Help: Lost portion of 120VAC

Wayne M · 04-10-2021, 10:15 PM

MH is parked in the driveway. PT-50X states all ils well. Air conditioner works but 120VAC to microwave, dishwasher and refrigerator is not existent. Turned on generator, same thing. Inverter when turned on does provide 120 to those items.

I"m stumped!!

akeagle · 04-10-2021, 11:08 PM

Quote:

Originally Posted by Wayne M

MH is parked in the driveway. PT-50X states all ils well. Air conditioner works but 120VAC to microwave, dishwasher and refrigerator is not existent. Turned on generator, same thing. Inverter when turned on does provide 120 to those items.

I"m stumped!!

A possible tripped GFCI?

Wyatt · 04-11-2021, 12:42 AM

Quote:

Originally Posted by Wayne M

MH is parked in the driveway. PT-50X states all ils well. Air conditioner works but 120VAC to microwave, dishwasher and refrigerator is not existent. Turned on generator, same thing. Inverter when turned on does provide 120 to those items.

I"m stumped!!

Your rig is far more complicated than ours, but if we had that issue, I’d look also to the automatic transfer switch the one that switches from shoreline or generator to the inverter.

Bones2003 · 04-11-2021, 09:24 AM

Quote:

Originally Posted by Wayne M

MH is parked in the driveway. PT-50X states all ils well. Air conditioner works but 120VAC to microwave, dishwasher and refrigerator is not existent. Turned on generator, same thing. Inverter when turned on does provide 120 to those items.

I"m stumped!!

Wayne, I think your coach has two items that act as an "Automatic Transfer Switch" (ATS). The first is on your main power input that switches between shore power or generator. That one seems to be working fine in your case. The other switches between the 120V AC power coming from the first ATS and AC power coming from your inverter. I'm not very familiar with your wiring but that 2nd ATS may be built into your inverter, may be part of your energy management system (EMS), or may be a separate unit. Sounds like that 2nd ATS or EMS isn't switching correctly. On my coach, that second ATS is called an "inverter transfer switch" and is a separate box mounted right next to the inverter.

cbeierl · 04-11-2021, 10:29 AM

Quote:

Originally Posted by Wayne M

MH is parked in the driveway. PT-50X states all ils well. Air conditioner works but 120VAC to microwave, dishwasher and refrigerator is not existent. Turned on generator, same thing. Inverter when turned on does provide 120 to those items.

I"m stumped!!

Here are your wiring diagrams (pick the correct one based on your SN):

42QD (Serial Number begins with 10R96T1)

42QD (Serial Number begins with 10R96T2)

In either case you can take a look at page 6 of the Body, 110 Volt Wiring Installation/Diagram pdf. It looks like the microwave and fridge ARE on the inverter, but the dishwasher is NOT. There shouldn't be any GFCIs involved with any of these three devices.

Wayne M · 04-11-2021, 11:00 PM

Thanks to all. Glad it was in the driveway and we were not on the road! I'll take another look tomorrow but feel it's going to go in the shop.

imnprsd · 04-12-2021, 12:46 AM

* Check your inverter so see if you popped a fuse.

* Get a multi meter with a clamp to check for current on Circuit 1 and Circuit 2... or just probe the breakers with a multi meter for voltage.

When you find no voltage where there should be voltage, then you work backwards from there.

Also you said your ACs work. Do they all work? ...You have roof top ACs right? ...I'm guessing one is on Circuit #1 and the other is on Circuit #2. (I'm not familiar with our coach.)

If you have a basement AC, make sure you have both compressors working by looking at your Amp meter when running on Generator power. Each compressor is about 14A so you should be around 26-28A when both AC compressors are working. If so, then you know you are getting L1 & L2 out of your ATS and all your attention should now be focused on the inverter. (Which you may have overloaded and you just need to reset the pop put CBs that are sometime hidden on your inverter. ...Some are in the back so use your phone to take a picture if you can't see behind your inverter.)

OTHER TIPS TO AVOID THE EXPENSE AND TIME TO TAKE YOUR RV TO A MECHANIC

...Make sure your wires are all tight to your circuit breakers.

...And if all your circuit breakers are hot on 50A service or on generator power, then it's not your ATS.

...Your power shredder board EMS in your main circuit panel and it only affects 3 appliance loads. In my coach, this includes the refrigerator, washer-driyer, and water heater element. So it's not an EMS or PM issue.

...But since we are talking about it, in my older RV I have an Intelletec 620 board located inside the Main Circuit Breaker Box. ...and I have read from other owners that when these boards fail all you have to do is replace the resistors that burn out. (So with your main box open, you should visually inspect your EMS 620 board.)

I'm guessing you have the same system, but IDK?

Circuit 1 does go though the Inverter transfer switch, but it's more of a monitoring switch that turns the inverter on or off. Then then the power out of the inverter goes to the sub-power-panel. I.e, what ever your ATS sends to your Main Panel, and powers C1 and C2 in the main box... Then a separate wire is sent to the inverter and if no AC is detected the Inverter turns on. If power is detected then the inverter goes into "standby" mode.

So to the Main panel you should see both L1 and L2 power, which is 50A each. But your dead appliances are in your sub power box.

Note: These type of breaker boxes alternate bus bars, so every other CB is on the same line.

The picture below with the box open is only my Main Panel, and the other picture is my sub-power panel... fed out of the inverter.

Wayne M · 04-12-2021, 01:23 PM

Thanks, Checked all that "I" can check. Taking to RV physician on Wed.

imnprsd · 04-12-2021, 01:52 PM

Wayne M: What type of inverter do you have?

What type of Air Conditioning do you have? (Roof or basement?)

Wayne M · 04-13-2021, 10:30 AM

Magnum 2500W.

