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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: MarkC on December 03, 2020, 08:26:17 pm

Title: 12 Volt Compressor
Post by: MarkC on December 03, 2020, 08:26:17 pm
My 12 volt compressor in the storage bay just kept running, but didn't sound right. Took it out and pulled it apart and found the small piston "ring" had came apart.  It is a Thomas 405adc38/12.  They have a rebuild kit for about $200.  This is the second Thomas compressor that has gone bad on me.  Was wondering if anyone had any experience with other brands ?

I was looking at the Viair 350C. It is a 100% Duty Cycle compressor that looks like it would fit nicely.  Seems to put out plenty of volume, and the whole unit costs the same as a rebuild kit for the Thomas.

Any suggestions ?
Title: Re: 12 Volt Compressor
Post by: Chuck & Jeannie on December 03, 2020, 09:00:16 pm
Don (Don & Tys) replaced his Thomas with a ARB compressor.  I believe he has been pretty happy with it.  He may see this thread and chime in.  Link below to his install thread.

HWH lung transplant (or aux compressor upgrade) (https://www.foreforums.com/index.php?topic=24636)
Title: Re: 12 Volt Compressor
Post by: Roger & Susan in Home2 on December 04, 2020, 12:10:23 am
This is the one used from 2002 on.  1/3 HP this price is typical. I found a new one for about $900.
THOMAS 1/3 hp HP Piston Air Compressor, 12V DC, -/100 Max. PSI Cont./Int. -... (https://www.grainger.com/product/2KFU8?gucid=N:N:FPL:Free:GGL:CSM-1946:tew63h3:20501231)

Rebuild kit worked fine on my smaller compressor, it cost about $100, $200 now.

Lots of choices,  I think you get what you pay for here.  The Viair compressors don't last. Hdff has one that seems to have failed.

If you can use a 120v version they are much cheaper.  It is worth considering.
Title: Re: 12 Volt Compressor
Post by: Don & Tys on December 04, 2020, 12:49:28 am
It still works like a champ... I am able to use it to raise the whole coach high enough to get my 12" frame blocks in. It has been rock solid, been used a lot, and I would buy it again. ^.^d
Don.
Don (Don & Tys) replaced his Thomas with a ARB compressor.  I believe he has been pretty happy with it.  He may see this thread and chime in.  Link below to his install thread.

HWH lung transplant (or aux compressor upgrade) (https://www.foreforums.com/index.php?topic=24636)
Title: Re: 12 Volt Compressor
Post by: Roger & Susan in Home2 on December 04, 2020, 09:47:26 am
I think this is what Don used,  Looks like a good alternative to either of the Thomas compressors.
Amazon.com: ARB CKMTA12 '12V' On-Board Twin High Performance Air Compressor:... (https://www.amazon.com/ARB-CKMTA12-Board-Performance-Compressor/dp/B0050DI9YQ/ref=sr_1_2?dchild=1&gclid=Cj0KCQiA2af-BRDzARIsAIVQUOcV10VLR0jpq1Ysm6mP2VQH06oWyYzwzs__Q3YobLtwWdgR6QDBEYYaAnHZEALw_wcB&hvadid=282901750958&hvdev=c&hvlocphy=200524&hvnetw=g&hvqmt=e&hvrand=742434532674439484&hvtargid=kwd-300839479096&hydadcr=5492_9590433&keywords=arb+twin+compressor&qid=1607093043&s=automotive&sr=1-2&tag=googhydr-20)
Amazon seller's price is about what everyone sells them for.  Nice to get a wiring harness if you need it.

