Front A/C not working

[wingtrike]

We have a '01 Alpine 38FDDS. It is connected to shore power at our home. The rear A/C works fine, but the front unit doesn't come on. I have checked the thermostat and its settings for temp, etc.
Need some help in troubleshooting the unit, breakers,etc.

Thanks,
Alex

PS: The front A/C did work a couple of weeks ago.

[Old Scout]

The obvious checks are the 120V breaker in box [in/around bath area] and making sure you have current to that leg of the breaker box [ie, all other outlets, appliances in coach are working except for this A/C unit]. If a leg is out, check transfer switch and shore power. Once those issues are checked, it usually means something wrong with the A/C unit--harder to diagnose much internal to the unit without tools/knowledge [IMO].....

[Jim A]

There is a chance the problem is with the shore power itself, not the coach. Last year I had problems with the front AC not working. It had worked fine earlier in the day while running the generator. I plugged into the 30 amp outlet instead and the front AC came on and worked fine. And it worked fine the next place I plugged into 50 amp service.

Check to see if it runs when using the generator. That will narrow your search if nothing else.

[wa8yxm]

Suspects list in sequence order

If your rig is 50 amp, then the 50 to whatever adapter you are using may only be powering one leg, or if you are plugged into a 50 amp RV outlet (I always recommend people installing home RV outlets go for 50, even if I did 30. I wired my own, properly, too many hire it done.. WRONG and end up trashing the electronics in their rig)

Next is plug and socket issues.. Bad cords do happen, as do bad plugs and bad sockets

Now we come to the automatic transfer switch.. Rare, but it happens

Then if you have an EMS..

Next we have screws loose.. Many RVers have screws loose.. With power UNPLUGGED and generator if any OFF, and I mean OFF and unplugged, the plug where you can see it if possible, open the breaker box and tighten... EVERTHING.

Next is bad breakers, (Oh, check for tripped breakers too) and bad wires

Finally.. Bad AC

NOTE: My rig has Carrier V Remote controlled A/C units.

So much dust got between the actual sensor and the top of the "Window" in the cover it could not see the remote sending it commands.

A bit of cleaning (Remove the cover and clean it) fixed that just fine.

[wingtrike]

My receptacle for the m/h is a 50 amp service that was installed about 2 months ago. A licensed electricican installed it at our home.
I did check and reset the breakers, then I started the gen. After a couple of minutes the front a/c came on. 2 1/2 hours later, I went back to the m/h to check it. The rear a/c was working, but not the front.
I will call the electrician who did the install of the receptacle.
I have not driven the coach since the last of March, so I doubt if any screws have worked loose.

Thanks for the advice and have a great day!

Sincerely,
Alex

[Renipladlo]

If you have a digital VOM meter, you can check the output of the receptacle yourself, which will save the electrician call. You should have 120V on each leg of the 50A output. You will have 120V between the hot leg and the neutral leg, and 240 across both legs. If you have that, then check the transfer switch as mentioned above, MAKING SURE EVERYTHING IS DISCONNECTED AND OFF. You can get a bad/lethal shock if you hit a live circuit. If you have the proper volts/amps coming in, make sure you have closed breakers for the front a/c unit, check to see if it's really getting 120V's. Then have someone who is qualified, make sure the start/run capacitors for the a/c itself are in the correct range. Otherwise, you can call an Certified RV Tech, who can diagnose the problem.

[Old Scout]

If the front AC runs on genset but not on shore power, the problem is either bad shore power or one leg on yr transfer switch is shorted or gone bad. A simple 110/220 test probe will determine if both legs of the 50 amp shore power are hot. This test could save you the cost of an electrician house call to come out and tell you that his work was fine and its your coach (transfer switch???).

[wingtrike]

Thanks so much for the replies. I think I can attribute the problem to 3 sources: me, myself, and I.
When the 50 amp service was installed, the coach (and power cord) was at my dealers. I think I told the electrician to install the 50amp service for 110. He will be here soon to verify and change to proper voltage.
For whatever reason, I didn't think of this when I posted the original question.
Have a great day everyone.
I hope I haven't caused any damage to the MH.

Sincerely,
Alex

[Renipladlo]

Ok - now make sure the electrician know some things he may not be aware of.

50 Amp RV outlets have two 50 amp legs of 120V power. IT's not like a stove connection.

As you can tell from the plug, you have a ground, two 120V legs and the neutral connections. Make sure he hooks it up correctly, or you could fry all the electronic/electrical devices in the motorhome, and cause a heck of a fire. As you can see from the shape of the plug, it's not a normal type of unit.

See this link for an explanation: http://www.myrv.us/electric/

[takepride]

Monty:

The plug and outlet for an RV IS exactly like a stove. Both use the same configuration at the plug.

U = ground
Blade directly below is neutral
Blades to the side at both 120 volt hot (and interchangeable)

The difference comes with what is done with the ground system (wire and bonding). Inside the RV and at the pedestal it must remain separated from the neutral wire (white) throughout (panel, appliances, plugs, connections, boxes, cord, etc) and be separate until it reaches the subpanel at the house with it's true ground-to-earth. That is the location where the neutral and ground are bonded (to the panel which is bonded with both electro-ground rod and waterline).

It might be noted that some residential stoves do combine neutral and ground (inside) and therefore are commonly wired without a continuous, uninterrupted ground. However, the 50-amp plug configuration is the same. It's just where it goes inside the wall, hence the warning to not just plug your cord into just any residential outlet. One needs to check the residential outlet first.

Now the 30-amp plugs face a different problem since some are one leg of 120 volt (like RVs) and some are two-pole and either a ground or neutral. Those outlets need checked before using your adapter (dog bone).

[F&D ABQ]

Originally Posted by wingtrike

I did check and reset the breakers, then I started the gen. After a couple of minutes the front a/c came on. 2 1/2 hours later, I went back to the m/h to check it. The rear a/c was working, but not the front.

Sincerely,
Alex

Alex, not clear whether you kept the generator on for 2-1/2 hours or just turned it on long enough to get power to the front A/C. If the former, you have problems in the coach for sure. Even if it's the latter, your problem could be the transfer switch rather than the receptacle. It's not uncommon for the transfer switch to fail.

[azloafer]

When we had the dedicated 50 amp RV line installed at our house we had the electrician look at this info first even though he has done a lot of RV lines. This was given to me from the forum:

Installing the 50-amp 120/240-volt 3 pole 4 wire grounding Service.

DO NOT CONFUSE the 50-amp 4 wire 120/240-volt (14-50R) Service with the OLD APPLIANCE 50amp. (10-50R) 3 wire 120/240-volt service.
The 50-amp service has 4 wires with two 120-volt HOT feeds. This service is a STANDARD 120/240 50-amp 3 pole with 4 prongs. Parts needed to install. 1 DOUBLE POLE 50-amp 120/240-volt Breaker. 1 14-50 Receptacle and 2 (HOT), 1 White (Neutral) and 1 Ground. Correctly sized wire Plugs and Receptacles are available at Lowe's, Home Depot, Camping World and Electric Supply houses.

RECOMMENDED wire sizes for 50-amp: 25 feet -#8, 50 feet -# 6 and 100 feet -#4. you may get along fine with longer runs with #4.

Joe

["007"]

The most important thing for your electrician is this link , that Renipladlo displayed, have him follow it and you both should not have a problem..