Sponsored by Winnebago Industries

Author Topic: ac front-rear selector switch  (Read 17152 times)

jcgribks

  • ---
  • Posts: 16
ac front-rear selector switch
« on: July 11, 2010, 07:25:12 PM »
I've got a 1996 Itasca Suncruiser 34RQ.  I can run both front and rear a/c's with the generator running or if hooked up to shore
power, 30amp, only one at a time.  The question I've got is the a/c selector switch up above the microwave is missing.  All the wires
are there but just wire-tied together (by color).  You can see that there used to be a switch installed as there are 4 screw holes showing
something was mounted up there before.  Is there any harm in not having the switch?  Or what is the switch exactly for?  I have tried
to run both a/c's together while pluged into shore power, and they will run, but after a few minutes they trip the 20amp breaker.

Thanks, John
1996 Itasca Suncruiser 34rq, Chevy 454
Olathe, Kansas

34footer

  • ---
  • Posts: 975
Re: ac front-rear selector switch
« Reply #1 on: July 11, 2010, 07:32:07 PM »
I would get a new switch and wire it back to factory specs.
J
1988 Pace Arrow, 34 feet, Chevy 454
                       So Cal

afchap

  • ---
  • Posts: 1161
    • The Empty Nest
Re: ac front-rear selector switch
« Reply #2 on: July 11, 2010, 08:32:57 PM »
You are probably better off with the switch as designed ...I presume it allows you to swith one off, but seems you could do that at the individual ac unit too???

When on 30a power, the "20a breaker" trips??  ...what 20a breaker is that? ...30a power should have a 30a breaker!
Paul ... (KE5LXU), was fulltimin', now parttimin'...
'03 Winnebago Ultimate Advantage 40e
'05 Honda Odyssey toad
Escapees, FMCA, SMART, WIT
http://www.pjrider.com

John Canfield

  • Forum Staff
  • ---
  • *
  • Posts: 11802
    • Jane and John's Internet Home
Re: ac front-rear selector switch
« Reply #3 on: July 11, 2010, 08:40:13 PM »
I would check your wiring diagram - look in the Winnebago and Chassis post near the top of this board for a link.
--John
2005 Horizon 40AD, 2006 Jeep Rubicon Unlimited
Our Horizon projects
Our weather

34footer

  • ---
  • Posts: 975
Re: ac front-rear selector switch
« Reply #4 on: July 11, 2010, 09:51:14 PM »
To run both a/c's you need to be plugged into a 50 amp shore power receptacle.
20 or 30 amp won't run two units long, they should trip when they become overloaded. For safety wire the coach back as intended.
J
1988 Pace Arrow, 34 feet, Chevy 454
                       So Cal

jcgribks

  • ---
  • Posts: 16
Re: ac front-rear selector switch
« Reply #5 on: July 12, 2010, 08:20:58 AM »
The 20amp breaker that trips is the breaker that the a/c's are run through
down in the breaker panel below the refrigerator.

I don't have my Itasca manual with me here at work but I think it says that
to run both a/c's at the same time, the selector switch should be in the front
position.  That's the question I have.  What is the difference between the
switch in the front position and running both a/c's and having the wires tied
together like mine is?  I have 2 thermostats, one for the front and one for
the rear.

I didn't think I could plug into 50amp shore power even with an adapter.
I didn't want to risk melting down any wiring by doing so.  I had planned
to run a separate 20 amp shore line to the rear a/c so I could run both
that way.
1996 Itasca Suncruiser 34rq, Chevy 454
Olathe, Kansas

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 60349
  • RVer Emeritus
Re: ac front-rear selector switch
« Reply #6 on: July 12, 2010, 10:44:13 AM »
The switch is just an interlock to avoid tripping breakers by preventing you from running both at once.  Not a big deal, in my opinion. The two a/cs will generally run on 30A until both try to cycle on at the same time, and then one or both will trip a breaker.   

There is one thing you can try to do without the switch that is impossible with it. It's the start-up surge that usually trips the breaker, not the steady state running.  In very hot weather, you may be able to get one a/c started and running steady and then turn the second one on. If it starts successfully, there is probably enough power to keep it running as long as it doesn't ever cycle off again. 
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

TVEDE6

  • ---
  • Posts: 96
Re: ac front-rear selector switch
« Reply #7 on: July 12, 2010, 12:57:20 PM »
I've a 96/97 Brave with same switch that is still functioning per design. For all the things that can go wrong in a motor home, reinstall the switch and scratch off of your worry list!   Tweedy

jcgribks

  • ---
  • Posts: 16
Re: ac front-rear selector switch
« Reply #8 on: July 12, 2010, 06:05:27 PM »
That's part of why I posted the question, I don't have the switch.  When we bought it last year the switch
was already taken out and the wires wired together.

