No AC for my A/C!

[Larry Davick]

I'm an unhappy, sweaty, middle-aged, suburbanite who can not seem to figure out why I have no power to the roof Air Conditioner. I have one roof air
- in front - and it's a newer Atwood uint. Checking for power at the unit I found it was dead. I checked the overhead plug in the rear hallway
ceiling - power. Still I checked the breakers. They operate as expected and current is running when on, not when off. So that's good.

My beloved PO had installed an automatic switch that draws power from the cord or Onan as available, but it looks like there's more to it than just
that. I shoved my phone in to take some pictures that I'll post to the photo site that show a blue box called Gen-Switch and another blue box called
PowerGuard both from Trans-Tech of Plano Texas. I suspect the issues I had with my old air conditioner may have been related to what I'm experiencing
now.

A cursory web search brought up little for Trans-Tech of Plano, so I'm hoping someone here might have a memory of what this kind of thing is. Without
air conditioning we are not happy campers.

Alternately what would you replace this with? Is there current tech that might be compelling enough to rip it out and upgrade?
--
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy

 

[Matt Colie]

> I'm an unhappy, sweaty, middle-aged, suburbanite who can not seem to figure out why I have no power to the roof Air Conditioner. I have one roof
> air - in front - and it's a newer Atwood uint. Checking for power at the unit I found it was dead. I checked the overhead plug in the rear hallway
> ceiling - power. Still I checked the breakers. They operate as expected and current is running when on, not when off. So that's good.
>
> My beloved PO had installed an automatic switch that draws power from the cord or Onan as available, but it looks like there's more to it than
> just that. I shoved my phone in to take some pictures that I'll post to the photo site that show a blue box called Gen-Switch and another blue box
> called PowerGuard both from Trans-Tech of Plano Texas. I suspect the issues I had with my old air conditioner may have been related to what I'm
> experiencing now.
>
> A cursory web search brought up little for Trans-Tech of Plano, so I'm hoping someone here might have a memory of what this kind of thing is.
> Without air conditioning we are not happy campers.
>
> Alternately what would you replace this with? Is there current tech that might be compelling enough to rip it out and upgrade?

Larry,

Is there any reason that you can't rip that thing out of there to get the A/C working and worry about the fine points later?

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[jim kanomata1]

Larry, 0is your coach a Coachman, Royal ?

On Sun, Sep 1, 2019 at 5:47 PM Larry Davick via Gmclist <

> I'm an unhappy, sweaty, middle-aged, suburbanite who can not seem to
> figure out why I have no power to the roof Air Conditioner. I have one
> roof air
> - in front - and it's a newer Atwood uint. Checking for power at the unit
> I found it was dead. I checked the overhead plug in the rear hallway
> ceiling - power. Still I checked the breakers. They operate as expected
> and current is running when on, not when off. So that's good.
>
> My beloved PO had installed an automatic switch that draws power from the
> cord or Onan as available, but it looks like there's more to it than just
> that. I shoved my phone in to take some pictures that I'll post to the
> photo site that show a blue box called Gen-Switch and another blue box
> called
> PowerGuard both from Trans-Tech of Plano Texas. I suspect the issues I
> had with my old air conditioner may have been related to what I'm
> experiencing
> now.
>
> A cursory web search brought up little for Trans-Tech of Plano, so I'm
> hoping someone here might have a memory of what this kind of thing is.
> Without
> air conditioning we are not happy campers.
>
> Alternately what would you replace this with? Is there current tech that
> might be compelling enough to rip it out and upgrade?
> --
> Larry Davick
> A Mystery Machine
> 1976(ish) Palm Beach
> Fremont, Ca
> Howell EFI + EBL + Electronic Dizzy
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[Tom Lins]

