SCS Air Condition Unit

[Laurence Mitchell]

Just got home with our "New to us" RV.  Purchased it knowing the AC unit wasn't working properly.  Had a NRVIA inspector check out the unit before we purchased and stated the both compressors are working but the unit isn't blowing air.  Does anyone know a shop that can service this in Arizona?  We live in Tucson.  Also the Dash air isn't working and wondering if that will need be serviced by Cat shop.

I'm sure we will have more questions!

Thanks in advance for any assistance.

LTM.

[Steve Huber Co-Admin]

The basement unit is effectively a house style unit with 2 compressors. Since the fan(s) aren't running, I'd suspect either the control board, located behind a panel on the right side when the outer door is open or a faulty thermostat. Check for signs of overheating around the connector on the board as that is a common failure point. The boards are available and repairable at Flight Systems in TX (?). If the fans don't run when the t'stat is set to fan only, I'd suspect the t'stat. Others on the Forum know more about these units so hopefully they will provide input. Manuals are available in our Coach Assist library.

The dash AC is a standard automotive unit with the compressor in the engine compartment and the rest of the hardware under the front cap. Any reputable RV or AC shop that works on RV should be able to diagnose and repair it. In Tucson, Premier RV has received good reviews by BAC members.
Steve

[Fred Brooks]

Greetings Mitch,
   Received your e-mail, Welcome to the family. I can t-shoot all your issues and help resolve most of them. The ones I can't, we will come up with a strategy to address them.
   Just finished Greg Ross's Samsung refer installation, came out Great, Looks just like Steve Hubers coach. Give me a call at 520-309-1260 to set up a time to come by my shop.

   Blessings & Joy, Fred Brooks

[Laurence Mitchell]

Thank you for all the info.  Looking forward to meeting with you Fred and getting our projects started...
We are looking forward to many years of "Glamping" when the better half becomes a traveling nurse.

Mitch

[Gerald Farris]

LTM,
The basement A/C unit in a 2000 Marquis has 2 fan motors. One is for the evaporator coil that blows inside the coach, and the other one is for the condenser coil that draws air through the ducts at the rear of the kitchen slide and exhaust it under the coach. If both fan motors are not working, I would suspect the circuit board as Steve said, but if only one fan is not working, it is usually the fan motor. The 2 speed condenser fan motor is no longer made, but you can just match up to the same motor in a 3 speed model and only use the medium and high speed connections and it works perfectly.

I owned a 2000 Marquis for 14 years and had to repair the basement A/C unit several times, so if I can be of help, just call (713-254-4156) or if you work with Fred Brooks and he runs into a problem that I can help with, he can call at any time. Just remember that everything in your basement A/C unit can be repaired or replaced, but since the unit went out of production in 2010, you can not buy a new replacement unit. The only new basement A/C units that are still in production will not fit your coach. 

Gerald

[Roy Lewis]

Hi Gerald, I has texted with you about our basement air. We have been without air for a month but installation is next wk. Coleman has compressors that work and we had both replaced as it is a pain in the rear to pull them out and we had our board rebuilt by Flight Systems in Penn.. Can hardly wait to hear them up and running! 

[Laurence Mitchell]

Gerald, Steve,

Thanks for info and the offer to help!! I have Fred Brooks fitting me in his busy schedule to check to see what is going on with that unit!  Hoping it can be repaired without pulling the unit. 

Mitch.

[Gerald Farris]

Mitch,
There is nothing that can be done to repair a SCS basement A/C unit except replacing the circuit board without removing the unit. However, if your circuit board fails, it is normally due to something in the A/C unit that is drawing too many amps. I learned this the hard way by repairing a control board without addressing the compressor issue and it lasted a week. So the A/C unit will usually need to be removed to correct the reason the board failed. Removal of the SCS A/C unit is not as hard as it looks. I can pull one in less than an hour, and in fact I would much rather R&R (remove and replace) a SCS unit than any roof mounted unit.

I have owned a coach will a SCS basement A/C unit for over 14 years (2 coaches) and I have had 4 control board failures. Three were from excess amperage draw by a compressor, but the last failure was on my Solitaire and I traced that failure to a defective Onan control module that was allowing the generator to produce 140 volts at times. The SCS control board has a device on it that will short the power circuit to ground if it sees excess voltage to protect the components. 

Gerald

[Fred Brooks]

Hi Mitch,
    Gerald is correct and the voice of experience, When we trouble shoot your unit, I hope you can be with me so you will see how we check compressor operation and amp draw as well as blower motors performance, also check t-stat output commands and pc board response. I know you are excited to get going with your new adventure and look forward to helping you soon!
  Blessings & Joy,
Fred Brooks