That's why I don't understand why Winnebago put the switch there in the 1st place.  If you put it in the
front position and are hooked into the generator, you can run both.  If hooked into a 30amp shore line
then I know that I can only run the front or rear only.  When do you ever put the switch in the rear
position?  To me putting it there, in the rear position, just makes sure that no one turns on the front
if you are running the rear and are plugged into a shore line.

John
1996 Itasca Suncruiser 34rq, Chevy 454
Olathe, Kansas

TVEDE6

  • ---
  • Posts: 96
Re: ac front-rear selector switch
« Reply #9 on: July 13, 2010, 09:06:58 AM »
On a hot summer night, the switch goes to "back" when we go to bed--that simple.  Tweedy

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 60349
  • RVer Emeritus
Re: ac front-rear selector switch
« Reply #10 on: July 13, 2010, 11:12:03 AM »
Rear for bed time, front for day/evening time.

We do the same thing on our 50A coach when power is insufficient to run both. We have a two zone thermostat, so we can turn one on and the other off, as needed.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

scottydl

  • Admin assist
  • ---
  • *
  • Posts: 7653
  • Central IL
Re: ac front-rear selector switch
« Reply #11 on: July 13, 2010, 02:52:52 PM »
I have the same setup with a Front/Rear switch on my 1994 30-amp rig.  It's just a 3-way light switch found commonly in household applications.  We also switch our A/C to rear only when sleeping at night.  And I would also recommend getting a replacement switch, so you are not dealing with an electrical hack job that may be shorting out somehow.  It shouldn't be too hard to find a switch.  If a breaker is blowing, then something is not working right.  My 2 A/C's won't even come on together on shore power (regardless of Front/Rear switch position).  I also have a Shore/Generator switch that allows the 2 A/C's to run when on Generator and the genset is indeed running.
Scott, wife, 3 boys... and the dog
- 2008 Forest River Wildwood 32BHDS
- 1995 Chevrolet Suburban C2500 tow vehicle
- 1994 Thor Residency motorhome... owned 2007-2012

jcgribks

  • ---
  • Posts: 16
Re: ac front-rear selector switch
« Reply #12 on: July 30, 2010, 08:01:42 AM »
I just found out something new about my setup without this switch being there.  I was checking over the 5000W generator and noticed that the 20A breaker was tripped on the generator itself.  30A was ok and in normal run/on position.  I re-set the 20a and didn't think about it again until this morning I went to plug into shore power and and a loud buzzing noise was  coming from the generator area.  By the time I got the access door open, the noise quit and the 20a breaker was tripped again.  I told my wife I'm ordering that switch and reinstalling it.  I don't know if something is wrong with the 20a breaker and that's why someone removed the front-rear ac switch and wired both together or what.
1996 Itasca Suncruiser 34rq, Chevy 454
Olathe, Kansas

John Canfield

  • Forum Staff
  • ---
  • *
  • Posts: 11802
    • Jane and John's Internet Home
Re: ac front-rear selector switch
« Reply #13 on: July 30, 2010, 08:12:56 AM »
20 amp breaker is on the gen set, 30 amp breaker is on your coach, or the pedestal? 

You're running on shore power and you somehow tripped the 20 amp genny breaker, or you were running on the genny and you tripped its 20 amp breaker, or you weren't using the coach at all and after you plugged into shore power, the genny breaker tripped?

