Georgetown A/C electrical issue

[survyor2]

Hey everyone. This is my first post on these forums so I hope someone has experienced this issue or has some insight.

I have a 2017 FR Georgetown 36B5. I purchased this in January and haven't had any major issues until now. I've been able to address everything so far.

This issue is on generator power. I don't have access to 50A plug-in at the moment.

The front Atwood A/C is not working. No A/C, no heat, no fan. The thermostat is working. The rear a/c is working. I removed the vent cover from the front unit. I tested for power at the unit and no power on the main yellow wire. The rear, which is working, tests good for power.

I have tested continuity on all breakers located under the rear bed. The breaker box has breakers on the left side and right side powered by independent 50A main breakers. The entire left side has no power. The left side is powered by a pink hot wire. The right side is powered by a black hot wire. It seems that the pink hot wire has no power. I have located the transfer switch box from the exterior panel. The pink wire has no power there either.

This is were it gets interesting. The microwave runs off of a 20A circuit breaker on the right bank. I pulled the a/c wire and connected it to the microwave circuit breaker. Now the front a/c works in this temporary configuration because it is no longer working off of the pink hot wire. This seems to prove there is nothing wrong with the a/c unit itself.

Back to the original configuration, I seem to have power on the left and right banks of circuit breakers IF I switch the front A/C 20A circuit breaker off. I can switch it on, off, on, off, on, off quickly and I can test for power in the left bank as power, no power, power, no power, power, no power, etc. As soon has the electric is fully connected to the front A/C the pink hot wire goes dead.

I have replaced the front A/C circuit breaker with new even though the old one tested good. The 2 30A generator circuit breakers are both ON. I have found no burn marks or signs of overheating. No signs of wires rubbing on metal.

Thank you!
Dennis

[CHICKDOE]

let's do the simplest first. have you reset the circuit breakers on the generator itself? it sounds as if you do not have power on one leg. i'm assuming you probably have a 5500 watt generator that put out power on two legs. each leg will have a circuit breaker on the generator. make sure they are not tripped.

do you have access to a 30 amp power pedestal and do you have a 50 amp to 30 amp dogbone adapter? you could plug it into the pedestal and see what runs. not both a/c's at the same time but they may work one at a time.

[survyor2]

Originally Posted by CHICKDOE

let's do the simplest first. have you reset the circuit breakers on the generator itself? it sounds as if you do not have power on one leg. i'm assuming you probably have a 5500 watt generator that put out power on two legs. each leg will have a circuit breaker on the generator. make sure they are not tripped.

do you have access to a 30 amp power pedestal and do you have a 50 amp to 30 amp dogbone adapter? you could plug it into the pedestal and see what runs. not both a/c's at the same time but they may work one at a time.

Yes, Its a Onan 5500. I did reset each 30A generator circuit breaker. I also removed both and tested for continuity across each one. Both tested good.

I do have an 30amp adapter. I will be getting it to my house later for that test. I have run one A/C at a time in the past that way.

[CHICKDOE]

so if you plug into a 30 amp receptacle and are able to run all the 120 volt devices (one at a time) then you are getting power to both sides of your panel. but if you try to run on generator power you are not getting power to the panel on one leg.

this would indicate an problem somewhere between the generator side of the transfer switch and the generator.

are you able to use a multimeter? can you measure the generator input voltage (both hot leads) at the transfer switch? and while in the transfer switch can you measure the output voltage (both leads) leaving the transfer switch. perhaps the generator contactor has a problem.

[bikendan]

Moved thread to the Georgetown sub-forum.

[NXR]

Like Chickdoe said, shut the generator down and pull the cover off the Automatic Transfer Switch (ATS) in the electrical bay. It switches both halves of the RV to either the generator or to shore power. Normally the shore power cord is wired directly into the ATS so it should be easy to find.

If all looks good physically and the connections are tight then start the generator and check to see if the generator is supplying power to both legs of the ATS. Usually there is a single power cable with multiple conductors from the ATS to the inside breaker panel.

Ray

[survyor2]

Reporting back...

I have the RV connected to 30A power. The front A/C DOES work in this configuration. Everything works as it should

I have inspected the ATS. No loose wires. The lower transfer switch engages with shore power. The upper transfer switch engages with generator power, as they should. No green light with shore power. Green light with generator power.

Next, I can check the voltage with the multi-meter. Would it be a good idea to switch the pink and black hot wires at the ATS coming from the generator? If the non-working bank gets power and the working bank loses power this should tell me that the ATS is good and the problem is at the generator.

How can I access were the pink hot wire is connected to the generator? Its not obvious to me visually.

Edit: I have checked the voltage at the ATS
Shore power hot #1 - 122..2v
Shore power hot #2 - 122.1v
Generator power hot #1 (black wire) - 118.7v
Generator power hot #2 (pink wire) - 0.00v

Thank you!
Dennis

[bubbles]

It's electrical, have you given the ATS a good bash?

