage on the thermostat wires. I was saying to myself "he's gonna fix it anyway". Lol. Then you did it. It's a disease man. I totally understand. Yes, it's called induction when voltage is induced through the electromagnetic effect (no physical connection). Impedance is the ac version of resistance.

@HVACRVIDEOS

Жыл бұрын

I will discuss this on my Livestream this evening 3/20/23 @ 5:PM (pacific) over on KZread come over and check it out kzread.infovKpJKA-Y51U

Yes it's induction, and it happens when voltage is oscillating/switching. However, with insulated wires, it's not likely to induct from one wire to another as voltage, especially if both wires cycling times are the same, then there is no induction transfer. If both of those wires were tied to the secondary side of that transformer, then yes both wires are on the same cycle times on a single stage transformer. For induction to occur from one wire wrap to another, it takes a lot of wire turns running close together but not touching, otherwise the air gap is too wide and voltage is lost. To induce voltage, the field needs to be strong enough to be transferred as any real measurable voltage, which is the job of a transformer. Air gaps and amount of wire turns is everything when it comes to proper induction for any given voltage level.

8:18 so they have taken a ceiling detector and manufactured a casing for it so that it can sample the air stream from the duct.

Thats nuts that they had 240v running through that wire. I did silly things like that as a kid using speaker wire to run party bulbs and that. BTW what you were looking for is an induced voltage.

25:52 - Thanks for reminding me. I was actually wondering if you were going to get shocked from the unused t stat wires having shorted against a hot one! And you’re right: it would be induced voltage depending on how many twists per linear foot of cable.

For units over 2000CFM there's a requirement in IMC 606.2(2021) for return smoke detectors. NFPA 90A(2018) 6.4 requires supply smoke detectors over 2000CFM. Therefore, depending on what codes are adopted, or the person engineering the system doesn't look up all of the adoptions and covers themselves, you will see both.

idk why youtube isnt recommending me your videos anymore i had you manually search through my subs, anyways I came to say whats up

Induction indeed! You can also get some capacitance with long wire runs in combination of certain cable types. I work on safety PLC's with safety pulse test functions that fail when wire is ran well beyond its limitations. Probably never have to deal with high frequency signals but it's an interesting find when troubleshooting safety circuits. Interesting to see circuits in the HVAC world

Chris, just so you know most thermostat wire is rated for 300volts. Should you run 240volts on t-stat wire? NO!! That was a cheap way to do what they did. And dangerous to anyone working on the Fire Alarm system. Someone might have got seriously hurt in that detector if the stuck their hands in it thinking everything was low voltage in it. Most Fire Alarm controls are low voltage. If we need control anything for fire alarm that is over 24 volts, we tend to use relays to control the high voltage.

@throttlebottle5906

Жыл бұрын

most of it rated to 150 volts. but it's all considered class 2 wiring and should never have high current nor line voltages present.

@HVACRVIDEOS

Жыл бұрын

I will discuss this on my Livestream this evening 3/20/23 @ 5:PM (pacific) over on KZread come over and check it out kzread.infovKpJKA-Y51U

@rf159a

Жыл бұрын

@@throttlebottle5906 I worked commercial work for 35 years and we always ran thermostat wire which was rated at 300 volts. It may have been the specs of the contract that required it. That's why I said that. Sorry if there was a confusion in voltage rating.

@throttlebottle5906

Жыл бұрын

@@rf159a in commercial it may be ran in the same conduit/boxes as line voltage control circuitry, if that's the case, then it has to be building rated wiring, so the same THHN/THWN(whatever was used) to meet code and 300v or 600v depending on system voltage. same for inside the equipment, the wiring has to be coated and rated for the line voltage present and where it terminates to low voltage cabling exiting it has to be isolated into a compartment(or should be), I have seen plenty of failures there. if in standard electric boxes they need a separator/divider.

I recently found 1 where they had powered the smoke using t2 transformer then broke t1.

I would love to see that experiment, it would interesting and I suspect that there would be at least a few volts on the other wires of the stat wire but I am no expert, I don’t even work HVAC but I love these videos I feel like I have learned a lot, but I know it isn’t for me.

Discovering surprise high voltage, never a good thing. ⚡💀

@qomco

Жыл бұрын

Very true. Im a little careless with 24v, this is a good reminder

Electronics and electrical engineer here. Smoke alarm circuits should always be wired over NC (normally closed) contacts on the detectors. A smoke condition should result in the circuit going open. Reason being is that if a fire caused a smoke circuit cable to be severed, you'd get an alarm condition no matter what. If you wire across the NO contacts and expect the system to provide a closure and the cable has been severed then you get no alarm state. The other reason is that by using the NC contacts, if a detector loses power then the relay opens and you get an alarm state. If NO contacts are used and the detector loses power, you'll never get an alarm. I hope that all makes sense.

I love your videos 😂

I had a recent case of "What the fuck". A tech quit, I got his follow up repair on a lennox Air Handler/heat pump. Replacing some sequencers and limit on an electric heat kit. But when I got there, none of the low voltage for the sequencers was right. And I was just returning to work from being sick so my mind wasn't sharp. It confounded me for a while and I just decided to stop trying to figure out what happened and just rewire it according to the schematic. Turns out, on this lennox AH the w2(technically w3) and r terminals are jumped from the factory assuming you'll install an outdoor thermostat. Well whoever installed it didn't. And I'm assuming they couldn't figure out why their aux heat was constantly running. So they rewired all the sequencers in a really weird way to get around not reading the manual and just cutting the jumper like it says.