68 amp max load.
Title: Re: 12 Volt Compressor
Post by: Don & Tys on December 04, 2020, 01:59:36 pm
That is the one! I bought it from an Off Road Warehouse for near that price and I just saw the ARB dual compressor on display at another 4X4 store yesterday. I think that the 68AMP load Roger quotes is the locked rotor specification. I have seen it typically draw between 40 and 50AMPS while running. The LRA must be over to quickly to register on my Magnum ARC50 remote...
Don
I think this is what Don used,  Looks like a good alternative to either of the Thomas compressors.
Amazon.com: ARB CKMTA12 '12V' On-Board Twin High Performance Air Compressor:... (https://www.amazon.com/ARB-CKMTA12-Board-Performance-Compressor/dp/B0050DI9YQ/ref=sr_1_2?dchild=1&gclid=Cj0KCQiA2af-BRDzARIsAIVQUOcV10VLR0jpq1Ysm6mP2VQH06oWyYzwzs__Q3YobLtwWdgR6QDBEYYaAnHZEALw_wcB&hvadid=282901750958&hvdev=c&hvlocphy=200524&hvnetw=g&hvqmt=e&hvrand=742434532674439484&hvtargid=kwd-300839479096&hydadcr=5492_9590433&keywords=arb+twin+compressor&qid=1607093043&s=automotive&sr=1-2&tag=googhydr-20)
Amazon seller's price is about what everyone sells them for.  Nice to get a wiring harness if you need it.

68 amp max load.
Title: Re: 12 Volt Compressor
Post by: MarkC on December 04, 2020, 03:59:55 pm
Don, did you have to upgrade the existing wiring for the ARB ?
Title: Re: 12 Volt Compressor
Post by: Tim Fiedler on December 04, 2020, 04:10:38 pm
LRA event usually 200-300 microseconds
Title: Re: 12 Volt Compressor
Post by: MarkC on December 04, 2020, 05:30:31 pm
Is the item pictured the old style pressure switch for the compress ? And can it be replaced with a new style like Shown below from Amazon?
Title: Re: 12 Volt Compressor
Post by: MarkC on December 04, 2020, 05:34:32 pm
Can I use something like this?

Amazon.com: CompStudio 90-120 PSI Air Pressure Switch Tank Mount Type Thread... (https://www.amazon.com/CompStudio-90-120-Pressure-Switch-Thread/dp/B07KXY2MJF/ref=mp_s_a_1_6?dchild=1&keywords=80+120+Compressor+pressure+switch&qid=1607121171&s=automotive&sr=1-6)

Or does it have to have some sort of relay?
Title: Re: 12 Volt Compressor
Post by: Roger & Susan in Home2 on December 04, 2020, 06:03:09 pm
Mark, Maybe.  This is the one that I used.
Square D by Schneider Electric 9013FHG2J27 Air-Compressor Pressure Switch,... (https://www.amazon.com/Square-Schneider-Electric-9013FHG2J27-Air-Compressor/dp/B000CCJ6QK/ref=sr_1_1?ie=UTF8&tag=foreforums-20&linkCode=as2&camp=1789&creative=390957)
There are others out the that will work.

The compressor comes on when the Essex relay is actuated.  That might be by a switch, by the HWH computer or the pressure switch.

Different years are wired differently.
Title: Re: 12 Volt Compressor
Post by: MarkC on December 04, 2020, 07:05:38 pm
Thank you Roger, I was looking at that one too, just was curious if the other smaller style would work.  Just trying to clean up the wiring in the area.  The PO had quite the nest of cut and spliced wires in there. 
Title: Re: 12 Volt Compressor
Post by: Roger & Susan in Home2 on December 04, 2020, 08:52:49 pm
Mark, I used the shelf brackets in my 2001 for my bigger compressor and the Essex relay. It is all mounted on a 1" baltic birch board.  Pretty easy to do the setup on the bench, install and make final connections.

I moved everything else to a panel assembled on the bench and then bolted to steel framing on the bay wall. I added a dryer and a second filter, an air pressure gauge and a solenoid to add air to the wet tank like the 2003 coaches.  Wiring at the driver's side panel adds a compressor on/off and if it is on the wet tank solenoid valve.

All of the parts on the back wall of the bay makes service easy.

The ARB compressor would work this way.