Looking for Newell Coach Basement Air Conditioning Replacement

[Bikestuff]

Hi all!

I have owned my Newell for about a year (2003 #653). I am just now getting my feet on the ground with the coach, but have been reading and trying to learn from this forum. Thanks for all the sharing and all the knowledge! On top of the information, it is just fun to read how Newell owners think through and solve the problems.

Anyway, I have an issue that could use some help. My coach has a pair of basement air units. One runs the front of the coach and the other the bedroom. Since I got the coach a year ago, I have had nothing but issues with the units. Newell has looked at the front unit 4 times, and has never found an issue, but sometimes cools and other times does not. You would think they could figure out the problem. It never comes on when the fan switch is in Auto mode (still has SCS thermostat). And it seems that I have to put the AC switch in High to get any cool air at all. The bedroom unit has been working well (it has a new thermostat that did away with the HI-LO business) It only has a COOL-OFF-HEAT switch and an ON-AUTO switch for fan. Well just yesterday, that unit quit cooling. It turned out that the unit was frozen-up and when I let it de-thaw it started working again.

All that was to say this....

Is there a viable replacement for basement air units?

Cheers,
bill

[RussWhite]

Hi Bill,

Me again.....

I also have probably the same A/C units as you do on my #530. If you put your question to Newell I expect that will say sure - we will be happy to intsall roof top units for you. That is an option, but the price was way too high for me to consider.

I fulltime and use the A/Cs most of the time. By now I am very familiar with them and the thermostats. My background is as an electrical engineer so most of the stuff comes very easily to me. These are my opinions......

The electrical control portion of the A/Cs is poorly designed. The connectors and relays, and even the lands on the circuit board are marginal at best. But, that stuff is all easily fixed, at least for me. I replaced the connectors, replayed the relays and keep spares, and beefed up the lands where necessary and all units run perfectly now. I have not had a unit freeze up, but should that happen I think I would just pull in out and have a residential A/C service comes and hopefully find the refrigerant leak, repair, and gas up correctly.

Now the thermostat from SCS can be replaced, but I bed you will not find one with the fan options of the original. The fan speed options are kind of importnat as to how the dual A/C units are designed. The SCS is a two stage thermostat and the second stage is activated when the actual temperature is 2 degrees ( I think ) from setpoint. Upon second stage activation, the units starts the second compressor and both evaporator and circulating fan go to high speed if fan AUTO is selected. But, if you select LOW fan speed it effectively eliminates the second stage and you use only the first stage compressor and normal speeds on both fans. This can be a handly feature when managing your power usage. I personally would hate to give that up with any of the replacement thermostats I have seen suggested. I keep a spare thermostat just in case, but I will strive to keep the SCS ones working. I was fortunate to receive great documentation with the coach for the air conditioners and have both wiring and schematic diagrams which are very helpful. One down side of the configuration is it can be difficult to know if both compressors are working correctly. I have a very accurate digital power monitoring system that I can watch to see if the amps increase the appropriate amount when stage two is energized. When I received the coach only one of each pair of compressors was even coming on. When the entire system is working as designed I am very satisfied with the level of cooling.

All this to say - you may want to consider trying to get the bugs out of your existing systems.

[Bikestuff]

As always you bring an insightful and very welcome perspective. Although trained as an engineer, I spent my career doing anything *but* engineering....but may dust off the old soldering iron and see what damage I can do.

Where would you start? Power down everything and inspect the control board? Do I have to remove the unit to get to the control board? (or is there an access panel?). One of my SCS thermostats has already been replaced effectively negating the two stage aspect. Should I start looking for an SCS thermostat or is that a lost cause?

As a last resort, my brother has done some research and says that coleman is making basement units again with the new freon. Around 1200$ per unit.

Thanks again for the help!

Cheers,
bill

[RussWhite]

I am including some pictures of the control boards with this reply. You can easily access the control boards with just the removal of the inspection type plate held on with only one screw. You should see the component side of the circuit board and the connectors. Burned or discolored areas of the board may be visible. You could then turn off BOTH breakers for that air conditioner system, verify with your meter which should be located close to your dusty soldering iron, and then carefully remove the board for a closer inspection. You may want to note the manufacturer of the relays and their model numbers for a little internet ordering later. That is also where I have been able to insert my inductive current probe to measure amps for all the fans, their two speeds, and the compressors. I keep a file of normal amperage's and can help if you think your readings are not normal.

