REMOVING THE FILTER FROM THE COOL CAT AIR CONDITIONER/HEAT PUMP

 In the mid-2000s Roadtrek started installing the Dometic  Cool Cat RV  air conditioner/heat pump.  This replaced what had been used previously which was basically a home air conditioner that had a built in thermostat and controls.  The Cool Cat uses an external thermostat and control panel which not only sets the temperature for the Cool Cat's air conditioner but also the Cool Cat's heat pump, as well as the temperature for the furnace in the Roadtrek as well. The initial panel used was analog. Later Roadtrek used an updated by Dometic digital control panel and thermostat. The panel is also the on and off switch for the air conditioner, heat pump, and furnace along with a fan only setting for the Cool Cat - plus a      Hi/Low  speed setting and an Auto/Fan setting. The Auto setting is what is used to enable the Cool Cat to turn off when the temperature that is set is reached and come on again when the temperature drops or increases - depending on using the A/C or the heat pump. 

The Cool Cat like most other air conditioners has a filter in the front of the unit to keep dust and debris from entering the unit with the air that is brought into it.   The filter is foam - mine, as it came from the factory is foam backed with a thin plastic grid that gives the filter some rigidity to remove and put back in.  Some may have this or just a foam filter - replaced by a previous owner of the Roadtrek if your Roadtrek is pre-owned.  Because of how the Cool Cat is installed in the Roadtrek removing the filter can be awkward due to the close proximity of the two cabinets at the ceiling that are on each side of the Cool Cat. The filter does not slide up and out - as many home A/C filters do - but slides out to the side. 

You DO NOT have to remove the front grill to remove or replace the filter in the Cool Cat. If you look at the photo above there is a screw on the outer side of each of the two end round vents on the top of the front of the Cool Cat. These are the screws that hold the front grill panel on.  There is no need to remove those screws. There is a much better way to take out the filter.

1. The first thing to do is OPEN the door on the ceiling cabinet on the passenger side. With this door open you will have a lot more room to move around when sliding out the filter. The filter is going to slide out of the left side.  

2. With the open cabinet door you can get your elbow inside the cabinet to get your fingers onto the edge of the filter through the open slot on that side of the front Cool Cat panel and grab the edge of the filter. 

3. Just slide the filter out toward the open cabinet.  It is flexible and you can flex it out of the slot and completely out. 

4. The filter can be washed or vacuumed clean. If you wash it set it out to completely dry. If you vacuum the filter be careful that it has not become brittle and will disintegrate with the suction of the vacuum nozzle.  There should be no dirt behind where the filter has been in the Cool Cat if the filter has been doing its job. 

5. If you decide the filter needs to be replaced, you can use any of the cut it to size filters sold for air conditioners. I suggest getting one of the foam filters with the plastic grid on the back as it will go in and out of the filter much easier than an all foam filter.  Use the current filter as a template to cut the new filter to size. 

6. When you are ready to put the filter back in, it is going to slide in through the same place it slid out of from the same side BUT there is something to be aware of when putting the filter back in. There is a flexible plastic "clip" that holds the filter in place when it is in the Cool Cat. This does not get in the way of removing the filter but it will stop the filter from sliding back in if you do not follow the next step.

 

7.  Look at the photo above on the left side, inside the grill. You will see the clip that I am referring to. As you see it here, it is in place with the filter clipped down by it. When you start to slide the filter through the slot it came out of (again the open cabinet door next to it makes it easier to maneuver. Put your finger into the vent where that plastic loop is and move the loop toward the front of the vent cover to open the path for the filter to slide in on. The filter is sliding on a groove on the bottom of the cover. Once the edge is past that point it should slide along with the clip down and in place  and you can let go of the loop - but if there is resistance or the filter you have is just foam with no backing - keep that loop up until the filter is slid to the right side of the Cool Cat and stops.  if you are still holding the clip up, let it go.

8. The filter is now in place and the Cool Cat is ready for use. 

I clean the filter when we dewinterize and have used a vacuum to do it. I take the filter out of the Roadtrek, put it down on a flat surface and with a vacuum hose with a soft brush nozzle vacuum the front and back of the filter. 

If you decide that you are going to take the front cover off to remove the filter. When you remove the two screws on the front, it is not just going to come off. There are tabs on the bottom of the cover that fit into slots that hold the cover on. Because the Cool Cat is so close to the ceiling you cannot just pull the cover off when the screws are removed. You have to carefully pull the top of the cover slightly toward you and once you clear right above the cover move the cover up so that the tabs come out of the slots on the bottom holding them in. 

