Visit our Popular Forums

nilesrob · 04-09-2007, 06:33 PM

I just pulled our AS out of storage and hooked up to electrical (we have 50 amp service), and I have an electrical challenge. We have a 2005 34' Classic Limited.

The refrigerator stays on "gas" - does not switch to "electrical". And the microwave does not display - seemingly indicating it is not seeing electrical service. On the refrigerator, I put an electrical tester on the outlet that it plugs in to, and it tests fine (all outlets test fine).

When I checked the electrical panel, there was one or two circuits tripped, so something definitely went awry. Unfortunately, I switched the circuits off and then on before really noting which one(s) had tripped.

The panel breakers are all on, the outlets all test properly, but the refrigerator does not sense electricity and the microwave does not display at all.

Any ideas welcomed!

lewster · 04-09-2007, 07:14 PM

Brad,

You checked the outlet for the microwave AND the outside one for the fridge, and they both have 120VAC to them? If that is the case (and be sure that you actually measure the voltage with a good RMS voltmeter) then you have other problems that are not related to your AC supply wiring. Both of these appliances require a minimum AC voltage to operate, and a test light will not tell you if that threshold is reached.

If you remove the black cover on the control box at the back of the fridge, you'll see a fuse or two. Be sure that they are in tact by doing a continuity test, not just a visual inspection. Also check your owner's manual on the micro to see if it has an internal fuse or circuit breaker.

If the AC supply is good and the protective devices (fuses) are good, then you have control board issues.

PM me with the results if you need more direction.

nilesrob · 04-09-2007, 07:38 PM

Lew,

Thanks - I'll try this out. Unfortunately I can't do it until Thursday - about to go out of town, but I may get back to you after I check this out more fully. Thank you either way!

Dan@LED4RV · 04-10-2007, 08:38 AM

If you unplug the refrigerator and it does not trip the breaker then you know it is the fridge. And from there it is most likey the 110 heating element. If this is the case then maybe you can change the element with out taking the unit out. You will need the model number and Ser# to get the right element.

Mike Lewis · 04-10-2007, 08:53 AM

Turn all the breakers off again--not just tripping them but push them PAST off then back on . I think you'll find them ok then. ---pieman

raebaker06 · 04-10-2007, 09:56 AM

Try the AC outlet with a 100 watt light Bulb. That should tell you if the AC supply is giving current. Never measure your electricity with a digital meter . The are too sensitive A Radio crap meter should tell you.

Rae

lewster · 04-10-2007, 07:31 PM

Quote:

Originally Posted by raebaker06

Try the AC outlet with a 100 watt light Bulb. That should tell you if the AC supply is giving current. Never measure your electricity with a digital meter . The are too sensitive A Radio crap meter should tell you.

Rae

Rae,

Could you please explain the logic of your quote above. Respectfully, I take complete exception to your statement!! Where did you get this information and what are your qualifications and training in electricity and it's measurements?

A large part of my RV Certification exams dealt with AC, DC and their proper and precise measurements, which are critical to correct diagnosis of electrical problems.

Are you telling me that my $400 Fluke 87V digital RMS multimeter is not to be trusted with the information that it is giving me? It is perhaps the finest, most reliable and accurate meter of it's type available! I'm afraid that your '100 watt light bulb' just won't match up!!!!!!!!!!!!!!

The point of my post was not to see if there IS current, but to determine PRECISELY HOW MUCH voltage is present, as a low voltage supply situation can be an indicator of other problems in the trailer. Your light bulb just can't tell me that!!

Please clarify...........................

I'll be glad to explain the process of RMS and why it is so precise when measuring AC voltage if you like.

HowieE · 04-10-2007, 08:11 PM

If you are measuering voltage at the freg. and microwave outlet but neither work but a simple lamp will light when plugged into those outlets I would suspect you may have been hit by lightning and blown the controls or fuses of both.

Most microwaves have a fuse accessable once the case is removed. Also as mentioned above check the fuses in the freg control panel. Remove one end of the fuse, in the freg., from the holder to test to insure there is no secondary path

The controls for the freg operate off the 12 volt system. The 120 volts are only used for the heating element in the chimney.

If the fuses check out OK the last test would be power each by an extention cord plugged into a circuit outside the trailer.

herrgirdner · 04-10-2007, 08:38 PM

Lew, old buddy, most of the analog multimeters I've had experience with have been RMS meters. I think what was meant was that the digital meter gives a bit too precise a reading for this application. I've got a 77A Fluke, and don't like to use it for T/S because I don't need to know that the line voltage is 122.23 volts. If it is 120 volts as read on my Triplett 630, that's just fine. I do agree that using a light bulb isn't a good idea, it's hard to estimate the applied voltage from looking at the brilliance of the filament.
But for a gross check, light or no light tells you if the circuit is energised. But, that's all.
regards

Tinsel Loaf · 04-10-2007, 09:17 PM

Just because you have the best meter in the world it only displays what it detects not what the voltage will do or the element in the refrigerator will do. Sometimes you may have 120 volts but the device wil not work under a load.

herrgirdner · 04-11-2007, 12:00 AM

RGR
I admit it!
The 100 watt light bulb will show if the power outlet will support it. A meter by itself will not do that. How about if we plug the light into one of the duplex outlets and use the meter to read the voltage at the other? If the light is dim, the voltage will be lower than the nominal 120/115 volts. If this is the case, unplugging the light bulb ought to increase the voltage reading, and it indicates wiring/breaker issues.
regards

Safari Tim · 04-11-2007, 12:18 AM

Might be a long shot but you could check for a tripped GFI outlet. They feed other outlets down stream and can cause an outage.

nilesrob · 04-11-2007, 06:11 AM

I was thinking maybe lightning - I'll check out some of these ideas when I return home Thursday. All good ideas - thank you!

lewster · 04-11-2007, 07:03 AM

If you read post #2, I state that there is a voltage threshold for many appliances. This is a specific voltage and a light bulb will not will not provide you with that information.

Sure, a light bulb will tell you if a circuit is energized, but we're looking for a root cause for appliance non-operation here, and specific line voltage may be a contributing factor. It's just one more tool to troubleshoot a problem that may have multiple causes.

herrgirdner · 04-11-2007, 09:59 AM

RGR, Lew. A thought just drifted through, while waiting for the web guru. A quick check which would eliminate or definitely point to the wiring, etc., would be to use a stout (circa 12 or 14 gauge) extension cord. Plug it into shore power and then plug the microwave into it. If the console lights come on, its the trailer electrical system that is at fault. If the microwave checks out OK, might plug in the fridge and see if it also comes on..
good luck.
regards

lewster · 04-11-2007, 06:24 PM

That IS the best way to isolate the component to see if it will work on it's own. We do this on a regular basis for refers to see if the control boards are bad, or if they have a bad cooling unit by taking the heating elements out of the control board and plugging them directly to a KNOWN working 120VAC circuit. It would work for a micro as well.

nilesrob · 04-16-2007, 08:56 PM

Thanks again for all the advice. Here's what I did...

I picked up a voltage meter and tested all the outlets - all came in close to 120 (+/-) volts. Like Lew suggested, for the refrigerator I did find a blown 5 amp fuse - located from the road-side cover at the rear of the refrigerator. Replaced it - bingo!

As to the convection oven/microwave, I removed it from the cabinet, but there are no actions that can be taken on this unit (Sharp Carousel) except to bring it to a service dealer. I did that today - we shall see. The units sell for around $200 - $300 new so the repair will have to be minimal.

I still don't know the source of what I can only surmise was a voltage surge - lightning or whatever. Anyway, it looks like we are on the road to recovery.