I built my house about 4 years ago and within a year both my UltimateAir DX200s stopped working and UltimateAir went out of business.  See this thread:

https://www.greenbuildingadvisor.com/question/ultimateair-contact

I’ve finally got around to trouble shooting them but need some help.  Here is what I know so far:

1) When I plug in an turn on nothing happens.  The fuses are all good and I am getting the correct AC voltages and at the obvious spots on the circuit board terminals.

2)  The manual shows that the wall controller (used to turn on the unit and set the flow rates) is connected to a terminal block in the circuit board with printing on the board showing what each terminal is for.  However my board has female RJ45 connector and there is no indication on the board what each wire is connected to.  There for I have no idea if I have connected the wall controller up correctly.

3) When I turn the boost on I get 2 out of the three motors working.  The supply and exhaust motors work when under boost.  But when the boost is off they are not working (I’m sure this is to do with the wall controller wiring).  The enthalpy wheel motor doesn’t spin at all.  I can spin the motor by hand and see the enthalpy wheel turn so the belt is good.

4) The enthalpy wheel motor is made by ebmpapst and is model number M3G055-BI and appears to be 130 VAC.  While I couldn’t find the motor on the company website I did find another fan that uses that motor:
https://img.ebmpapst.com/products/manuals/K3G200AD1102-BA-ENU.pdf

5)  When the power is on in there is a red light shown on the circuit board.

See all the attachments for excerpts from the manual and some pictures of the board.

Questions for anybody familiar with this unit or if anybody has any useful input:

Q1.  What does the red light indicate on the circuit board?
Q2.  Does anybody know how to wire the wall unit to the RJ45 circuit board?
Q3.  Does anybody have a manual for the DX200 that shows an RJ45 connector on the circuit board instead of a terminal block?  If so can you post a link to the manual or attach some pictures of the relevant data.
Q4.  I’ve heard that these circuit boards go bad.  If anybody has any suggestions on what parts of the CB go bad I am confident that I can replace specific components, I’m just not easily able to really trouble shoot the CB without a full schematic.

I’m hoping to get these units up and functional so that I can give 1 to a friend who might need it for spares for his in the future and/or 2 donate one or both of them to a building resource center.

See attached pictures.

Thanks for help.

Airfix