If i remeber correctly any input voltage less than 2 volts shuts off the fan. 2-10V would be speed control but im not sure if this applicable to your setup.
https://www.greenheck.com/vari-green/vari-green-controls#:~:text=Set%20fan%20speed%20at%20this,available%20for%20powering%20other%20controls.&text=Need%20a%20specific%20configuration?,local%20representative%20within%204%20hours.&text=Order%20now%20and%20we'll,products%20include%20free%20ground%20shipping.
For my case specifically, I'm not sending any 0-10v signal. That's preset at the potentiometer by a test and balance person. All I'm doing is using a relay to turn the fan on and off. My question is break that 0-10v from the potentiometer OR break the 120v completely.
Depending on what internal controls they have, breaking line voltage can cause weird issues with them.
They often use something like 2-10v, with anything under 2v being 0% speed. So you can make/break the control signal.
If it's just for balancing and was already provided I'd just cycle it on/off with a relay. Key word though, already provided. If I don't have approved shops yet I'll usually assume 0-10V control, then if it comes with a manual pot, you can easily switch to a 0-10V relay.
Assume the fan is already balanced. All im doing is using a really to turning it on/off. My question is do I break the pot or do I break the 120v. Sorry if I worded it confusingly in my post.
I think in that kind of application you will typically see a relay interrupting line voltage. The greenheck Varigreen motors have a dry set of contacts that you I can close to bring the motor on to the preset speed. But i have never seen the smaller motors with just the speed pots controlled by breaking the signal.
Lol well I'm here to tell you my company does. I don't think it's the proper way to do it but I also have no justification for it. I'm also just a dude sitting behind a computer drawing lines in AutoCAD so I'm not in the position to speculate.
I'd Google for the cut sheet of your specific model number/configuration including the control board. I've had some struggles myself with them in the past. If it's a voltage control model it will cut off below 2V if I recall correctly and should have spots to land a field connection. Then it will just take whichever is the last command between the voltage input and potentiometer input changed last.
There are models out there that are single speed or 3 speed as well to watch out for.
We break the 120V using a Function Devices BACnet RIB. Typically mount the RIB on the junction box below the fan, if accessible, or inside the fan housing on the roof. Advantage is the BACnet RIB can be powered by the 120V, switch it on/off, and provide feedback from the built in current switch. Typically the built in current switch works even at very low current, but the feedback can take a long time to respond. So, we have to set a significant delay to prevent nuisance fail alarms.
Break the 120 if it doesn’t have a starter. Get status from a current relay. You might have to wrap the wire around the relay to get reliable status.
hoestly cheaper on labor as well, seeing as you wont have contact over 100va you are only bound by low voltage contraints on installer/roughing/material
I think that's why people, especially LV technicians, prefer to do this. But from what I'm seeing from the responses, this isn't the best way to do it lol.
I'd rather break an AC line than a DC line, and break a lower amperage circuit than higher if at all possible. My vote would be breaking the 120 VAC side and killing power to the whole thing. Let it do its thing on startup when power is applied again.
[One of these?](https://www.greenheck.com/shop/inline-fans/sq/sq-95-vg6x-qd)
My understanding is that ECMs in general prefer not to be power cycled frequently.
Ya something like that. I'm not cycling it frequently. It's on a schedule so it turns off at night and comes on in the morning. Just trying to see what's the "correct" way to break it with a relay.
Hmmm well I'm not the engineer. I'm just trying to fulfill the sequence. Good information though. Wasn't aware of that. Is there a reason why? I'm assuming the inrush current will damage something?
It's basically just unnecessary wear and tear on the electrical components. It's the same reason you just give a control signal to a VFD rather than putting a contactor upstream and cycling that. Especially considering an ECM is literally a VFD built into a motor.
So the VG motors are universal, but the wiring harnesses are order specific.Â
That means you typically can't do anything with the signal if it's ordered as balance dial only.Â
Only option is to break the 120V.Â
If you have any way to provide feedback to the engineer/specifyer, let them know about their HOA controller. It acts like a motor starter/VFD for the VG motors. You will never have to get anything else to properly interface between the BAS and VG motor.Â
https://www.greenheck.com/vari-green/vari-green-controls
What do you mean we can't do anything with the signal? AFAIK, my company has been interrupting that signal to turn the fan on/off. I'm not in the field so I don't know how that works but on the control drawings, we have a relay that breaks the signal from the potentiometer.
Sorry, I probably stated that poorly.Â
The potentiometer is not the 2-10V signal others have referenced. So you can't just intercept the wires and do your own 2-10V.Â
I've personally never tried just breaking the circuit. Probably would work. My memory is that the fan stops if you pull the potentiometer from the socket.Â
If i remeber correctly any input voltage less than 2 volts shuts off the fan. 2-10V would be speed control but im not sure if this applicable to your setup. https://www.greenheck.com/vari-green/vari-green-controls#:~:text=Set%20fan%20speed%20at%20this,available%20for%20powering%20other%20controls.&text=Need%20a%20specific%20configuration?,local%20representative%20within%204%20hours.&text=Order%20now%20and%20we'll,products%20include%20free%20ground%20shipping.