> I'm an unhappy, sweaty, middle-aged, suburbanite who can not seem to figure out why I have no power to the roof Air Conditioner. I have one roof
> air - in front - and it's a newer Atwood uint. Checking for power at the unit I found it was dead. I checked the overhead plug in the rear hallway
> ceiling - power. Still I checked the breakers. They operate as expected and current is running when on, not when off. So that's good.
>
> My beloved PO had installed an automatic switch that draws power from the cord or Onan as available, but it looks like there's more to it than
> just that. I shoved my phone in to take some pictures that I'll post to the photo site that show a blue box called Gen-Switch and another blue box
> called PowerGuard both from Trans-Tech of Plano Texas. I suspect the issues I had with my old air conditioner may have been related to what I'm
> experiencing now.
>
> A cursory web search brought up little for Trans-Tech of Plano, so I'm hoping someone here might have a memory of what this kind of thing is.
> Without air conditioning we are not happy campers.
>
> Alternately what would you replace this with? Is there current tech that might be compelling enough to rip it out and upgrade?

Larry
Are you plugged into shore power or are you running the generator?
If you are plugged into shore power have you checked to see if you have power on both hots?
Was the air conditioner working before and now it does not?

--
Tom Lins
St Augustine, FL
77 GM Rear Twin, Dry Bath, 455, FI-Tech EFI, Aluminum Radiator Quad-Bag Suspension
Manuals on DVD
GMC Dealer Training Tapes
http://www.bdub.net/tomlins/

 

[Larry Davick]

I've copied the pictures up to the photo site

http://www.gmcmhphotos.com/photos/g7242-110v-switches.html
http://www.gmcmhphotos.com/photos/g7242-110v-switches.html

Replies

Jim - It's a 1976 Palm Beach

Matt - Any reason? I can't think of one reason - (fat, modestly skilled, uncertain, time constrained, uncomfortable working position!)

Tom - Both with the Generator and on shore power. The air conditioner had worked (beautifully) in the past. There were times when it would work
intermittently and I always figured it was waiting for the caps to load up or some other magic smoke.

It took me some time to appreciate the automatic Generator Switch, as I'd heard others talking about plugging in the Onan / shore power cable. I
don't bother with that, I just plug in to shore power when it's available or run of the Onan when needed.
--
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy

 

[Tom Lins]

> I've copied the pictures up to the photo site
>
>
>
> Tom - Both with the Generator and on shore power. The air conditioner had worked (beautifully) in the past. There were times when it would work
> intermittently and I always figured it was waiting for the caps to load up or some other magic smoke.
>
> It took me some time to appreciate the automatic Generator Switch, as I'd heard others talking about plugging in the Onan / shore power cable. I
> don't bother with that, I just plug in to shore power when it's available or run of the Onan when needed.

Larry
I installed an automatic transfer switch on our previous GMC but haven't gotten to that on this one yet. It is nice not having to not worry about the
plug.
I wonder if you have a bad breaker or possibly one leg of your breaker panel is not getting power from the transfer switch?

--
Tom Lins
St Augustine, FL
77 GM Rear Twin, Dry Bath, 455, FI-Tech EFI, Aluminum Radiator Quad-Bag Suspension
Manuals on DVD
GMC Dealer Training Tapes
http://www.bdub.net/tomlins/

 

[Larry Davick]

Tom,

We think alike. I tested with the Onan all of the breakers and then on shore power. They were all hot. I think I may do what Matt suggests and dig
into that blue box and undo what my beloved PO has done.

Sadly this has sent me down a path looking at RV Power centers. Like a kid in a candy store it's difficult to resist, but I have too many half done
project now to begin something like this.

I'd like to hear what others have done, though.
--
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy

 

[jim kanomata1]

Larry,
Our electrician might be able to look at it solve your problem.
Let me know as he is very good at AC current.