[CHICKDOE]

Is generator hot #2 (pink) an input lead. From the generator? Is so time to check rd voltage at the generator. You said you have already checked both generator circuit breakers. Won’t hurt to reset both of them. I don’t know how long the generator output wires are. They may not reach all the way to the transfer switch. If so, there may be a junction box with the wires connected via wire nuts may have to check them to see if one has come undone.

[NXR]

No. It is rarely a good idea to swap wires unless you are 1,000% certain you know what you are doing.

You can use a voltmeter to check the voltages coming into the transfer switch and going out to the coach. That's what you need to do. You either have power coming from both generator breakers entering the ATS or you don't.

Usually there is an electrical junction box very close to the generator. Mine is right above and slightly behind the generator. The power cable leaving the generator terminates in that junction box and is somehow connected to the cable going to the ATS. Mine uses large wire nuts. (Ugh)

If you do not have two legs of power from the generator entering the ATS that is the next place to look. It certainly would not hurt to remove that junction box cover and take a look inside with the generator stopped anyways.

EDIT: By the way, Chickdoe, I like the way you think.

Ray

[survyor2]

I had a few minutes today to trace out the wiring. I traced it to a junction box in the access port just forward of the generator. I immediately noticed the melted plastic cap. Only a few strands of wire were left. This has to be my problem.

Thank you

[PopFla]

I believe you're right. Nice detective work!

While you're in that area, you might want to remove those other wire nuts (I agree with Ray...UGH) and make sure there's no other problems in there.

[Mooney 78865]

Originally Posted by survyor2

I had a few minutes today to trace out the wiring. I traced it to a junction box in the access port just forward of the generator. I immediately noticed the melted plastic cap. Only a few strands of wire were left. This has to be my problem.

Thank you

Dang! That's No bueno... Good catch!

[CHICKDOE]

yeah, i think i'd check the other ones also. it looks like they were connecting stranded wire to a solid wire. probably by just twisting the stranded wire around the solid wire and then slipping a wire nut over it. if they tried to tighten the wire nut it may have pushed all of the stranded wire out of the nut so it was barely making any contact with the solid wire.

[Larry-NC]

Originally Posted by CHICKDOE

yeah, i think i'd check the other ones also. it looks like they were connecting stranded wire to a solid wire. probably by just twisting the stranded wire around the solid wire and then slipping a wire nut over it. if they tried to tighten the wire nut it may have pushed all of the stranded wire out of the nut so it was barely making any contact with the solid wire.

If you have to do this (mate solid conductor(s) and stranded conductor(s) in a wire nut, the right way to go about it is to insert all the stranded conductors first, being sure to insert them all the way in, the insert the solid wires as far as you can, and then twist the wire nut. This avoids the "false connection" you have seen where the stranded conductors are not engaged by the wire nut.

This combination occurs frequently in residential situations where a ceiling or wall light fixture connects to solid conductor(s) in the wall.

[Nomore9-5]

Originally Posted by Larry-NC

If you have to do this (mate solid conductor(s) and stranded conductor(s) in a wire nut, the right way to go about it is to insert all the stranded conductors first, being sure to insert them all the way in, the insert the solid wires as far as you can, and then twist the wire nut. This avoids the "false connection" you have seen where the stranded conductors are not engaged by the wire nut.



This combination occurs frequently in residential situations where a ceiling or wall light fixture connects to solid conductor(s) in the wall.

I'd go one step further and use crimp type connectors or the old fashioned Marr 33 - the ones with the screw on the side of the connector body . These cheap twist on connectors that are sold today are a pain in the ----.

[7th day]

After spending most of my life working in the electronics industry I always solder all my connections.

[Larry-NC]

Originally Posted by 7th day

After spending most of my life working in the electronics industry I always solder all my connections.

I often do. If it's in a spot that's subject to flexing or vibration, stranded wires can fail right at the boundary of the solder joint. Something to watch out for.

[7th day]

Originally Posted by Larry-NC

I often do. If it's in a spot that's subject to flexing or vibration, stranded wires can fail right at the boundary of the solder joint. Something to watch out for.

Yes that is true but I always tightly tape the wires or use heat shrink tubing beyond the solder joint as a strain relief.

[NXR]

Originally Posted by 7th day

After spending most of my life working in the electronics industry I always solder all my connections.

Originally Posted by Larry-NC

I often do. If it's in a spot that's subject to flexing or vibration, stranded wires can fail right at the boundary of the solder joint. Something to watch out for.

With decades of experience in electronics and electrical, including electronics repair down to the component level when that was economical, I do not solder all connections.

Most of that career was in the field of avionics (aviation electronics). All connectors are crimp due to what Larry said. Connectors on circuit boards are soldered but their mating connectors are crimped to help assure reliable connections.

Of course, we had high-dollar crimping tools with dies for each size of pin to assure the correct pressure was always exerted. But the reason is the same. Properly crimped connectors are more reliable than soldered ones.

Wire nuts have no place in high vibration environments.

https://www.marinesurveyscanada.com/...nuts-on-boats/

Ray