Onan Energy Command 30 Install Question

[mikeyj67]

I have wired everything in my install except the run request wire for the air conditioner. How do I wire this with a Duo Therm digital thermostat??? Any help would be greatly appreciated.

[mikeyj67]

I have wired everything in my install except the run request wire for the air conditioner. How do I wire this with a Duo Therm digital thermostat??? Any help would be greatly appreciated.

[Rex]

Well, you are a bit ahead of me. I have not started the installation yet as I am trying to determine just what you ask. I have all the other wiring identified already. Looking at the wiring information in the Duo-Therm manual, it appears run request wire for the air conditioner must come from the front air conditioner rather than the thermostat itself. The only wiring to the thermostat I the 4-wire telephone like cable. The thermostat is powered via this cable as far as I have been able to determine thus far, but that could be wrong. If you get it figured out, please post your solution here, and I will do the same. Or contact me rbdtanasi on yahoo if you wish to communicate privately. Where did you place the unit in your coach?

[dgerstel]

I don't know about the Onan Energy Command 30 control, but in the alpines there is a separate AGS module that works in conjunction with the generator control panel. Try looking up that info at the Onan website.

Dale

[mikeyj67]

I placed it in the cabinet with the thermostat. I replaced the original generator panel with the energy command unit....since it is the same size, has an hour meter, and obviously many more features over the stock panel. I have had it installed for several months now and it works great. If I could only figure out the AC problem I would be in fat city. I contacted Duo Therm today and they would not tell me what to hook into in the AC unit itself...claiming liability issues, which I think is a load of B.S. I tried metering out the wires in the AC, but did not see anything on the meter that would indicate a run request.

[RV Wizard]

mikeyj67, you should be looking for a 12 volt signal for the cool/on from the T'stat. You will need the schematic for the control board for the air conditioner. From the thermostat you will need to find what point you can tap into where 12 volts is supplied for cool on before the time delay relay on the control board. This will allow the genterator to get started and warm up before the compressor relay closes.

[Cruzer]

I went through this with my '04 Bus when I installed an AGS module. The problem is that the Dometic system doesn't have a 12 volt thermostat output, nor do the A/C units.

Instead, each A/C unit communicates with the thermostat via a cat5 data cable. Each A/C unit has a control board inside that has DIP switches that are set to give each unit a unique identity, or zone nbr. In addition this board has breakouts for the furnace zones.

Dometic does make an extra communications module that is designed to be used with an AGS. I actually have one of these left over on my workbench because I bought two of them by mistake. This module has a board with DIP switches that get set to the AGS position. It also has a cat5 port to connect it to the data bus as well as a 12 volt breakout terminal connector to feed the AGS contacts.

Each Dometic A/C unit has two whip cords with female RJ45 jacks on it. On my '04 Bus the thermostat connected to the front A/C unit on one jack and the second jack daisy chained over to the rear A/C unit. The extra jack on the rear A/C unit was where I connected a cat5 cable to connect to my AGS interface, which I chose to mount in a basement compartment. From there I ran a pair of low voltage wires to the AGS.

In addition to the digital/analog breakout box module you also need a Dometic # 3109311.005 wire harness kit, which includes the wiring harness necessary to connect to the AGS. The installation instructions are Dometic # 3109312.011

[mikeyj67]

Cruzer..thanks for the great info. I am assuming that even though the module hooks to the second AC, that you can still tell the system to use either the front AC, rear AC or both. Also, since you have an extra module, would you be willing to sell it? Thanks again

[Cruzer]

I've responded to that via email rather than on the forum.

[Rex]

Been doing more research with the drawings for the AC units and the Comfort Control thermostat. It appears there is a dip switch that can be set in the AC unit. At least there is one there that is labeled Gen Start. The installation instructions for the AC say to leave it in the off position. I will call Tech Support tomorrow and see if they will tell me what that switch does in the ON position.

The thermostat is digital so there is no way to pick up a run request from it. I'll keep working on this, and there should be a simple way to do this.

Cruzer, thanks for the info and Dometic numbers. Please provide the number for the Communications module you spoke of.

[Cruzer]

The control module in the A/C unit is a univbersal module. The same module can be used as an AGS interface but you can't flip DIP switch #8 to make it an AGS interface while allowing it to be an air conditioner at the same time. So, you need the extra module to enable AGS capability from the thermostat.

The control module is # 3109226.005 but you also need a # 3308013.006 communications cable to connect it to the data bus and also a #3109311.005 wiring harness kit (or maybe just a #3109546.006 wire harness pigtail) to finish the job.

I put my control module in a basement compartment and ran the communications cable up through the closet and through the A/C duct to get to my rear A/C unit, where I tapped into the data bus. I then ran a pair of 12 volt wires from the new controller in the basement up to my AGS on the '04 Bus. When it was all done I had to reflash the thermostat to allow it to detect the new device. It then shows up as an extra "Zone" (device, actually) on the thermostat. The flashing is easy just by holding down the right buttons when powering it up.

My '07 Bus has the EC-30 but it has RV Comfort A/C units so I don't have to deal with the digital interface that the Dometics used any more.

[Rex]

Thanks a lot Cruzer. That is a big help.