Secondary; 0:04, (not connected), 19 gauge wire, acts like a step-down power transformer, probably with low current. Like a previous comment, hope the 240 VAC side had a low amp fuse size. Those primary, (hot - connected) wires, would light up, if pinched together somewhere in their path, if having a high current flow.

I've been on job sites under high-voltage lines and they will tell you do not touch the pipe that ungrounded it can be charged and they have had worker get crap knock out them so it wouldn't be a shock if so kind voltage would be in the other unused wire

Please tell me you turned those service lights on each unit off when you left 😊

If you change the video refresh rate a bit then you should be able to find a point where the screen refreshes with the camera, so everything is visible. Might just need to go down a few hz, it looks like you're filming at 60hz, maybe your camera can do 30 or 50hz, it might be easier to read the screens then

two wires next to each other is capacitive coupling. but yes there would be something. two coils near each other is inductive coupling.

Hey mate,would love to see a video of disastrous electrical problems,with some smoke and fire,if you have anything along those lines?⚡🔥⚡

Yes, inductive coupling...but probably more an RFI problem...still that wire is so small and if there is a short with no fuse, the entire length would probably go off like a firecracker...that small wire is its own fuse...

You would have to tie two of the unused wires together on the other end in order to complete the circuit. But if you did that, you probably would measure some voltage across there.

I work with a guy who has no clue(bosses nephew). I was working on a 30 ton CRAC unit and noticed the shieve and pully were junk,so I waa on the phone ordering new parts,when I get off the phone he asks why Im replacing them! So ,I explained how they work and how to get ratios out of the adjustments etc,and it has to do with belt displacement for the target speed! He says cant you just close up the adjustable shieve and run a shorter belt! He was on his own after that comment,WTF

@jasonjohnsonHVAC

Жыл бұрын

Yo Peter....whats up my friend...hope all is well

@petersmart1999

Жыл бұрын

@@jasonjohnsonHVAC Hello Jason,been absolutely slammed at work.We had a guy retire,got one out with a hip replacement and another had hand surgery,so I been picking up the slack. Lots of long days

Yay they (YT) send new video notification for me

Yes, induction because you are inducing the magnetic field that around the wire. Wires running parallel and close to each other. Same thing applies when running cat 6 ethernet and telephone cable. Separate away from line voltage and cross perpendicular if possible.

I wish there were videos like this by elevator techs, I think that would be cool to watch too

12:25 for the discovery

Oh heck yeah bud 👍

induction considering it is twisted wire I would expect a lot of voltage being induced into the other wires but with the low current it may not be as bad as we would expect, higher currents cause greater induction

Hi, yes magnetic induction

13:40 okaly odaly

Wouldn't it be safer if the circuit needs to be open by the smoke detector? The other way, the smoke detector having to send 24v on the circuit, will not work if the cable is interrupted, and you will never know. With the other configuration if the cable is interrupted the unit will not work and thus you repair it. You could have put a 24V relay to close the contact to the unit when the smoke detector did open the connection, that way it's more failsafe.

in Washington DC area the condensate is drained to roof. looks like cali has code that roofs cannot be wet, correct?

Its curious how the internal wiring reminds me of the video game Oxygen Not Included, in the game there is a lot of automation wiring.

Chris, why did those compressors make that little chirp when they started up. I feel like I know why but you are licensed so that's why I'm asking.

We have issues with voltage leak with communicating equipment. You would have most certainly had measurable voltage leak onto the other 24v wires

I have to fight electricians and fire guys all the time about this. I don't know how many more times I have to hear "it's rated for 600v" when I point out they are using 18g for 120v circuits when our diagram specifies 12g wire minimum before I lose my mind.

Reminds me of DIY that we find in residential electrical here in the UK... with 240v run thru bell wire for lights, because 'it's smaller and neater, what do you mean the condition report is a fail?

Alright, so p1 done. I need p2

I miss those Lennox L series

I hate when i do repairs like this and tgen they go back to the original dingalings for service.

Shouldn’t the priority be the kitchen AC. The customers have a choice about being in the restaurant but the workers don’t. Plus they’re in the hottest part of the building.

240 VAC through stat wire, with insulation typically rated for 100 VAC? 🤷‍♂ That's a scary thought... 🔥 There wasn't even an attempt to use the right wire for the job. You are right, the proper terminology is "induced." You can absolutely detect measurable induced voltage on those lines if conditions are right (admittedly I'm not much help on the scientific front), but you'll also find if there is a load attached, the voltage will drop to zero because there's practically no current, any load at all will sink that induced voltage. I'd venture a guess there are quite a lot of "phantom voltages" you've never seen over the years due to resistors and capacitors in-circuit effectively canceling the effect.

I've seen them offer a dual smoke detector on the supply and return.

I find the dectecter head shorts out

Capacitive coupling between conductors. Not so much inductive unless the wires are long.

I call that "Ghost Voltage" when an unused wire is energized by a close live wire, It is the capacitance that causes the unused wire to become "Hot"

I have used sensor cables like that before, as long as it's just a switch and doesn't run any amps. One time they forgot to put a door switch on a freezer room, CBA to run a new wire but the temperature sensor cables usually have at least two unused wires. A small solenoid valve would probably be ok too, just make sure to put a tiny fuse in series.

@Tokaisho1

Жыл бұрын

Until a tech thinking it's low voltage gets electrocuted and dies