***********************************

Just for further information about the Cool Cat. The Cool Cat is a closed system. There is no way to recharge the refrigerant in the Cool Cat.  There is also no access to any of the mechanical parts of the Cool Cat from the front with the cover off. It is necessary to remove the Cool Cat from the Roadtrek to work on it. This is something not advisable to do yourself.  It may be possible for an A/C shop to cut a charging port into the coolant line for a way to recharge the A/C BUT this can only be done with the Cool Cat out of the Roadtrek and an RV shop would have to take it out for you to bring it to an A/C shop.  Reinstalling involves sealing certain places around the Cool Cat inside the the opening and where it sits on the pan behind. (per the Cool Cat installation manual). Also- The heat pump in the Cool Cat stops blowing hot or warm once the outside temperature approaches 40 degrees F.  If you put it on and the temps outside drop to near or below 40F - the Cool Cat blows COLD!  This can be a big surprise if going to sleep with the Cool Cat on at night and during the early morning ours the temp outside drops! 😦⛄

THE ONAN GENERATOR

 My 2011 Chevy based Roadtrek 190 Popular has the Onan Microlite 2800 KV model generator. Since this model, starting in 2012, Onan introduced a changed generator model  -  the Microlite 2800 KY generator. Since that model there have been two other model Onan Microlite 2800 generators. The most current - that was never used in a Chevy based Roadtrek - is the Onan QG 2800i. It was not used as it did not exist when RT stopped building Chevy based Roadtreks. It can be installed in a Chevy Roadtrek to replace an older model or as a new install.  I am not familiar at all with the Onan that came between the KY and the OG2800i.  All are gasoline powered generators. The only Roadtreks that have a propane generator - installed by Roadtrek - are the diesel engine Roadtreks - none of which are on a Chevy chassis.

In earlier Roadtreks the generator was installed in a cabinet on the outside of the Roadtrek with easy access.  Later, Roadtrek mounted the generator under the chassis of the Roadtrek in the rear driver's side of the van. This location is very difficult to access and requires crawling under the van with very low clearance, reaching up on your arms to open an access panel to the inside of the case, and then craning your neck up to try to see inside the generator to check the oil, change the oil, and reset a circuit breaker and replace a fuse - both of which will be covered later in this article. I have watched Onan service technicians get under the van to work on the Onan much easier by rolling under on a mechanic's creeper. This raises them up enough to better reach in and see inside a little better and not be too high to fit under. They roll in from the side behind the driver's side rear tire.

The position of the generator is rather precarious for the low ground clearance van.  A pot hole and bottoming out can hit the generator. A flooded street can submerge the generator. A steep inclined (or declined) driveway can bottom out the rear of the van and hit the generator. Of course, none of these things are good for the generator. Always be aware of the road and what you are going over when driving a Chevy based Roadtrek with the generator on the bottom. 

The differences between the Onan Microlite 2800 KV and KY models are these. The KV model has an owner accessed altitude adjustment for the motor. The owner can do this easily on their own - following the instructions in the KY manual. The KY model has an owner non-accessible altitude adjustment that -  per Onan - requires a technician to adjust and the addition of a part.  The KY model has a troubleshooting lamp system. The power light on the KY's wall switch flashes a code sequence if there is a problem with the generator. The code sequences are defined in the KY manual. There is NO troubleshooting lamp in the KV model Onan.  The KY also has a priming button to prime the generator before starting. To do this the bottom of the start button is pushed in once or twice to prime the motor with gasoline. The KV model does NOT have ANY priming function. Pushing in of the start button of the KY model only shuts the motor off if it is running.

 The new OG generator model is stated to be much quieter than previous Onan generators. It has a different motor than previous Onan models that is not supposed to require the same exercise schedule of the previous generator which was once a month for two hours of continuous runtime under half a load (the A/C in summer or a plugged in electric space heater in cold weather. The installation of the OG model using the same mounting holes under the chassis that the KY, KV used, requires an adapter plate sold by Onan to make the new case holes match up with the previous drilled  holes under the chassis.

The basics of starting the Onan are covered in our article THE GENERATOR found here. The Onan KV manual may be downloaded here.   For the KY manual, I am not finding a current link any longer for this manual. If you would like a copy of the PDF file of the KY manual that I have, please contact me using the Email Us link in the right column of this page. 

