Need quick fix for Intellitec EMU-2

[The Incorrigible Dirigible]

Problem: energy management unit (EMU-2, by Intellitec) has failed. The device prevents both rooftop AC units from running at the same time when plugged in to shore power, to prevent overloads.

This part is obsolete, being from a 15-year old, currently orphaned coach, and my conversations with Intellitec have not indicated that there is a comparable replacement available.

My shop's proposed solution is to rewire the whole coach for 50amp power, which is a great deal more expense than I'm willing to go to at the moment, especially as we are scheduled to leave for an Amazon workamping job in less than two weeks.

Of course, we won't be very happy with out AC or a heat pump, either. Does anyone know of a workable (preferably inexpensive) repair or replacement for a defective EMU-2?

If not, is it possible to wire a simple toggle switch, allowing manual selection of front or rear AC units? I know that this won't allow both to run at the same time, but we've never needed both at the same time. It seems like this would be the easiest and simplest solution, but I am neither an engineer nor an electrician, and so there may be some issue I'm overlooking.

Any advice is appreciated. It's extremely warm and only getting hotter...

[F&D ABQ]

Originally Posted by The Incorrigible Dirigible

Problem: energy management unit (EMU-2, by Intellitec) has failed. The device prevents both rooftop AC units from running at the same time when plugged in to shore power, to prevent overloads.

If not, is it possible to wire a simple toggle switch, allowing manual selection of front or rear AC units? I know that this won't allow both to run at the same time, but we've never needed both at the same time. It seems like this would be the easiest and simplest solution, but I am neither an engineer nor an electrician, and so there may be some issue I'm overlooking.

Any advice is appreciated. It's extremely warm and only getting hotter...

I don't know why you couldn't use ordinary house-wiring switches, with adequate rating of course. Here's a tutorial on using multiple switches to control multiple loads: Multiple lights, multiple switches. But what's the benefit over just using one A/C?

In my (50-amp) coach, the front A/C is separately powered by the generator unless actually plugged into 50A shore power. On 30 A shore power, only the rear A/C works. To obtain an approximation of that, you'd wire just the front A/C into the generator (which has its own circuit breaker for that load on my unit) and wire the rear A/C into the normal house wiring. Obviously in that case you'd only have the use of the front A/C when on generator.

[The Incorrigible Dirigible]

Originally Posted by F&D ABQ

But what's the benefit over just using one A/C?

I don't have a problem using just one A/C unit--in fact, we've never really needed both to run. The problem is that when the EMU-2 fails, it won't allow either A/C unit to run on shore power!

[Gary RVRoamer]

It should be easy enough to remove both a/c's circuits from the EMU's control. If it is like the newer versions of the EM system, it just has a couple relays that it can open or close to prevent the a/c from running. Disconnect the wires from the relays and splice them togther, or if long enough, connect them direct to the circuit breakers for the two a/c's.

You can find the EMU2 Service Manual here - should tell you what you need to know:

Service Manuals