Three roof AC's. L1 showing 120vac, L2 showing 8vac. Zone 1 AC on L1 and runs. Other's do not.

imnprsd · 04-13-2021, 01:09 PM

So your Automatic Transfer Switch (ATS) is the likely problem.

What type of generator does your beast have? Just guessing an Onan 10000?

Wayne M · 04-14-2021, 11:03 AM

Quote:

Originally Posted by imnprsd

So your Automatic Transfer Switch (ATS) is the likely problem.

What type of generator does your beast have? Just guessing an Onan 10000?

Yep, you hit the nail on the head. Crispy wire inside the transfer case. They found it this morning, part in this afternoon.

Thanks everyone for the trouble shooting!

imnprsd · 04-14-2021, 05:09 PM

GREAT!

However, other people helped me get to this point of understanding and in the next couple weeks I plan to overhaul my old Parallax ATS-5070, because I have an Onan 7500 an it needs a 70A neutral, which most of the other ATS manufactures DO NOT provide even though some of their literature says they do.

Parallax 501 or 503 is what you want. And the 503 is over $400. ...Unfortunately, Parallax stop making the ATS-5070 10 years ago, but it was a very good product. Just not cost effective.

...And if you have an Onan 7500 or 8000 generator you need this 70A neutral capability (35A-Neutral per leg off the generator).

...But if you have an Onan 10000 or bigger you can get away with less, but bigger is always better!

...And if you can find a 100A ATS box that would be even better but these are very expensive. And ATS boxes for solar systems in home run big bucks so they are not suitable for an RV when you don't use the RV but a few months out of the year.

My recommendation is that you don't let your repair facility talk you into a less robust ATS -- and don't take their word for it. They are reading old marketing materials in these newer designed ATS boxes and the market has changed in 2019 for the worse if you ask me.

The old style 8-pin Heavy Duty Relays are the way to go or you can buy the Parallax 503.

Note: The Parallax 501 claims they support 70A and they do, but they accomplish this using lower power relays (cheaper) and then they protect those relays with fancy circuit design an wide bus traces in a circuit board. ...And if you ask me, running 35+ Amps through a printed circuit board is nuts! ...But I'm not a design engineer, and that just goes to show Parallax know what they are doing. Also the rewiring into these newer style Parallax 501/503 is harder to do yourself.

The reason for this ATS relay design change, which did away with the 8-pin (contact) Heavy Duty Relays, has more to do with profit margin and competition driving the cost down. So Parallax had to conform.

At one point the market price of these 50A ATS boxes (with 70A neutrals was in the $800-$900 range. Now the cheap stuff, which is apples and oranges, is under $200.

So don't go that route, unless you can find some pre-2015 vintage WFCO or Elkhart or Lyght #LPT50BRD type ATS with the old style Heavy Duty Relays in them.

And get this: These manufactures still use the same part number#LPT50BRD, but the inside guts have changed. ...And they still call them 50A Automatic Transfer Switches... but IMO, you really should NOT use these in an Onan 7500/8000 generator or you will replacing it inside 1 year.

BTW, one month ago I ordered the WSCO ATS and took it apart and found cheep relays. So I returned it. And this is why I plan to rebuild my old ATS-5070 with old style 8-Pin Heavy Duty Relays like in the picture below.

Wayne M · 04-14-2021, 11:00 PM

Thank you for the information.

Wayne M · 04-15-2021, 03:22 PM

Wel, it's all fixed. ATS was most definitely the problem. They went back in with the same model ATS. See the crispier portion?

imnprsd · 04-29-2021, 12:24 AM

WayneM: Who made the ATS that used those burned "Contactor Type Relays" in the picture above?

...And just to be clear you replace that Contactor with a SureGuard 50A-ATS, right?

Notice the difference between the old style, Heavy Duty, 8-Pin Relay in Post #13... compared to the Contactor posted above?

These are not a robust, but it' all you can buy these days since the RV market has changed to using cheaper Contactor Type Relays, which really are rated 40A.

More specifically, when these ATS manufactures market their ATS products and mark the box 50A, they really mean this ATS is for use with 50A Service.

In reality, you really can only run about 50% of the rated current through a relay when powering inductive loads for an extended amount of time. And most of these ATS boxes do not support Onan 7500 or Onan 8000 Inverter Type Generators the require two 35A Neutral Wires, which is what they mean when you seed and ATS that claims they support a 70A Neutral.

The only way to tell is if you look inside and verify the terminal block has enough wire lugs.

So if you have an Onan 7500/8000 you need to make sure you don't buy one of these Contactor-Type ATS Boxes unless you find one rated for 100A; or you will be burning up your AST just like in the picture above much sooner than you think. 1-2 years, TBD...

...It all depends on how much load you run during this time. And the heavier the loads over 20A+ the hotter the neutral wires gets, because while all the current may get delivered by L1 & L2... the sums of the current gets returned thru 1 neutral wire to the ATS.

This why the neutral in your main breaker panel is a larger gauge wire, but when it comes to the relays in the ATS, the old style, 8-pin relay and handle more current then the newer designs that use Contactor-Type-Relays.

Wayne M · 04-29-2021, 10:43 AM

Quote:

Originally Posted by imnprsd

WayneM: Who made the ATS that used those burned "Contactor Type Relays" in the picture above?

...And just to be clear you replace that Contactor with a SureGuard 50A-ATS, right?
[snipped/wm]

Picture shows TRC as maker and Southwire RV as provider. Yes it is a "Surge Guard," but I'm not sure what you are asking for replacing "that Contactor?" The entire unit was replaced and with the original equipment. If the contacts are more robust or not, I don't know.

p.s., Onan 10,000