September 5, 2014 at 10:36 am #6045
I have two a/c units i think its a Dometic brand, Have to double check this weekend. Front a/c starting omitting a nasty smell not quite like burning but close to it. This weekend i was planning on going on the roof to remove the cover, clean everything up and look to see if i see anything burnt like wiring so forth. All in all if everything looks ok considering the unit is an 05 model would it be recommended to be repaired or just buy a unit and replace it. If repaired i would have to take it in to a shop. If replaced I was thinking I could do it myself. Has anyone replaced one before and if so it is difficult. Also money wise would it just be cheaper to just buy a new one.September 5, 2014 at 10:56 am #6047John R WalkerMember
If you have someone to help you get the unit up and down from the roof, you might want to just replace it since it is almost 10 years old. There are lots of sales going on now for A/C’s
Things to know
Is the A/C controlled by a thermostat on the wall, or are the controls on the unit itself?
Is the unit Ducted or Not?
If controlled by thermostat, the will be control box inside the unit behind the intake air filter. There are different boxes depending on weather you have a 5 button thermostat or 12 button thermostat.
Electric smell, I would bet is the Control Box. Get the model and part number off the box an Google it. Don’t assume the RV Tech knows the difference, lots of confusion even from factory reps.September 5, 2014 at 11:06 am #6049
You asked the perfect questions, Its controlled by a thermostat. It also has the ability to cool or heat. On the inside of the coach you can slide vents on the cover to blow downwards or if you close them it will blow out vents.
The thermostat is digital, front ac is zone 1 you can change from auto, high low. then from cool to heat, heat has the option of gas or electric, gas comes threw the floor and electric comes from the a/c unit. Then of course zone 2 is for the back which works pretty good.
As for getting the unit on the roof, thats no problems. My neighbors have teenagers that can help. Worse case i take it to the office and use the forkliftSeptember 5, 2014 at 11:06 am #6050
I have not replaced RV a/cs but I have a lot of experience in residential a/c. If you use it a lot it could be your fan motor. or possibly a capacitor. If it has been cooling good it can be repaired reasonably. Of course A/C repairs are never cheap. If you go on the roof to check it out make sure you disconect all power to it before. look for burnt wires or fluid leaks around capacitors. ( cylindrical or oval shaped silver, possibly gray devices, with two terminal at the end) Smell the fan motor for an acrid burnt smell. Look for burnt marks or smoky areas around connections.September 5, 2014 at 11:11 am #6051
A burnt smell could also be dust and lint on the heating coils. Probably a heat pump wit a small back up resistance heater. Cheaper to check it out unless you are wanting a reason to change it.September 5, 2014 at 11:12 am #6052
I am the second owner of the coach so i dont know what the previous owner did with it. I was thinking removing the cover, of course shut power off first, Like you said look at fan motor burnt wires smells so forth, then i was thinking dish washing soap and water hose of low to clean off the fins and possibley straghting out any bent oneSeptember 5, 2014 at 11:23 am #6053John R WalkerMember
My guess is you have a 5 button thermostat, since 12 button came out in 2010. The control boxes are not compatible. Also both units need to have the same control box.
Do you know if your A/C is a Heat Pump or just A/C with heat strip in it?
If you remove the air intake filter, you will see the control box, and up above will be a heat strip visible if you have one. It is sounding like you have a Heat Pump, I don’t have experience with those on an RV.September 5, 2014 at 11:31 am #6054
JOhn I will have to check on that this weekend and get back to you. I am not in the mood for a new one. I just dont want to take it to the shop and they hand me a $500 bill and say or we cleaned it up. I am really hoping it is something simple. a shorted out wire or something. That i can replace. I also dont want to be in a situtation of a big repair bill and if i spent a few extra buck i could get a new one. I will snoop this weekend take pics and post and we can all go from thereSeptember 5, 2014 at 2:40 pm #6056
When you remove the cover if it’s a heat-pump there should be a valve in the refrigerant line close to the compressor with three lines coming out of one side and one line in the other side it will have an electric coil on it with 2 wires running to it. I don’t imagine the unit would have a very big resistance heater in it, maybe 3 to 4 kw, only used as backup heating while the heat pump was in reverse operation. Keep in mind a heat-pump will be more money. Do not forget to turn that power off completly before using any water for cleaning. I followed up on a call once where a man did not tur all of it off. His wife found him on the roof of his trailer dead. Also a good capacitor may bite with out power to it. It is an electrical storage device. I found hair from his arm on the capacitor terminals. Anyway just take precautions.September 5, 2014 at 2:50 pm #6058
William , whats a heat pump? When you saying shut the power off, i would assume you mean unplug from the house and disconnect the batteries?September 5, 2014 at 3:40 pm #6059
That should do it. If you use water leave it open for a while to dry out completely. I don’t think you need to disconect the batteries, just main power. A heat-pump is an A/C that has a reversing valve to reverse the flow of refrigerant so that it pulls heat from the outside air in the winter to heat the interior then in the summer it acts as a regular A/C to cool the interior. It also has a defrost cycle to defrost the coil when it starts to freeze up. You may hear it reversing at times, it will make a swooshing sound as the valve opens or closes.September 8, 2014 at 10:50 am #6092
this weekend was a wash. We had down pour friday night into saturday morning. Roof on Coach was wet so i didnt want to walk on it. Sunday didnt help much either. sprinkled all day long. SO i went inside to do inside maintance and got the urge to turn the a/c unit on. the fan turns on nice and runs good, when the compressor went to kick in i noticed the unit bog down real bad. Since i only have 110 at the house i had the generator on and it sure pulled hard on the generator. With that being said is it worth me taking the cover off looking inside or am i better to just replace it?September 8, 2014 at 11:08 am #6093RayKeymaster
I would take a look first James, if you find it is jammed up with dust, dirt and debris, it may just need a good cleaning. Also during a visual inspection you may find a burnt out part or corroded wiring.. A bad capacitor may be the culprit, if it is the compressor itself then it’s likely best to replace the whole unit. Worth a look anyway, usually just a few screws to take a peek.September 8, 2014 at 11:15 am #6094
can a bad capacitor be replaced? If so how hard is it to do?September 8, 2014 at 11:30 am #6095RayKeymaster
[quote quote=6094]can a bad capacitor be replaced? If so how hard is it to do?[/quote]
Not sure about your make and model of AC but on most I’ve seen its very easy, they are usually held in by a clamp and the wires plug on with metal clips.
There are some photos and a vid clip on this post that will give you a general idea of what it looks like in there. Your unit sounds a little more complex but same idea.
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