Control of Broan (Venmar?) HRV or ERV Info

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jeditekunum

Active Member
Thought I would share what I have learned. This data is from a Broan ERV140TE. I suspect a Broan HRV150TE has the same controls. It appears these may be the same as Venmar E15 ECM ERV and HRV and likely similar vanEE products. They are all the latest generation ventilators with energy-efficient ECM motors.
 
Remote control consists of 4 wires labeled B, G, R, Y.
 
B is ground.
Y is +12VDC.
G is control.
R is unknown at this time.
 
Control is via a resistance between G and B terminals. I've tested with a variety of resistor values:
 
4K: high
12K: high
 
18K: off
22K: off
 
33K: low
43K: low
51K: low
68K: low
80K: low
 
90K: off
 
In other words, anything between 33K-80K is low, less than 12K is high.
 
It appears that the "protocol" (resistance values) are not consistent from generation to generation or brand to brand for that matter. Another post in this forum years ago had very different results. This ventilator does not work with a Carrier Infinity system NIM so the ventilators from Carrier (also made by Venmar) are either different generation or are intentionally different for "proprietary" purposes.
 
 
I am now controlling this from a small AVR using a digital potentiometer. Using the resistance values:
 
~5.6K for high
~51K for low
~22K for off
~92K for transition*
 
* I've found that it is unreliable to go from one state directly to another. If I insert a transition level for 5 seconds before switching to a new state it seems to be rock solid.
 
I'm using a 0-100K digital pot although I'm measuring around 92K at highest setting. The one I'm using has a single byte for the resistance setting so 0-255 must be adjusted. I suspect that for any given part one would have to try a variety of settings and measure what you get.
 
This is the "control" side of my little adapter. The "driver" side is discussed in another thread.
 
It appears that this general approach could be used to translate between any incompatible ventilator and control system. One simply has to find the right resistance settings through trial and error.
 
 
Which controller for this unit have you tried reversing? From the looks of it, this unit is compatible with the VT4W (3 wire), VT6W (2 wire),  VT7W (4 wire), and VT8W (4 wire). http://www.broan.com/common/productDigitalAssethandler.ashx?id=5942bf5e-9974-43f0-931f-ff778c55cef7
 
Have you tried to see if the unit was RS-232? Could you possibly take a picture of the unit's PCB, so that we could figure out which chip is the MCU as to look up it's datasheet? The 7W and 8W transmit RH and temp data, so I'm wondering how they are doing that?
 
I abandoned full control when I gave up on getting my Carrier system to behave. I now just drive a relay with a single resistor to get the speed I want. Then ERV drives the air handler to turn on the blower.
 
I had no controller at all. I manually connected that entire list of resistors to see what it did. All those controls connect to the same places so I imagine they all work the same.
 
There is no RS232 port on the exterior of the unit. I would be extremely surprised if knowing the chip provided any useful info.
 
I never figured out what the R terminal does. Although I suspect there is no transmission of RH/temp; I think the control has those sensors and drives the ventilator appropriately. The R may provide info to the controller like freeze detection.
 
jeditekunum said:
Thought I would share what I have learned. This data is from a Broan ERV140TE. I suspect a Broan HRV150TE has the same controls. It appears these may be the same as Venmar E15 ECM ERV and HRV and likely similar vanEE products. They are all the latest generation ventilators with energy-efficient ECM motors.
 
Remote control consists of 4 wires labeled B, G, R, Y.
 
B is ground.
Y is +12VDC.
G is control.
R is unknown at this time.
 
Control is via a resistance between G and B terminals. I've tested with a variety of resistor values:
 
4K: high
12K: high
 
18K: off
22K: off
 
33K: low
43K: low
51K: low
68K: low
80K: low
 
90K: off
 
In other words, anything between 33K-80K is low, less than 12K is high.
 
It appears that the "protocol" (resistance values) are not consistent from generation to generation or brand to brand for that matter. Another post in this forum years ago had very different results. This ventilator does not work with a Carrier Infinity system NIM so the ventilators from Carrier (also made by Venmar) are either different generation or are intentionally different for "proprietary" purposes.
 
Click to expand...
Hi, maybe this can help someone if still interested!
After some investigation, the Carrier NIM uses 3 resistors on the board to control high, low and off. 22k for off, 220 for high and 4.7k for low. So logically just solder new values in their place. I used 4k for high instead of the 220, 56k for low instead of the 4.7k and 100k for off. So far my infinity thermostat operates the venmar avs i use, just like a carrier branded unit.
 
I've got a vanEE 200H HRV and was able to get high and low speed control through my automation system thanks to some of the info posted previously by others in this thread.
 
The wall control I have for the HRV has a 47K resistor on its circuit board, so I've got 2 relays connected to the "G" and "B" terminals on the 200H. One relay just closes the circuit - that turns the HRV on at high speed. The other relay has a 47K resistor in the loop - that gives me low speed. I tried using the "OC" and "OL" terminals, but those always seem to switch it on in high speed, even with the resistor in place.
 
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