I'm having a real difficult time understanding the scenario here.
--John
2005 Horizon 40AD, 2006 Jeep Rubicon Unlimited
Our Horizon projects
Our weather

jcgribks

  • ---
  • Posts: 16
Re: ac front-rear selector switch
« Reply #14 on: July 30, 2010, 08:27:21 AM »
Ok, generator is off.  The 30a and 20a breakers on the ones on the generator itself and not the MH breakers.  The 20a I found this week just checking everything out was triped, which I reset.  This is the 1st time that I've hooked up to shore power since resetting it.  To recall, my MH is missing the front/rear ac selector switch above the microwave.  The wires up there are just wired together so I can run the front or the rear a/c.  I never checked the generator breakers before, the 20a may have been tripped since we bought the MH a year ago.  Sometimes on generator power we could run both a/c's and sometimes tring to run both the MH house 20a breaker would trip.  Which makes me think that the generator 20a has been tripped all along.  By hooking up to shore power and with the 20a generator breaker in the on position made the 120v run through the MH and backwards to the generator 20a breaker.  I don't know if this would make a breaker trip or not (running 120v backwards through a breaker).
1996 Itasca Suncruiser 34rq, Chevy 454
Olathe, Kansas

Alfa38User

  • ---
  • Posts: 5833
Re: ac front-rear selector switch
« Reply #15 on: July 30, 2010, 08:45:34 AM »
Quote
By hooking up to shore power and with the 20a generator breaker in the on position made the 120v run through the MH and backwards to the generator 20a breaker.  I don't know if this would make a breaker trip or not (running 120v backwards through a breaker)

Don't think so!!!  The ATS would not permit that, if you have one, and if it is in good working order.

Come to think of it, it could be the root of the problem again, IF equipped and should one side of the relay contacts be welded together!!! If you normally have to plug the power cord into the RV to use the generator, you do not have an ATS.

Just food for thought!!!
« Last Edit: July 30, 2010, 08:53:09 AM by Alfa38User »
Stu
Montréal, Canada 🍁
Snowbird, Naples Florida
Alfa Gold 38 (2000) 5ver (parked!)

"Of course I talk to myself, sometimes I need expert advise!!!"

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 60349
  • RVer Emeritus
Re: ac front-rear selector switch
« Reply #16 on: July 30, 2010, 08:47:10 AM »
A lack of a front/rear switch should not cause the shore power to backfeed to the generator.  The front/rear switch is only supposed to route power from the 30A shore power to one a/c or the other, so I think you have another problem.

You may also have a switch (maybe also missing?) that supplies generator power to the rear a/c, as Scotty described. However, it sounds like your rear a/c may be hardwired to the generator, which WOULD cause a backfeed when shore power is applied. The open genset 20A breaker would stop that.  Hope you didn't damage your genset before getting that breaker off again!

Maybe another Winnie owner with a 30A rig could describe how the genset power to the rear a/c is controlled, i.e. is there a switch or some automatic system that handles that. I can't believe Winnie would leave it to chance that the owner always remembers to flip a switch to avoid a backfeed problem. Just too dangerous.  They might have wired the rear a/c generator feed through the Auto Transfer Switch, but a manual switch like Scotty's is more common.

Or maybe the switch you are missing IS supposed to be the gen/shore switch and not front/rear?
« Last Edit: July 30, 2010, 08:48:43 AM by RV Roamer »
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

John Canfield

  • Forum Staff
  • ---
  • *
  • Posts: 11802
    • Jane and John's Internet Home
Re: ac front-rear selector switch
« Reply #17 on: July 30, 2010, 08:56:40 AM »
I think it's time to study the wiring diagrams!
--John
2005 Horizon 40AD, 2006 Jeep Rubicon Unlimited
Our Horizon projects
Our weather

jcgribks

  • ---
  • Posts: 16
Re: ac front-rear selector switch
« Reply #18 on: July 30, 2010, 09:45:22 AM »
The way I see it looking through the wiring diagrams is that on 30a shore power, the factory Winnebago a/c front - rear selector switch gives power to which ever way you have the switch pointing, ie: front or rear.  If it's in the front position on shore power, then no mater what, the rear a/c does not have any power going to it. If set in the rear position on shore power, then the front a/c does not have any power.  It's just a big "Y" splitter, ether front OR rear but not both.

Now, when you have the generator running, the manual states that you are to put the a/c selector switch in the front position.  The generator has a 30a and a 20a outputs/breakers.  The 30a powers the whole MH except for the rear a/c, the 20a only powers the rear a/c but by the wiring diagram, runs through the front/rear selector switch.

My problem is that someone has removed the a/c front-rear selector switch and just twisted the wires together.  Which when I hooked up the shore power and since the a/c's are wired together, the rear a/c is stil hooked up to the 20a breaker on the generator, this tripped the 20a breaker on the generator.

