Automating ERV with HAI OP2 and Omnistat2

D

DIYHO

Member
I have a Broan GSEH3K ERV ( http://www.broan.com/products/product/gseh3k270-cfm-hepa-filtration-fresh-air-ventilation-with-energy-recovery-79fcc0b1-c9d1-4e44-9c80-997aa84a3116 ) that I would like to automate with the HAI OP2. The plan is the use the ERV together with the HAI omnistat, temp/hum sensors (internal and external) and the HVAC to not only ventilate the house but also to cool the house during cooling months. The return of the ERV is tied into the HVAC return so I can use the HVAC to circulate the air.

The ERV has 3 modes, normal venting, high venting, and recirculation, all modes I want to control. I have the ERV remote (ACCGSC3) installed essentially right next the OP2 with a set of leads from all of the terminals to hook into the OP2 in addition to the control wire to the unit itself. I am uncertain how/where I should hook these leads up, switched outputs or relays?

When using the ERV to cool the house I will also need to temporarily disable the air conditioning and turn on the HVAC fan which will obviously require some custom programming.

I did a search for automating ERV's but came up with essentially nothing. Has anyone done anything like this?
 
You should be able to control it with relays connected to the OPII. You have to buy these relays separately, but you can connect 8 of these (I think) up to a panel, and more with expansion. The HAI relays can control an amp or two which should be fine for what you need. Use an Omnistat connected to your HVAC, and you should be able to get all the info you need to control it. One thing that maybe has been fixed by now, maybe with the newer Omnistats, but at least mine doesn't send back info on if the AC or heating is actually running. I had to install two small relays on my Omnistat to send this information back. I have two HVAC units and needed to know when the AC was running on each so i could turn off the other while peak electric rates were on. Not having both on at once during certain times keeps my peak charges lower.
 
Update on this.

I have determined the above broan ERV appears to change the mode of operation by varying the voltage to the unit from the remote. By hooking up the remotes hot and common to the relay board I am able to turn the unit on and off, but only on the mode I have the remote switch set to.

For now I have the system automatically venting on low based on certain conditions, however I would still like to get automated access to the other modes without having to use the remotes switch. Anyone have any ideas on how to go about this? I am thinking I might need to split the hot and common to three different relays and put some type of resistor in line?

I was also able to automate the HVAC, temp sensors and my ceiling fans to work in conjuction with the ERV per my above plans without having to do anything special for HVAC control, after much hair pulling due to the most frustrating HAI programming language and interface.

With respect to the HAI programming. The HAI programming language has got to be the most illogical, unintuitive, inefficient programming method that I have ever used, and I am versed in multiple different programming languages. The amount of redundant programming needed just to execute a simple else condition is rediculous, and that is just one hair pulling, head beating example. If anyone at HAI development is reading this .... where is the support for your standard if -> then -> else?
 
I thought Else statements were added in V3.0 and above. Not sure though. What HAI firmware version are you using?
 
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