DuoTherm mark 2 rooftop ac 620426-321

SOURCE: DuoTherm compressor starts but will not continue to run

check condenser fan if running. it will make compressor comes on and off if broken

SOURCE: Compressor doesnt come on in a dometic duotherm

If this is a wall thermostat controlled unit, then check to make sure that you have power coming from the yellow wire on the thermostat when it is placed in the Cool/Auto High mode. If you do not have power at the yellow wire, then you have a bad thermostat. If you do have power, then remove the control unit from the inside of the AC and see if you have power at the Y terminal there. If so, when you turn the thermostat to cool, can you hear a relay clicking in the box? If not, then you have a bad control box. If the relay is clicking, you need to check the power at the compressor relay on the board. It has a black wire to one side and a purple (or blue) wire on the outgoing side. Check to see if you have 120V on the blue wire when the tstat is set to High/Cool. If not, then you need to bypass the freeze switch to make sure that is not the problem. If you do, then you need to go upstairs and check the start capacitor for OK. It is located in the side compartment of the upper unit, it has a small black relay on the top called a PTCR. These often burn out and will cause the compressor not to work. If that is fine, then you go to the top of the compressor to the thermal overload switch. See if you have power at both sides, if so, then you have a bad compressor. If not, then the overload switch is open and not allowing power to the compressor.

SOURCE: i have a duotherm rooftop ac. fan runs fine but

I'm not familiar with these units so this is very general. Your compressor could be shutting down due to low pressure. You would need to get the refrigerant charge checked. It might be due to an overload tripping, which would then reset itself. If you had a schematic or something to send me I could tell you more.

ZJ Limited

• 17989 Answers
• Posted on Jun 01, 2010

SOURCE: I have a duotherm 15000 rooftop rv air conditioner that leaks

On most rooftop air conditioners, you can see the inside (evaporator) coils by looking up through the air return- some models are easier than others, though. This was a Coleman Mach series, so I could just see the coils, but could not access them for a good cleaning, so a trip to the roof was in store.

Getting access to the evaporator coils is not very difficult, you do have to remove the plastic shroud, and then some sheet metal on the front-



Roof Top Air Conditioner- exploded view

This is an exploded view of a DuoTherm BriskAir, but standard Coleman units are pretty much the same. A tip- when removing the screws that hold the sheet metal cover on, pay attention to the screws- there will usually be a few that have a blunt end on them, these are meant to usually go in to the electrical compartments, or where there are wires or tubing. You do not want to find out you put a sharp pointed screw back where it was not used originally.

Once you have the sheet metal cover off, I use a stiff bristle brush to “comb” any large lint off of the fins. Once the “big stuff” is gone, I use a good degreaser- I use VoomRV, because it is PH neutral and a great degreaser, Coleman recommends “Formula 409′. I tend to shy away from most commercial A/C coil cleaners as they are often very harsh on aluminum- they clean the aluminum coils well, but I don’t want the cleaner running down the side of the RV (something you don’t have to worry about in home units).

I soak the coils well, then lay heavy towels over the air intake to catch any water (I put towels inside as well- just in case), then spray the coils off.

This is a good time to check the drain holes for the condensation- there will be holes in the bottom pan on either side of the tray the coils sit in. It’s easy to clean them out. It’s also a good idea to check the gasket-
Air Conditioner gasket measurementmake sure the bottom of the unit is at least 1/2′ above the roof -



It is also a very good idea to check and clean the outside, or condenser coils. Sometimes they will be very clogged- as in the case from Dudes RV Air Conditioner page, but sometimes they might still look clean. Even if they do look clean- clean them any way! In air conditioners that have not been cleaned for a couple of years- and the unit has been used- I will consistently measure a 2 amp drop in current – just from cleaning. You will be amazed at the dirt which will come out of a clean looking coil.

While you are up on the roof with the shroud off, it is also a good time to check the fan motor- some units have oil ports- if yours does, put a few drops of electric motor oil in each port. You can also check the condenser blade. Another unit I serviced ( a DuoTherm) had a fan blade that was starting to go- it was cracking around the shaft attachment, which made it just a little of balance- to the point where it would hit the sheet metal every now and then.

I’ve got to say- RV roof top air conditioners are about the most reliable component on an RV, but they do need regular maintenance. As with most things I talk about, given regular maintenance, they will give years of service. Often RV air conditioners are replaced simply to add new features and lower current draw, not because there is really anything wrong with them.

Hope helps.

SOURCE: what would cause a rooftop a/c unit to leak water

Hi,
There is a drain to run the water outside and it is plugged...this units produces water when running as it dehumidifies the air...

Here is a tip about trouble shooting your air conditioner...

Air Conditioner Trouble -Review the Possibilities
http://www.fixya.com/support/r3571569-air_conditioner_trouble_review_the_possi

heatman101