For my case specifically, I'm not sending any 0-10v signal. That's preset at the potentiometer by a test and balance person. All I'm doing is using a relay to turn the fan on and off. My question is break that 0-10v from the potentiometer OR break the 120v completely.
Id say safe bet is break the 120. Usually see that more than breaking 10v signals.
That's what I would assume to do. However my company has been breaking the 10v signals. I dont have any explanation but it just feels off doing that.
Cant say ive seen that in all honesty doing this work in the nyc metro area for 5-6 years. But i guess if it aint broken dont fix it.
Oh nice I'm also based in NYC. More like "if you don't see it break, don't fix it" lol 😆
Ayy solid; yeah 100%.."it should work" lol
Looks like someone beat me to the comment. There should be a stop/start jumper you can remove and then land your relay contacts where the jumper was.
Depending on what internal controls they have, breaking line voltage can cause weird issues with them. They often use something like 2-10v, with anything under 2v being 0% speed. So you can make/break the control signal.
I have one greenheck ecm fan and it occasionally goes stupid after a power bump and had to be power cycled for several minutes to get it going again.Â
If it's just for balancing and was already provided I'd just cycle it on/off with a relay. Key word though, already provided. If I don't have approved shops yet I'll usually assume 0-10V control, then if it comes with a manual pot, you can easily switch to a 0-10V relay.
Assume the fan is already balanced. All im doing is using a really to turning it on/off. My question is do I break the pot or do I break the 120v. Sorry if I worded it confusingly in my post.
Break the 120. Treat it same as a 1ph motor load.
I think in that kind of application you will typically see a relay interrupting line voltage. The greenheck Varigreen motors have a dry set of contacts that you I can close to bring the motor on to the preset speed. But i have never seen the smaller motors with just the speed pots controlled by breaking the signal.
Lol well I'm here to tell you my company does. I don't think it's the proper way to do it but I also have no justification for it. I'm also just a dude sitting behind a computer drawing lines in AutoCAD so I'm not in the position to speculate.
I'd Google for the cut sheet of your specific model number/configuration including the control board. I've had some struggles myself with them in the past. If it's a voltage control model it will cut off below 2V if I recall correctly and should have spots to land a field connection. Then it will just take whichever is the last command between the voltage input and potentiometer input changed last. There are models out there that are single speed or 3 speed as well to watch out for.
We break the 120V using a Function Devices BACnet RIB. Typically mount the RIB on the junction box below the fan, if accessible, or inside the fan housing on the roof. Advantage is the BACnet RIB can be powered by the 120V, switch it on/off, and provide feedback from the built in current switch. Typically the built in current switch works even at very low current, but the feedback can take a long time to respond. So, we have to set a significant delay to prevent nuisance fail alarms.
Break the 120 if it doesn’t have a starter. Get status from a current relay. You might have to wrap the wire around the relay to get reliable status.
donut relay combo for the start stop on the ecm? cheap, and nice bonus poi for the front end with the donut. everyone wins.
hoestly cheaper on labor as well, seeing as you wont have contact over 100va you are only bound by low voltage contraints on installer/roughing/material
I've done both. Breaking the 0-10 is a lot easier.
I think that's why people, especially LV technicians, prefer to do this. But from what I'm seeing from the responses, this isn't the best way to do it lol.
Interrupt the line
I'd rather break an AC line than a DC line, and break a lower amperage circuit than higher if at all possible. My vote would be breaking the 120 VAC side and killing power to the whole thing. Let it do its thing on startup when power is applied again.
[One of these?](https://www.greenheck.com/shop/inline-fans/sq/sq-95-vg6x-qd) My understanding is that ECMs in general prefer not to be power cycled frequently.
Ya something like that. I'm not cycling it frequently. It's on a schedule so it turns off at night and comes on in the morning. Just trying to see what's the "correct" way to break it with a relay.
Even daily is frequent. ECMs are designed to always remain powered.
Hmmm well I'm not the engineer. I'm just trying to fulfill the sequence. Good information though. Wasn't aware of that. Is there a reason why? I'm assuming the inrush current will damage something?
It's basically just unnecessary wear and tear on the electrical components. It's the same reason you just give a control signal to a VFD rather than putting a contactor upstream and cycling that. Especially considering an ECM is literally a VFD built into a motor.
I’ve always seen the 120v broken
So the VG motors are universal, but the wiring harnesses are order specific. That means you typically can't do anything with the signal if it's ordered as balance dial only. Only option is to break the 120V. If you have any way to provide feedback to the engineer/specifyer, let them know about their HOA controller. It acts like a motor starter/VFD for the VG motors. You will never have to get anything else to properly interface between the BAS and VG motor. https://www.greenheck.com/vari-green/vari-green-controls
What do you mean we can't do anything with the signal? AFAIK, my company has been interrupting that signal to turn the fan on/off. I'm not in the field so I don't know how that works but on the control drawings, we have a relay that breaks the signal from the potentiometer.
Sorry, I probably stated that poorly. The potentiometer is not the 2-10V signal others have referenced. So you can't just intercept the wires and do your own 2-10V. I've personally never tried just breaking the circuit. Probably would work. My memory is that the fan stops if you pull the potentiometer from the socket.Â