Community Forums

ballkiddy · 09-26-2022, 01:08 PM

I have a 2002 Expedition, 5.9 cummins with a 7500 ONAN generator, 30amp rig with two Coleman Mach 3 rooftop AC's. Rear AC is less than five years old and i just replaced front AC last year. I noticed that prior to replacement of the front AC, that it would "shed" quite a bit somedays. New unit does the same thing. In sheds on shore power, it sheds on Gen power, it sheds when it is running all by itself, it sheds when running with rear ac. Sometimes it may go a few hours without shedding, but this past weekend, it shed every five minutes i bet. Just off and on all night. I'm currently checking connections in breaker panel, going to replace main/front AC breaker. (i thought it may be causing to much drag and tripping the donut amp sensor) could the donut amp sensor be bad? could my ECC be bad? i shut power off to it for a minute to reset, same result. could my EMS be causing this? I'm at a loss but very frustrating. The rear runs fine, all night and all day. If something needs to shed, the rear would shed first but it never sheds. I know this belongs somewhere else probably but im a rookie at message boards....sorry.

un4givn85 · 09-26-2022, 02:03 PM

do you have any way to measure amp draw? Like a surge protector or Victron equipment.
the Intellitec system uses amp draw and calculations to determine when to shed, there could be something related to the front AC causing it draw more than is should be.

Bobby Dowdle · 09-27-2022, 06:37 AM

Bypass the ems board in the breaker panel. Move the wire hot lead from the relay to another breaker and test functions. Be careful not to shock yourself. You really need to take this to a shop.

Bigd9 · 09-27-2022, 07:07 AM

Could you describe exactly what you mean by shedding please? Does the entire air conditioner go off, or just the compressor, but the fan is still running?

I would try and remove the 12 volt fuse for the EMS system, wait a few minutes and then plug that fuse back in. I know on my coach every once in a while the EMS goes silly. In my 2006 Discovery coach, the fuse is back on the bed frame inside the fuse box.

Also, just a shot in the dark, but in my coach, I found the air conditioner control box that is mounted up in the ceiling on the air conditioner had a cord with plug that was stuffed inside a chaseway or cavity in the ceiling. Moisture had gotten to the plug and several wires had corroded off. (see picture)

Bigd9 · 09-27-2022, 07:17 AM

Forgot to mention, I think the EMS can be programed to shed different items first. So it could be someone programed it to shed the front first.

Assuming your coach has a EMS with a amp readout, what amp readings are you getting with the front unit running, vs rear unit running vs both running? How close to the 30 amp maximum are you getting before it sheds?

un4givn85 · 09-27-2022, 08:05 AM

Being a 2002, it is likely the Intellitec system that doesn't have a readout.

ballkiddy · 09-27-2022, 08:43 AM

when it sheds, it just shuts off the compressor to the front ac for two minutes, then kicks right back on and runs for five minutes maybe, then kicks off for two. I don't have an AMP draw read out anywhere on the coach, it is an Intellitec system. I think I may have found the problem. I changed the breaker out yesterday (the 30 amp main and 20 amp front ac combo breaker) and it ran fine for over thirty minutes. I'm going to mess with it some more today after work. How can i test amp draw at the breaker box?

un4givn85 · 09-27-2022, 08:48 AM

sounds like you may have had a bad breaker.
without throwing some money at the problem via a clamp meter or one of Waiter's new Intellitec replacements, no good way to read the amp draw.

MarvinG · 09-27-2022, 09:47 AM

If the problem persists now that you’ve changed the breakers you really do need to buy or borrow an AC clamp meter. They don’t cost that much in the big picture. Then you clamp it around the wire at the breaker and get an immediate readout of amps drawn. Otherwise, from here on out, you are chasing a phantom without any data to diagnose with. You’ll also want to measure voltage at the breaker at a minimum to see what voltage you have both with AC fully engaged and with compressor shedding.

Bigd9 · 09-27-2022, 11:06 AM

Quote:

Originally Posted by MarvinG

If the problem persists now that you’ve changed the breakers you really do need to buy or borrow an AC clamp meter. They don’t cost that much in the big picture. Then you clamp it around the wire at the breaker and get an immediate readout of amps drawn. Otherwise, from here on out, you are chasing a phantom without any data to diagnose with. You’ll also want to measure voltage at the breaker at a minimum to see what voltage you have both with AC fully engaged and with compressor shedding.

VolDawg · 09-27-2022, 09:15 PM

Read your owners manual paperwork on the Intellitec. There is a bypass switch built in that you can use to test the system. You may simply have a faulty Intellitec module.

I recently had issues with mine shedding at odd times. I had a backup module that I installed and resolved the issue. The module can be replaced or rebuilt. There is an upgrade that completely replaces the Intellitec called Waiter ECC. I've talked to a few people who have made this upgrade with great success.

happyseany · 10-04-2022, 03:20 PM

I BET I CAN SOLVE YOUR PROBLEM!!!! I HAD SAME ISSUE AND SOLVED FOR MANY PEOPLE!! First question.. do you have Fluorescent ceiling lights? Thin-Lite or other brand?

Try turning off ALL ceiling and/or fluorescent light in RV. ALL. Then run your A/C like normal. Tell me if the Intellitec Thermostats "SHEDS" anymore.

Bet it won't.. after this test,...reply your findings and I'll "geek-out" with you and tell you why its happening!

2cyber71 · 10-04-2022, 03:24 PM

If I have 2 ACs running on a hot day and a third starts, it sheds one of the two for a few minutes, they they all run good. It’s the start amperage surge.
I can see one line pop over 52 amps and we get a shed for about 3-5 minutes.
Turn on a microwave and you will shed.