 There are maintenance items that are listed in the manual that are not to be ignored. They include changing the fuel filter, changing the oil (minimum once every year or per hour schedule in manual), changing the air filter, and changing the spark plug. On RV shop that I took my Roadtrek to for the fuel filter change would not do the job without taking the generator down off the bottom of the van. I did not have them do the job. I then took it to an authorized Onan service center that changed the fuel filter with the generator still attached under the van.  If any shop tells you that there is an oil filter - there is NO oil filter.  Some authorized Onan shops will do all of these items when they do an oil change. Can you change the oil yourself - yes. The grade oil to use depends on the area you drive the Roadtrek in the most - and there is a chart in the manual that specifies which oil for which type of environment. Changing the oil means doing this on the ground with you on your back reaching up - or on your elbows if you are on your stomach. Checking the oil means removing the oil cap which has a small dip stick on it. Take out the dipstick and wipe it off. Put it back in BUT leave it on the top - do not screw it back down. The oil is checked with the stick on the top of the oil fill rim.  To drain the oil there is a drain plug under the Onan. There is a specific torque that MUST be used when screwing this plug back in. Only use a torque wrench when doing this set to the correct torque which is in the manual.  I had a shop that did not do this and they stripped threads on the pan. The pan had to be replaced. 

When any work is done inside the Onan inevitably hands working in this tight space are going to hit the circuit breaker handle that is inside the Onan. This circuit breaker is connected to the control board and if tripped or off -  when you start the Onan it will start and run just fine bur NO POWER will come out of it into the Roadtrek. The AC outlets will not work, The air conditioner will not start. The TV will not start. The microwave will not start - in fact the microwave is a good place to see if the breaker is tripped or not. If the breaker is tripped and the generator is running the display screen that is always on when there is power to the microwave will be dark  and off!.  This can happen if you checked the oil or if you changed the oil - or any work was done inside the generator by you or a service tech. The service techs rarely check to see if the breaker is on when they finish working on the Onan.  Below is a diagram from the Onan manual of where the breaker is.  

 

I have made this big because this diagram should be better and it is not. There is an open space in the area the arrow is pointing at. If the breaker is on you will see a small black handle pointing to the passenger side in that  space.  If the breaker is off or tripped, you will not see anything looking up from the ground to inside this area. The handle will be hidden when pointing down. Reach in with a finger and feel for it!  Avoid the fuse which is also in this open space.  When you feel the handle. push it down and then pull it up with your fingertip.  Close up the Onan. Go in and start the Onan and check that there is power - look at the microwave display!  This is the first thing to do if your Onan is running and there is no AC power inside  the Roadtrek!

The fuse is even harder to see. It is a regular auto blade fuse - not hard to replace. You just have to find it and pull it out. There is a sticker (sometimes) on the side of this open area with an arrow pointing to the passenger side that says FUSE. If the fuse lined up with that it would be great - it doesn't. Feel for the fuse - be certain before you pull it out.   WHAT DOES THE FUSE DO?  If the fuse is BLOWN the generator DOES NOT START. It does not crank. It does nothing when you push the switch inside which does not light. IT IS DEAD!  First thing to do if this happens is check the fuse inside the Onan. If it is the fuse it saves a lot of money and trouble to get the Onan fixed or trying to fix it yourself. 

 The Onan uses one half to a third gallon of gasoline in one hour of runtime. The generator will automatically shut down if the gas tank in the van goes below 1/4 tank. This is to prevent you getting stuck with no gasoline running the generator all night.  The generator will also shut itself down if the oil level in the generator falls below full.  This prevents the generator motor burning itself out. 

If you own a Roadtrek with an Onan you already know that it is loud and it vibrates when it is running. You can feel the vibration in the floor. There is an Onan resonator that you can buy that will quiet the motor noise some.  It still vibrates.  Some have added rubber cushioning to above the Onan and where it is bolted into the bottom of the chassis and that can lower the vibration.  I have not done either.

Some may have Roadtrek's later generator system - the "underhood engine generator". This is a SECOND high power alternator installed by Roadtrek under the hood and run by a longer and different belt. The belt is not standard to the Chevy and if you have an engine generator it is advised to buy a spare belt and always have it with you in the Roadtrek.  What this does is provide generated AC power to the Roadtrek by starting and running the engine. The engine is running at idle which Chevy will tell you is not good over a span of hours but Roadtrek insisted it was not a problem. Is this quieter - only if your engine is running is quiet. There are no vibrations - that is a plus. This does use a good amount of gasoline.  Much more than the 1/2 to 2/3 gallon the Onan uses - plus there is a great deal more exhaust that will come from running the engine with more CO to come inside or drift to a neighboring RV. Roadtrek started offering the engine generator to Chevy based Roadtreks around 2015 along with some other advanced electrical system components that previously were tested and sold only on Sprinter based Roadtreks. 

Please get the manual for your Onan, print it out and keep it in the Roadtrek - or put the USB file on your phone or a USB stick to access on your computer when traveling. It goes into much more detail than I have here and it has a troubleshooting chart written out inside.