Need some EMS help

[rvmaybe]

Front AC is randomly cycling off for a few seconds before coming back on. Coleman tech thinks that the EMS is cutting power to the AC, then resorting it.

I can't find any documentation on how the ems system is wired or how it functions on this coach.

I have the all electric 2007 Affinity so there is a relay for the AC on inverter function but I don't see any way for the Silverleaf or Intelletec systems to interrupt power to the front AC.

I would appreciate any insight you might have.

Thanks.

[Old-Biscuit]

Are you plugged into 50A Shore Power?

Does the A/C Fan also stop or just the A/C compressor?

Do you have just ONE thermostat ?

[okcnewbie]

When plugged into 50amp or using gen there shouldn't be any shedding going on normally.

Download the intellitec EMS manual. I would assume that your front AC is one of the items managed by the EMS.

The tech may be right. It will take more info/readings to find out. Heck, I'm impressed that he even knows about the EMS

[Smitty77]

Possible starting control board failure is occurring...

Our 07 Magna's receipts. Indicate replacement of two control boards (AC 1 and AC 2), with the noted problem being 'Sporadic start up...'. (Which surprised me, as circuit boards are usually sudden failure, I had expected to see the repair being a capacitor...)

Smitty

[rvmaybe]

All:

This problem occurs on 50amp shore power and on the generator.

One thermostat.

The fan and the compressor stop, the fan comes back on almost immediately. It may run the fan for a bit or it may start cycling the fan. If the fan stays on the compressor might come back on after a delay. All symptoms seem to be variable. On this model the fan is not wired to the pressure switch, it is controlled by the control box in the plenum.

I can't find any mention of an Intellitec EMS manual for this coach.

So far I have replaced the thermostat, all 3 control boards, the temperature sensor for the front AC, run/start caps in all three units, tightened all spade connectors. No florescent lights. Installed a power filter for the thermostat.

There are times when the AC will run normally for a day or two so this seems like a power or control signal issue. Pulling the fuse on the thermostat seems to solve the problem sometimes but it always comes back.

Thanks for your thoughts.

[jacwjames]

Do you have a load meter showing amp draw.

Here's a link to a manual, it is an earlier version but should give you an idea on what to look for and determine if this is the system you have. https://intellitec.com/wp-content/up...-00894-000.pdf
There are other manufacturers of this type of system so the first step is trying to figure out what you have.

[rvmaybe]

The Silverleaf system shows amp draw, about 12 amps for the front AC.

Talked to Silverleaf (great technical support) and they said that the Silverleaf system of 2007 vintage only control items on the network and so the Silverleaf system does not manage any electrical loads.

There does not appear to be an Intellitec EMS panel anywhere that I can find. The owners manual does not mention energy management at all.

The Intellitec system does manage the relay that switches the front AC from coach AC power to inverter AC power. I think I'll disconnect the control line from that relay and see if that stabilizes the AC. Another option would be some kind of power monitor on the AC feed to that AC unit to see if the power is actually dropping out. Any ideas what I might use for that?

[jacwjames]

I installed a Progressive Surge Protector HW50C. This monitors the quality of the power for High/Low Voltage, Correct wiring for neutral and ground. It comes with one monitor but I bought a second one. One I have mounted in an outside compartment so I can watch when I plug in. The display will go through a check and will not pass power until it determines all is OK. Once it connects I can hear the transfer switch engage. I then flip a switch to send the display signal inside. I can then monitor the voltage and amperage on L1 & L2. Since each of my AC units are on a different leg I can see the amp draw.



I went for ~5 years without this and then a lightening strike hit our house. Took out a TV in the house but also caused damage to the coach. I installed the HW50C right after that. It's saved me from low voltage and reversed polarity several times.

[hoosierrun]

Perhaps your compressor starting capacitor is on its way out. When that happens, the fan will come on, the compressor will attempt to start, if compressor does not start, there is a momentary locked condition which draws big amps and often operates a thermal cutoff to protect burn out. That might or might not shut the fan off. I would guess with the generator the fan might continue running, but with shore power, the EMS might detect an overload and cut power. That is one possibility, but if it is an older unit, I would change the compressor start capacitor. They are not that expensive in the big picture, and your compressor can only take being locked so many times before it burns up.

[RCattell]

Hi Rvmaybe,

Our 2007 Magna was doing the exact same thing.

The front AC is daisy chained to the mid AC as far as the DC thermostat control is concerned.

Our tech found a loose wire on the DC circuits on the mid AC that was causing the front AC to do the exact same thing as yours.

We replaced all caps on the front AC and we have a new thermostat that is not installed yet. Turned out to be a loose wire.

Let us know how it works out. Cheers.

[turbine52]

Have you thought about switching the leads in AC box from unit 1 to unit 2 and vice versa to see if it follows. Just a thought and I think fairly easy.

[BrianGlenn]

The intellitec load shed relays are in the AC distribution panel in my 2007 Allure. They are a known failure point. The AC load wire will route from the breaker to the load shed relay and then off to the AC.

I am pointing to one of the relays.

[wfalch]

So this is could be why all of a sudden the GEN light comes on?

[jwlce]

I have the same issue on my 07 Affinity I replaced all the caps in all the a/c units and no change on this issue. I do know that the a/c system is touchy. I found a radio shack 12v supply zip tied to the wall but disconnected behind the thermostat panel. This was Factory installed in that there was a 110v outlet back there to power the 12 supply. In speaking to an ex CC employee there was an issue with electrical noise apparently from the florescent lighting that would cause the A/C to units to drop out. There is a transformer and capacitor "loosely" wired into the circuit that I guess was the final fix. I have just gotten to ignore the start stop.