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Marathon Transfer Switch Issues
For those with my vintage Marathon Coach (and possibly other brands). I began having trouble a few months ago with my transfer to shore power. First it would take up to 10 minutes to activate the change over. Then a low pitched buzz whenever on shore power. Next came a loud claxon sound when switching over to shore sometimes with flashing inverter etc. Eventually when this happened I had to hit the electrical panel to get the change over. Took it to Jeff’s and I could not reproduce the issue of course.
Now I’m on an extended trip and it starts acting up. Since I was stopping at Marathon I added it to the list. The panel comes off and several of the relays are discolored from heat. Replace them. Told I need new inverters (even though they work fine on the gen and when the shore power finally kicks in). This makes no sense to me since the problem occurs before power gets to the inverters. But I can’t reproduce the issue so it must have been the relays – right? Problem solved. I take the bus for a test drive and to get fuel. As my usual practice I start the gen and crank up everything to give it a good load. Get back to Marathon, hook up the power and wait and wait for change over. Claxon sound again with almost no change over. I hit the panel three times hard to get shore power change over. In the morning back to the shop at Marathon. Can’t reproduce it – really? Again I’m told inverters.
Then I suggest we run the generator and see what happens with the change over. Gen runs for 5 minutes. Turn it off plug in. 10 minutes go by then a loud claxon sound with flashing inverters lights etc. Finally! After some meter work here is what we found that is important for any coach wired like mine.
There is a small change over sensor that activates the change over main relay. The way it works is when on the gen it heats an internal metal element that moves off of the internal contact causing the shore relay to open and turn off of shore power and on to the priority power source – the gen. When you shut the gen off and switch to shore the heat goes of and very quickly the element returns to it contact completes the circuit and the shore power relay closes and the shore is connected. The little element in this little POS switch was bad. Not only that, I was told they no longer make that switch because it would melt and had been reported to catch on fire. There is a work around with three robust components that solved the problem. The wallet biopsy wasn’t too bad since they realized they had done a fair amount of unneeded work.
Moral to the story: I didn’t need 5-6000 worth of inverters. Make sure what you are being told makes sense. I didn’t know much about the main electrical box on the bus but I did know the inverters can’t be the problem when the issue occurs before they are even energized.
Sorry for the long post but hope to save someone else misery and $$$.
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11 Replies
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Good catch, sometimes mechanics get tunnel vision and stop not listening to owner ,easy to throw parts at it.Glad you stuck to the real problem.
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What is surprising with Chris’s problem, Marathon couldn’t figure out the problem was the transfer and had nothing to do with the inverters. Chris knew what was going on and common sense pointed to the transfer, not inverters. If he wouldn’t have been insistent, staying with the bus and being involved, he would have received a bill for new inverters and the transfer switch, likely in excess of 10K. Makes ya wonder…
1984 96" with 8V92TA
(remodeled Liberty Coach)
Greenwood, MO -
A transfer switch is just a transfers switch, it takes power from shore or gen,Transfers to the bus, When the inverters receive the AC volts via shore or gen they charge the batteries and when there is no AC volts it makes 120v. Any honest RV tech should know that. If it is a 25 year old bus or a 2 year old bus the transfer switch does the same thing, There might have more bells and whistles like low and high volt cut offs surge protectors. That’s sad when a shop doesn’t know or just trying take advantage of someone. Good job Chris for not letting them do that to you.
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Inverters are repairable also, I use to send inverters down to a small shop in southern Ca Bio Benefit Energy. I got to know the Owner and his son over the phone,never met them but both were very honest and knew what they were were doing, Quite a few times I sent inverters to them for repair and instead of replacing them for big bucks they would repair them for little bucks. They said most of the time it is the contacts in the inverter causing the problem, And most of the time it was caused by electric heaters brought in by the owner. Electric heaters are high amps. They said electric heaters are hell on inverters, even know your not inverting the heater most receptacles in coach run through the inverter contacts. In my bus I keep a Dyson Heater so I installed a 120v receptacle straight to breaker panel not through inverter, It has 2 toe kick heaters in bus and Royale did not run them through the inverters. Because that reason.
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You sure it happened like that Chris?
You go up there for a new seat and want a problem fixed that another shop couldn’t fix either. You have them chasing a ghost because you can’t replicate the problem and have the other shop in your ear while Marathon is working on your coach.
Trust me they don’t need to shove inverters down your throat. Now your coach is fixed and you bad mouth them and tell all to watch your wallet.
Your whole post is bullshit.
Later,
bv
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Which Marathon facility was this?
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The point of my post was not to trash Marathon. If it came off that way, that was not my intent. I was satisfied with my service and pretty much the price. Terry at Marathon, once I figured out when the issue happens, figured out where the problem was located. Yes they told me first it was the inverters but did not insist on “selling them.” New inverters would have been a lot of dollars and would not have solved the issue. With my insistence they did keep working with me to finally figure it out. The relay replacements done at first were necessary even though they didn’t solve the problem. They were discolored and had obviously been subjected to heat issues probably from the failing component.
My point was to let others know of a difficult to ferret out issue that occurred due to a failed part that was not obvious to anyone (including Marathon) and was hard to reproduce. Don’t accept, from anyone, a quick diagnosis that doesn’t necessarily make sense (the other “shop in my ear” had told me nothing was wrong – so not perfection there either). Also this component, as pointed out by Marathon is not made anymore due to safety and failure issues. Marathon did not “make” the component and I never indicated they did.
The owner has lived with an issue and has much to offer. I have wasted a lot of money through the years on incorrect diagnoses of many problem at many places by dropping the bus off and waiting for the bill. No missed diagnoses were intentional as far as I know. Many were from relatively superficial quick evaluations. And finally I didn’t just show up just to have seats on short notice. I scheduled three days at Marathon to deal with a list of issues. I scheduled it 6 months ago. The seats took less than 8 hours of those three days.
So with that I am done. If the info helps someone, great. If not then it’s worth what you paid for it.
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
Coburg Larry.
Later
bv
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Thanks Bernie, doesn’t sound like the way that shop is run. Maybe new people?
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CHRIS. i recently had an issue with the heater relay. i contacted marathon tech for some info on the problem. was told i needed to take my coach to them for a full upgrade to the current system they have. i replaced the relay from mcmaster carr. all has been good. works as should. took me a few days. not bashing. just not happy with the support i though was going to be when i searched out a marathon.
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I had virtually the same symptoms a few years ago…. took a long time to switch over… lots of clicking and flickering. I could hear the clicking in the pass through bay. Took it to marathon in coburg and the tech figured it out pretty quickly… and some sort of relay later… problem gone.
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