1st I need to order me a new switch and get it installed.
2nd I need to find out why someone removed the switch in the 1st place.
3rd, did I do any damage to the generator or it's 20a breaker when I hooke up shore power and the 120v ran back through the generators 20a breaker.
1996 Itasca Suncruiser 34rq, Chevy 454
Olathe, Kansas

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 60349
  • RVer Emeritus
Re: ac front-rear selector switch
« Reply #19 on: July 30, 2010, 10:30:58 AM »
As i said, I would be surprised if Winnebago relied on the user to always have the front/rear switch in the front position before turning on the generator. Seems way too risky to me, with a guaranteed backfeed if they don't. But if the genset power runs through an auto transfer switch first, that's not a problem. The only thing that would be wrong if the switch was to the rear would be that the front a/c doesn't work.

Does the switch look like a light switch? It should be just a single pole, double throw switch, which most people call a three-way light switch and available most anywhere. The a/c connects to the center pole and the two power sources are the end poles. I'd get a 20A rated switch, though.

Yikes! I made a big mistake! I was thinking of one type of switch and writing about the other. Alfa38 caught the mistake - see below...
« Last Edit: July 30, 2010, 03:26:19 PM by RV Roamer »
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

geodrake

  • Forum Staff
  • ---
  • *
  • Posts: 5723
Re: ac front-rear selector switch
« Reply #20 on: July 30, 2010, 10:49:57 AM »
The first thing I would do is disconnect all of the wires that have been tied together in place of the switch.  Then determine which wire goes where.  Finally, with all of those wires separated and no longer connected, reset all breakers and apply shore power to see if everything works.  If everything works properly, remove the shore power and crank up the generator to see if everything works properly.  Finally, go back to shore power and crank up the generator to see if everything including the transfer switch works properly.   

If all of this passes, insert a 3-way switch and you should be back to original configuration.
George Drake

Alfa38User

  • ---
  • Posts: 5833
Re: ac front-rear selector switch
« Reply #21 on: July 30, 2010, 12:14:29 PM »
Quote
The a/c connects to the centre pole and the two power sources are the end poles.

Are you sure of that.??

It seems to me that the feed should be in the centre and 1 AC is connected on each of the ends. From the OP's description of the wiring diagram, the 20A from the generator seems like it bypasses the ATS going to the switch and is double connected to the rear AC feeder wire at that point.

Quote
The 30a powers the whole MH except for the rear a/c, the 20a only powers the rear a/c but by the wiring diagram, runs through the front/rear selector switch.

I think TO , not through, because the switch has been placed in the "Front" position, according to your description, and couldn't power the rear AC that way.

I agree with George, that his suggestion is the only way to proceed.
« Last Edit: July 30, 2010, 12:19:53 PM by Alfa38User »
Stu
Montréal, Canada 🍁
Snowbird, Naples Florida
Alfa Gold 38 (2000) 5ver (parked!)

"Of course I talk to myself, sometimes I need expert advise!!!"

mweber (KC9NPT)

  • ---
  • Posts: 132
Re: ac front-rear selector switch
« Reply #22 on: July 30, 2010, 01:41:16 PM »
Just found this thread. I have a '94 Adventurer 34RQ with the switch

Sounds like you're missing the switch that allows you to use both a/c's when on 30 amp shore power. The switch has 3 positions.1 will operate the front a/c, the second operates the rear a/c and the third allows them both to run by cycling them on and off after a certain time period like 10 minutes front, then 10 minutes rear.

The switch fills about 1/2 the space over the microwave.

Not near MH now, so I don't know name on the switch. Will look at it this weekend and get back to you. Also couldn't find it listed in parts manual, but don't know where they would have put it.


OOPs, further digging found this:

http://www.winnebagoind.com/diagram/1996/120536.pdf

Not what I have at all... check page 4.


Merrill
« Last Edit: July 30, 2010, 01:51:30 PM by mweber (KC9NPT) »
Merrill
KC9NPT

2000 Itasca Suncruiser 35U
2002 Wrangler
2005 Liberty
Chicago 'burbs, IL

geodrake

  • Forum Staff
  • ---
  • *
  • Posts: 5723
Re: ac front-rear selector switch
« Reply #23 on: July 30, 2010, 03:19:16 PM »
Most interesting.
George Drake

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 60349
  • RVer Emeritus
Re: ac front-rear selector switch
« Reply #24 on: July 30, 2010, 03:31:08 PM »
Quote
Quote
The a/c connects to the centre pole and the two power sources are the end poles.
Are you sure of that.??