On Sun, Sep 1, 2019 at 9:53 PM Larry Davick via Gmclist <

> Tom,
>
> We think alike. I tested with the Onan all of the breakers and then on
> shore power. They were all hot. I think I may do what Matt suggests and
> dig
> into that blue box and undo what my beloved PO has done.
>
> Sadly this has sent me down a path looking at RV Power centers. Like a
> kid in a candy store it's difficult to resist, but I have too many half done
> project now to begin something like this.
>
> I'd like to hear what others have done, though.
> --
> Larry Davick
> A Mystery Machine
> 1976(ish) Palm Beach
> Fremont, Ca
> Howell EFI + EBL + Electronic Dizzy
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[roy keen]

Modernizing your coach to a transfer system is a nice upgrade but the old way of plugging and unplugging the shore plug is foolproof as far as
simplicity is concerned . The transfer switches are generally a couple of double pole relays . I would remove the covers and check for loose
connections burnt contact points or possibly a bad relay coil. Also check on line for the wiring diagram of your transfer switch it will help you
trouble shoot the circuits. Does it operate with the generator? Did you loose all power or just the a/c unit?
--
Roy Keen
Minden,NV
76 X Glenbrook

 

[Larry Davick]

Curiosity got the better of me. Thinking of Matt's suggestion I pulled off the cover plate and sure enough that Power Guard is connected to the Air
Conditioning and the water heater circuits. I've disconnected the Air Conditioning side and wired it up. I don't have shore power out to the coach
but I'll light up the Onan in the morning and see if I now have power to the air conditioner.

Or if I fry the coach. Either one would be exciting...
--
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy

 

[Ken H.]

Larry,

I think you've found it. I was going to second Matt's suggestion.
Certainly, it's smart to eliminate add-ons, as you've done, before tearing
into OEM equipment which has apparently been working well -- or add-ons
like the transfer switch which has obviously been transferring between
shore and Onan according to your other tests.

I suspect the "Power Center" was installed to overcome a problem with the
shore (or maybe the on-board Main) breaker popping when both the a/c and
the water heater came on at the same time. I'll bet you can deal with
that, by turning off the water heater, better than you can do without a/c!

Ken H.

On Mon, Sep 2, 2019 at 2:13 AM Larry Davick via Gmclist <

> Curiosity got the better of me. Thinking of Matt's suggestion I pulled
> off the cover plate and sure enough that Power Guard is connected to the Air
> Conditioning and the water heater circuits. I've disconnected the Air
> Conditioning side and wired it up. I don't have shore power out to the
> coach
> but I'll light up the Onan in the morning and see if I now have power to
> the air conditioner.
>
> Or if I fry the coach. Either one would be exciting...
> --
> Larry Davick
> A Mystery Machine
> 1976(ish) Palm Beach
> Fremont, Ca
> Howell EFI + EBL + Electronic Dizzy
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[john r. lebetski]

It seems, if I am understanding your given info, that ONLY the roof circuit in non-op, Unless that is the only item on that leg of shore power and
everything else works on board, that it may just he that roof breaker. On ACV if you meter line to load on that breaker you should have zero if
breaker is closed. You can also meter before the breaker to N If you have power there but not after the breaker, it's the breaker. If you have
power after but not at roof, it's connection or branch wiring. If no power before the breaker check main and switch over system If it's breaker, some
aggressive exercise of the trip lever may get you by until it can be replaced.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Larry Davick]

Matt earns a gold star today! I waited for the neighborhood to wake up before lighting up the Onan and I now have power to the Atwood. I'd forgotten
what a wonderful Air Conditioner it is and as a test I tried it in heat mode too. I believe it's a heat pump, so it takes a moment to gather itself
before pumping out heat, but it's effective as a heater too.

Thank you to each of you who replied with such thoughtful responses.
--
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy

 

[roy keen]

If that trans tech unit is just a lock out relay for the water heater and a/c unit all is good with it removed. You don't want to wire around a
transfer unit which I assume is somewhere close by it would be bad if shore power back fed into the generator
--
Roy Keen
Minden,NV
76 X Glenbrook

 

[Larry Davick]

Oooooh. I'll check the generator next time I'm plugged in to shore power, or vice versa...
--
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy