2000 Marquis Basement Air Conditioner

[Jeremy Parrett]

Hello,
 I am experiencing less than sufficient air conditioning temperatures in the coach. I  have the Specific Climate System (SCS) R-VAC 2702 52128.  It has 2 compressors  and is reversible ,providing heat or cooling.  I need to know how to access the evaporator coils.  I have cleaned the condenser coils and replaced the filter.  I have found a 'grill' under the unit towards the center of the coach .It is beside the area where the   water drains out though 2  1 inch diameter holes. If I remove this grate/cover/will I have access to the evaporator coils??
All suggestions will be most welcome.   Jeremy

[Gerald Farris]

Nothing in the AC system is accessible from under the coach. The outside (intake side) of the condenser coils is accessible through the two large ducts on the side of the the coach in front of the utility bay and the outside of the evaporator coils is accessible through the access door in the basement were the filter is located.

The first step in troubleshooting a low cooling complaint on the basement AC is to check the amperage draw on the compressors. You can do this by watching the coach monitor panel that is located above the dinette on most coaches. First turn off the AC and wait 5 minutes, then turn the AC on with the thermostat set at least 10 degrees below interior temperature. Watch the monitor to see how many amps the first compressor draws when it comes on, which is usually a minute or so after the fan starts. A few minutes later the second compressor will turn on which will be indicated by a change in fan speed. Watch the monitor on the other power leg (if the first compressor was on leg one the other one will be on leg two) for the amp draw on the second compressor.

If both compressors are drawing in the 13 to 16 amp range (depending on the heat load), and they are drawing the same amperage, the system is operating to spec. and no repairs are indicated, but if one compressor is drawing considerably less amperage, you have a refrigerant (R 22) leak  that needs to be repaired, If one of the compressors draws no amperage, you have a control board problem or a bad compressor.

SCS Frigette (the manufacturer of the unit) declared bankruptcy and went out of business the first of this year. Before they closed down, they were an excellent source for troubleshooting help, parts, and repairs on the unit. Now it looks like we will have to get the units repaired by a residential AC repair tech after the unit has been removed unless you have a control board problem, and that would have to be repaired by an electronics tech.  

Gerald

[Jeremy Parrett]

Hi Gerald
  many thanks for your informative reply.  I will at least be able to clean the coils now and find out if both compressors are operating normally.  Jeremy

[Jeremy Parrett]

Hi Gerald.
 Ok I checked the control board. All is working as it should.  
There is no access to the evaporator coils after removing the air filter. I am looking at a black plastic top of the unit.  :B
I spoke to Beaver in Oregon and they tell me access to the evporator  coils is  through the basement storage on the cargo side  .I will check this out and report as soon as I have access.  

[Gerald Farris]

The air filter on my 2000 Marquis is located behind the basement access door. It is 18 inches high by 36 inches long. There is a tray on the air conditioner case that the filter sets in, and the top of the filter is taped to the A/C unit with duck tape. I use a pleated filter, and change it once a year. The coils are always clean, and the filter could usually run longer, but I change it to avoid health concerns.

If your filter is inside the coach, I would recommend that you move it to the location directly in front of the evaporator coils that you are accessing in the basement. You are seeing the condenser coils through the ducks on the outside of the coach.

Gerald    

[Jeremy Parrett]

Gerald .
     I know the evaporator coils are located inside the rear storage bay behind a removable access panel where your air filter is  on your coach.
On my coach the removable access panel just reveals a black plastic housing/cover that is part of the a/c  unit casing.  
My air filter is located above the condenser coils in a tray that is accessible above the two large ducts on the outside of the coach drivers side.
Could it be that the evaporator coils are located behind the solid black plastic housing I can see when I remove the bay access panel??  Could that be why your filter tray was moved to this location??
I am considering cutting a door in the black plastic housing . The coils have to be behind this casing .It would be a simple job to fabricate a door for future access.
Directly below this area ,on  the bottom of the coach, is a removable grill about 18 inches x 6 inches through which water drains when the a/c unit is working.
After our trip to Cabo San Lucas,Baja, Mexico this winter the a/c unit is running as it should, showing leg 1 at 13 amps and leg 2 at  18 amps when the 2nd compressor kicks in,but we have no cooling. I believe the Mexican dust has totally clogged up the evaporator coils which I believe have never been cleaned.
If anyone has a similar basement unit and has managed to clean the evaporator coils I would like your input.    Thanks, Jeremy      (who was confused between condenser and evaporator coils..lol)

[Jeremy Parrett]

If anyone has the service manual for the Specific Climate System (Fridgette) 27000 btu basement a/c that was fitted to early Beavers please get in touch.  Thanks, jeremy

[Jeremy Parrett]

Thank you David Henry for sending me the SCS manual with excellent diagrams. I now know that when you remove the access panel at the back of bay with the water pump etc in it you are looking at the black panel/ducting of the a/c unit that ducts the air from the filter ,through the evaporator coils and up through the top exit duct into the coach.
Today I am going to cut an access door into this duct to enable regular cleaning of the evaporator coils.
I also noticed there was no fibreglass insulation anywhere around the unit so I will stuff as much pink stuff around it as I can to minimise the cooling loss.

[Jeremy Parrett]

I have cut an access panel out of the black plastic housing I could see behind the basement storage bay access panel. The evaporator coils were directly behind the plastic panel....about 4 inches behind so plenty of clearance for a cutting tool.
 The coils were very dirty;grey ozidization , black crud.  I used a coil cleaner from Ace Hardware and a soft brush. The coils now shine like new.
  I have pictures of the work I did and the new access panel installed .If  anyone is interested email me .
 Because the evap.coils were so dirty it seems we have now blown the start capacitor or something else on the circuit board as both compressors have stopped working.  
 Sunland RV in Las Cruces are going to look at the circuit board .  Hopefully we will soon have an ice cool coach as we are heading east towards Florida!!
I phoned Victory Climate Systems in Fort Worth. http://scsfrigette.com/  They do have some old parts from SCS systems,but not my circuit board.
  

[Jeremy Parrett]

Sunland RV In Las Cruces were unable to service the SCS Basement unit.
Our  coach is now in Wildwood.FL at Alliance Coach,the old Monaco facility. They tell me the freon level is low in the SCS Basement unit. Both fans and both compressors are running but with low pressure in the freon lines we have no cooling..They need to remove the unit from the coach;install Schraeder valves ,and recharge the unit. The cost could exceed $4000 !!!!!  
We are told that Good Sam's Gold extended service plan may not cover this ,if all that is needed is a recharge. If anyone has  experience with claims like this I would much appreciate hearing about it.
 We are getting quotes for installing  2  Dometic 15,000 btu roof units to be connected to the existing ducting ,controlled by a dual thermostat.
  

[Forrest King]

Price sounds kind of high to replace freon. But first have to find where it leaked out at and repair. I would think you could install the valves with out removing the unit. I know they work a little slow at Alliance, as I had front wheel bearings changed over to wet to the tune of $800.00 there last year.  It was an all day job.  As I have worked in havc for 40 years, I do know a little about mechanical work.

[Jeremy Parrett]

Hi Forrest,
   Thanks for the information.  Do you think the Schraeder valves could be installed from the front of the unit if we cut an access panel into the space between the coils from the the side facing the generator ??  
By removing the water bay, the other end of the unit can be accessed by removing a panel behind the circuit board/capacitor area, but working in there might be very difficult.

[Forrest King]

All they have to do is find a low pressure line and hi pressure line to install the valves.  They can also use saddle valves, but personnel I don't like them, as they are more prone to leak, but I have used them and they work just fine if installed properly. But still will have to check for leaks to see where you are losing the freon. Some units have a real slow leak, and you can charge them.  They will last a year, then just need to recharge every year.  Not a very good route to take, as I would want to repair the leak if it can be located.  With the new electronic testers, they should be able to locate the leak.

[Edward Buker]

That seems well beyond what this kind of work should cost. I do not know if the unit has to be removed to add the ports or what is involved in getting the unit out. Someone who has removed one before may be able to comment on how many hours of work is involved.

I would look on the web for a well rated residential small heat pump/ air conditioning outfit and tell them that you have a basement air system that has been diagnosed as having low freon and you would like them to leak check it, silver solder schraeder valves on the low and high pressure lines of each unit (I believe that both are a problem?), pump them down, check for vacuum leaks and recharge them. I have had R22 air conditioning systems lose some charge over a period of 10 -12 years and then be recharged and run just fine for many more years. The leak rate is so slight that it will never be found and you will spend a lot of time and money chasing it. Tell them that you would like the charge ports located and extended in a fashion that would make it relatively easy to service without removing the unit in the future. That will insure that any future recharge will be relatively inexpensive. There are people that do this type of work everyday that are not charging Alliance rates. Marine air system service folks may be another source of alternative help.

Later Ed

[LarryNCarolynShirk]

Roy Mueller has removed the basement air several times for Lamar.  As he described it, after removing the two air intake tubes and disconnecting the wiring, there are only 4 bolts holding the unit to the floor.  Slide it out, repair and replace.   You may want to contact Roy with questions.

Larry