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larry_cad's avatar
larry_cad
Explorer II
Oct 12, 2022

DP weird design "feature"?

This may or may not be interesting, but it happened yesterday to me and I am borderline astounded.

We have a 40' Fleetwood DP. We have had it for quite a while and yesterday I had to do some work on the two Atwood heaters, primarily I am getting ready to remove one of them to replace the blower motor which is squealing. I got the info from the label and now have to find a new motor. (Important note: mounted on each of the heaters is a toggle "ON/OFF" switch which I switched off in preparation for removal.)

Got my information for the blower motor and went into the coach to do some cleaning, etc. and it got warm in there so I turned on an A/C at the thermostat.

Guess what? No A/C. Hmmmm. Went to the back of the coach and turned on the rear A/C. No A/C!!

Fiddled around and checked shore power, breakers, 120V up at the rooftop, etc. for about half an hour. All good. Sat down and scratched my head for a bit, then as a wild sorta last resort, I went outside to the basement where the Atwoods are mounted, and turned on the "ON/OFF" switches for the heaters. Guess what? The A/C units now work.

Got out my Atwood owner manual and studied the schematic, and there it was: The 12VDCcomes into each of those switches, through a circuit breaker, and to the heater relay, BUT, it also goes up to the thermostat (you know, the one that controls the A/C too!)

I learned something new to me after many years of ownership. Wasted a lot of time, but I guess it was worth it.

:h:S
Class A
  • dougrainer's avatar
    dougrainer
    Nomad
    Oct 12, 2022
    Both Suburban and Atwood. NOT NEW or weird. Been that way for over 25 years. OEM's realized it takes 1 less power wire to run for the AC wall tstat. Remember, just not that switch. Blown fuse for the furnace and you also have no power to the wall tstat. Some OEM's tap off that wire BEFORE that switch. Newmar used to do that and Newmar installed a 5 amp fuse at the furnace(hidden). To protect the AC wall tstat circuit. Your diagnosis tells why a good 12 volt circuit tester or multimeter should be used before replacing parts. LOTS of RVer's replace parts without checking for pos and neg at the appliance. You did and saved money. Doug
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Oct 12, 2022
    larry cad wrote:
    (Important note: mounted on each of the heaters is a toggle "ON/OFF" switch which I switched off in preparation for removal.)

    Got my information for the blower motor and went into the coach to do some cleaning, etc. and it got warm in there so I turned on an A/C at the thermostat.

    Guess what? No A/C. Hmmmm. Went to the back of the coach and turned on the rear A/C. No A/C!!


    First that switch is called a Circuit Breaker on the Furnace wiring diagram.

    Second it supplies not only power to the Furnace. but to the THERMOSTAT as well. Turn it off and nothing HEVAC works. (Save the dash parts)
  • dougrainer's avatar
    dougrainer
    Nomad
    Oct 12, 2022
    wa8yxm wrote:
    larry cad wrote:
    (Important note: mounted on each of the heaters is a toggle "ON/OFF" switch which I switched off in preparation for removal.)

    Got my information for the blower motor and went into the coach to do some cleaning, etc. and it got warm in there so I turned on an A/C at the thermostat.

    Guess what? No A/C. Hmmmm. Went to the back of the coach and turned on the rear A/C. No A/C!!


    First that switch is called a Circuit Breaker on the Furnace wiring diagram.

    Second it supplies not only power to the Furnace. but to the THERMOSTAT as well. Turn it off and nothing HEVAC works. (Save the dash parts)


    IF you actually knew what your talking about. There are 2 versions. Older had only a Circuit breaker. newer versions have both the ON/OFF switch AND a Circuit breaker. Some have the combo On/Off-Circuit breaker. Doug
  • chuckftboy's avatar
    chuckftboy
    Explorer
    Oct 12, 2022
    Here is a brain teaser, Technically a switch is a circuit breaker and a circuit breaker is a switch LoL!
  • Gottahaveit's avatar
    Gottahaveit
    Moderator
    Oct 15, 2022
    Learned something new as well last weekend. Had had the Mhome at the shop for some body work repair. Picked it up and batteries dead..found the solar power charger had burnt a wire. Not that big of a deal so they plugged it in and we brought home and went camping. (Ordered new solar charger) When camping found out Fridge would not work on AC. No big deal but no ICE if not on AC. After a few days of searching turns out the GFCI had tripped in the bathroom and that controls the AC to fridge :E So long story short the Body shop did some welding on an outside door and Hubby assumes they grounded to the MHome and blew the panel.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Oct 15, 2022
    dougrainer wrote:


    IF you actually knew what your talking about. There are 2 versions. Older had only a Circuit breaker. newer versions have both the ON/OFF switch AND a Circuit breaker. Some have the combo On/Off-Circuit breaker. Doug


    The OP said he'd had that unit for a while.. Indicating it's an older one.. and yes the circuit breaker is also the on/off switch.
    Looks like a switch. in fact I'd swear it was a switch, not a breaker, based on it's design.. You will notice I did not say it was a Circuit breaker.

    I SAID THE WIRING DIAGRAM SAYS IT'S A CIRCUIT BREAKER.

    Atwood says it is. Not me.. And yes I do know what I'm talking about for I had one myself. It failed. I had to figure out why. (Did too, after all the problem was electronic and that's what I do).
  • dougrainer's avatar
    dougrainer
    Nomad
    Oct 15, 2022
    wa8yxm wrote:
    dougrainer wrote:


    IF you actually knew what your talking about. There are 2 versions. Older had only a Circuit breaker. newer versions have both the ON/OFF switch AND a Circuit breaker. Some have the combo On/Off-Circuit breaker. Doug


    The OP said he'd had that unit for a while.. Indicating it's an older one.. and yes the circuit breaker is also the on/off switch.
    Looks like a switch. in fact I'd swear it was a switch, not a breaker, based on it's design.. You will notice I did not say it was a Circuit breaker.

    I SAID THE WIRING DIAGRAM SAYS IT'S A CIRCUIT BREAKER.

    Atwood says it is. Not me.. And yes I do know what I'm talking about for I had one myself. It failed. I had to figure out why. (Did too, after all the problem was electronic and that's what I do).


    This is what the OP stated.
    "The 12VDCcomes into each of those switches, through a circuit breaker, and to the heater relay"
    SWITCH then CB then RELAY. As I stated, you know nothing except what you try to find on the Internet. There are various schematics for both Atwood and Suburban depending on the year and various models. YOU always fail to understand that. Doug
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Oct 15, 2022
    And as I said The DIAGRAM says it's a breaker.
    Also no reason other than cost not to have 2 breakers and a good reason (Safety) to do so if there is a wire run between them that rodents can dine upon
  • Dale_Traveling's avatar
    Dale_Traveling
    Explorer II
    Oct 21, 2022
    One of the reason I refer to 12VDC and the life blood on a rig. You can get by without 120VAC but not so much without 12VDC.

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