Community Forums

jefflewin · 08-29-2007, 04:42 AM

I'll make this quick and to the point, i am on my 3rd a/c in the rear, same problem everyone, amps start out good... after 100 outside, amps runs up over 20 triping breaker, dometic 15, 07 dynasty, factory unit replace, dometic unit replace, dometic unit replaced..same problem.. so now here's the quesiton.. do you think if they undersized the wiring, that it could be loosing voltage, casuing the compressor to work harder, causing the amps to increase too much.. this is the rear a/c 44 ft coach..

jefflewin · 08-29-2007, 04:42 AM

I'll make this quick and to the point, i am on my 3rd a/c in the rear, same problem everyone, amps start out good... after 100 outside, amps runs up over 20 triping breaker, dometic 15, 07 dynasty, factory unit replace, dometic unit replace, dometic unit replaced..same problem.. so now here's the quesiton.. do you think if they undersized the wiring, that it could be loosing voltage, casuing the compressor to work harder, causing the amps to increase too much.. this is the rear a/c 44 ft coach..

TXiceman · 08-29-2007, 04:49 AM

Check or have someone check the voltage at the rear unit when it is operating. Also have the amperage checked at the rear nit. Thus would be a good starting point.

Ken

Hitchhiker · 08-29-2007, 05:17 AM

Considering it's tripping a 20 amp breaker it's very possible there is a voltage loss involving the supply wiring to the AC. It could be as simple as a high resistance connection in breaker box. A telltale sign would be discolored insulation at the point of connection to the buss bar and/or the wire attached to the breaker. Often, these screws get loose.

It's easy to check, just take a look in there and even if they look good it's easy to loosen the terminals' screws, move the wires slightly, then re-tighten.

If the wire to the AC isn't at least 12/2 with ground, then undersized wire may be the problem.

jefflewin · 08-29-2007, 05:54 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Hitchhiker:
Considering it's tripping a 20 amp breaker it's very possible there is a voltage loss involving the supply wiring to the AC. It could be as simple as a high resistance connection in breaker box. A telltale sign would be discolored insulation at the point of connection to the buss bar and/or the wire attached to the breaker. Often, these screws get loose.

It's easy to check, just take a look in there and even if they look good it's easy to loosen the terminals' screws, move the wires slightly, then re-tighten.

If the wire to the AC isn't at least 12/2 with ground, then undersized wire may be the problem. </div></BLOCKQUOTE>

Thanks hitchiker, no one has ever looked at the breaker, i have the alladin, so what i do is turn everything off so i show no amps then turn on each a/c and watch the amps, and when they see the amps climbing up, it finally trips after about 24 amps, i will check the breaker wires today, and also check to see what size they are, the middle air does this once in a while, but not very often, the front air works perfect, and never gets over 18-19 even at 106 outside

Matt B · 08-29-2007, 06:12 AM

You might try replacing the breaker first. Believe or not they do wear out. FWIW

Hitchhiker · 08-29-2007, 06:42 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">You might try replacing the breaker first. Believe or not they do wear out. FWIW </div></BLOCKQUOTE>

If the breaker were weak and tripping prematurely at less than it's stated rating, that wouldn't account for the fact that his AC is burning out 3 times. If it were tripping at a current higher than it's stated rating, the question would remain why that circuit is seeing such a high amperage.

I'd be suspect of a high resistance connection first and secondly undersized wiring. I doubt the breaker is the culprit itself.... but if he wants to change it just for kicks, that will in effect give him a renewed connection on the hot leg when it's put in.

adj · 08-29-2007, 01:41 PM

If you are burning up the A/C units, you are probably experiencing low voltage at the A/C unit. As has been expressed here, try getting a voltage reading under load.

If your amperage creeps up, you probably have a corresponding drop in voltage.

That said, I would suggest you check ground connections at the ground bus in the circuit breaker panel. Make sure they are tight and then check the connections on the A/C c/bs.

jefflewin · 08-31-2007, 06:24 AM

well, i think i'll give up..

it has sure stumped a lot of people, just talked to monaco, and there getting there plant mangager involved, check the wires to the breaker, good, tight,check the wires to the a/c.. perfect.. 12 guage, just what they are suppose to be, ran the middle air only yesterday, 1:00 p.m. breaker shuts down, a/c at 24 amps, line voltage at 114... re-set breaker, a/c running at 21 amps.. squited down with water droped to 17 amps for a few minutes then back up... then turned on rear air, it ran for 2 hours..same thing.. front air perfect... remember 3 new a/c in rear.. 2nd in middle... looks like monaco might have a lemon on there hands, will wait for a call back on monday from colburg

adj · 08-31-2007, 07:35 PM

Are all your units 15K? My 13.5Ks are protected by 20 amp breakers. I wonder if your breakers are undersized. Also, these are independent units. If the voltage stays steady with an increase in current, it is being caused by the unit.

Route 66 · 09-01-2007, 02:40 AM

My 15K BTU A/Cs are protected by 20 AMP breakers, and normally draw 15 Amps or less when running.

Sometimes, something that seems to be so easy to diagnose can be so difficult.

Another thing to remember is, that which cannot possibly be the problem, usually is.

Good luck, and keep us posted.

ronboc · 09-01-2007, 03:34 AM

I kinda have to ask the same thing as adj (Dale). Could the breaker be weak or too small?

As a shade-tree mechanic for that kinda stuff, if Monaco is stumped I'd run another heavier-gauge line right from the rear a/c to input to one of the others. That way, it should prove out whether it's the rear a/c circuit or not (altho you do stand the chance of toasting another a/c).

Keep us posted.
Ron

jefflewin · 09-02-2007, 04:49 PM

not to be rude, but i don't think everyone has really read the problem, if the breaker is holding up to 25 amps, how????? could the breaker be weak or too small... the a/c should NEVER be anything close to 25.. NEVER... but i do like the idea of trying a heavier wire, i think i'm going to run from the rear a/c a 10 guage, on the floor ( temporary) directy to the breaker,, and then read amps... but thanks everyone for your great respones... one thing is i know somewhere down the road someone is going to expernice this problem, and hoperfully i can everyone a correct answer...

H. Dossett · 09-02-2007, 05:37 PM

Jeff, sounds like you have a tough one. The kind of problem I get a lot. Taken one at a time, every thing looks good, but the system does not work. I hate those kind of problems.

Looking back through the posts, I didn't see any mention of being at different locations and with the temps being over 100 a lot, sounds like you are staying in one location. Are you in an RV park, or at home hooked up to your own power.

The reason I ask is that if all of this happened at the same location, it could be the 50 amp ?? breaker at the source that is actually bad or weak connection, and the 20 amp breaker is tripping before the 50 Amp gets into trouble. It could be just one leg of the breaker, and likely, the two A/C units having problems are on the same leg, and the third one (the main one?) is on the other leg and doing fine.

I have had breakers and main power boxes go bad. Had a condo water heater that kept tripping its internal breaker because of a weak breaker in the main panal. Also had the same panel to get hot because of a bad connection on the power coming into it. It was a corroded Aluminum wire the insulation melted. Had to cut off one inch and reconnect using an anti corrosion grease on the connections.

Anyway, just something to think about. Good luck and be sure to keep up posted.

Harold