Secretly I hope you or someone else finds a workable basement replacement unit and actually does the job. Be sure to take lots of pictures! It would serve our community well to have a reasonably priced path to a new and hopefully more efficient air conditioner system that would work in the basement location.

Russ

207320742075207620772078207920802081

[tuga]

Bill,

I have Newell #512 and Russ helped me out last year. My SCS AC units kept burning circuit boards; Russ helped me locate some heavy duty wires with rubber snap on connectors. I soldered them to my circuit boards and rigged up my spare circuit boards with the new heavy duty wires - hopefully I will be good to go this summer. My units are 13 years old and still going strong.

I have removed both SCS units and cleaning the coils with acid AC cleaners and rinsed throughly. My bedroom thermostat acts up occasionally but over all it works fine.

My game plan is to replace parts as needed and keep the SCS units as long as possible. I have been told that evaporator coils and condensor coils can be replaced with new ones of approximately the same size. Fan motors and compressors should be somewhat easier to find.

Newell is actively seeking replacements for these units and I am sure that they will have something to offer in the near future if not already found.

Russ has been a big help to me and many others on this forum regarding these SCS units.

Thanks Russ!

[NewellCrazy]

(I have removed both SCS units and cleaning the coils with acid AC cleaners and rinsed thoroughly.)

I have to agree with Tuga on this part. These units can get pretty dirty being down in these basements after a number years of use and a good cleaning while doing repairs would be in good order at the same time.

[Wally Arntzen]

Bill, I have an 88 Coach and I still have the original units. I don't know if they are the same as yours but mine run perfectly. When parked I run all three of them and I can keep my coach as cool as I want it with no problems in the hottest of temperatures. I also have the original thermostats so everything in my coach is 24 years old and still going strong. I really believe that the best thing for all of the equipment in these coaches is to use it as much as you can. Letting stuff sit still and not use because you worry about wearing it out results with when you need it you find out that is not working.
Good luck with your concerns and I wish you safe and happy travels. Wally

[tuga]

Wally you are 100% correct about moving these coaches often. I start mine every week and drive it every other week for about 5 or 10 miles just to exercise everything; shocks, air bags, brakes, AC units, Aqua Hot, generator, run batteries down a little and then charge them up again. I also run the slides out and turn on the in motion satellite system.

[Neweller]

Really appreciate the information and pictures Russ. And I agree with you.

I have heard Coleman is planning on building a lot of these units. The price I have heard is more than $1200 but it also depends on the ton rating. That price wouldn't

be all that bad if it comes with a great warranty and trouble free for a long time. At least Coleman is a large enough company they may not go defunct like both of the

manufacturers Newell Coach used over the years.

[voyager1]

Gentlemen,

Would it not be possible to replace a SCS basement A/C system with a Trane household system?

Then parts would be readily available - or is the SCS a more hardy unit as far as vibration and movement encountered in a motorhome than a Trane unit which typically is installed in stationary applications.

Robert Calrow
Cape Coral, Florida

[tuga]

Robert,

Your idea sounds good but it may have some problems. The weight of the SCS unit is about 160 # I don't how much a household system weighs but I would guess it would be more. Weight is important in a motorhome application. The next consideration would be space; I don't know how you could make a Trane system "fit" in the small area that the SCS is in.

The SCS unit also has the ability to run on 30 amp (1 compressor) when campground power is limited. The Trane couldn't do that.

I'm not an AC mechanic or engineer, but I just don't think that a Trane household unit would work in an RV application.

[smagown]

Robert:

I went the other route, roof airs on my 97 #452. Newell quoted $18-20k and I did it for $2k. My coach doesn't have the mirrored ceiling so that made it easier. The three Duo Therm 15k units are bullet proof dependable and I wired for a 4th right over the bed but have never needed more than two of them at a time. I got the manual controls because ducted units would be very hard to install in the ceiling with all the foam insulation in the way. The cuts in the roof were the only trauma, but after measuring everything numerous times, I let it rip. There are pics in one of my posts of my install. I know you can cut glass but I didn't have to address that. A/C is one less thing I have to worry about!