It seems to me that the feed should be in the centre and 1 AC is connected on each of the ends.

You caught me in a major goof, Alfa. Thanks for being on the alert!  I was thinking about the generator/shore switch I had just mentioned and gave the wiring for that rather than the Front/rear switch.  DUH!   Your version of the wiring is correct.

My apologies to everyone - I edited the original to highlight the mistake.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

geodrake

  • Forum Staff
  • ---
  • *
  • Posts: 5723
Re: ac front-rear selector switch
« Reply #25 on: July 30, 2010, 03:33:28 PM »
We have to keep a close eye on some of these guys!
George Drake

asuperheat

  • ---
  • Posts: 20
Re: ac front-rear selector switch
« Reply #26 on: August 01, 2010, 05:55:26 PM »
I just removed mine recently as it had failed. The original design of the switch was so that when the generator was running both a/c's could operate, when on shore power either or could be ran. If you are triping your breaker the wiring now is not correct. There are 4 wires in the box, front a/c, rear a/c, 20 amp circuit from the breaker panel and 20 amp circuit from the generator. When the switch is on front a/c the circuit from the electrical panel goes to front a/c and the 20 amp circuit from the generator goes to the rear a/c. This allows the generator to run both when on because the front is feed through the transfer switch and electrical panel. The rear is feed straight from the generator. The switch is a cam switch and probably pricey. If whoever removed the switch did not wire it back this way then they may have put the 20 amp circuit from the generator, the electrical panel circuit and both a/c's together thinking they could run both a/c's either way but when there is shore power and the genset is running it will trip the generator breaker (they will both be hot). What the previous owner of my RV did is interupt the generator circuit with a plug so it can be pluged in seperate to run both a/c's when on shore power (1-30 amp, 1-20 amp) or pluged into the generator when on generator power but that realy is a diffrent issue. Hope this helps.

Alfa38User

  • ---
  • Posts: 5833
Re: ac front-rear selector switch
« Reply #27 on: August 01, 2010, 07:43:50 PM »
Not sure what a 'cam switch' is, perhaps a type of rotary switch, but your explanation makes a lot of sense
Stu
Montréal, Canada 🍁
Snowbird, Naples Florida
Alfa Gold 38 (2000) 5ver (parked!)

"Of course I talk to myself, sometimes I need expert advise!!!"

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 60349
  • RVer Emeritus
Re: ac front-rear selector switch
« Reply #28 on: August 01, 2010, 09:31:44 PM »
Thanks, asuperheat. A switch like that solves the questions raised earlier in this thread and the 4th wire explains the feedback problem on shore power. 

I'm having dome difficulty imagining how the switch physically works, but the function makes perfect sense
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

asuperheat

  • ---
  • Posts: 20
Re: ac front-rear selector switch
« Reply #29 on: August 02, 2010, 08:07:31 PM »
The cam switch is a switch that has a series of cams inside it to make a series of normaly open and normaly closed contacts. Actualy they can be configured for many diffrent setups all normaly open, all normaly closed or a mix of both. I took mine apart and was quite impressed with it. I choose not to replace it because the way I wired it back works good for me, I only need the rear air in the hotest weather and I have a solution for that. Im sure the switch could be replaced but the wires will still have to be identified and the wires will need to be landed on the right terminals or you will need another switch because if you short it out it's toast. The way mine is the circuit from the generator to the cam switch was interupted in the generator compartment, a plug was installed on the end going to the cam switch and is now permatley wired to the rear a/c. The circuit leaving the generator that use to go to the cam switch now has a receptical installed on it. The plug and receptical make the circuit as one when pluged together and is protected by the circuit breaker on the generator. The circuit from the breaker panel is permately wired to the front a/c so when on shore power or generator power it is protcted by the breaker in the electrical panel. When on shore power I unplug the circuit in the generator compartment and plug it into a 12 guage cord and plug it into a 20 amp plug on the shore power and it is protected by the 20 amp breaker at the pole and I can still run both a/c's without issue. I did not wire the plug and receptical it was done by the previous owner and works well. Wiring it this way it never shorts out with the generator and shore power on at the same time, the circuits are always protected and I can run one or both a/c's with very little effort. This is why I did not bther replacing my switch when it failed.

 

Hosted by Over The Network