How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Randall Your Own Question
Randall
Randall, RVIA Certification
Category: RV
Satisfied Customers: 10332
Experience:  RVDA/RVIA Master Certified Technician with many years experience.
21664427
Type Your RV Question Here...
Randall is online now
A new question is answered every 9 seconds

I have a fifth wheel with a Mach 8 air conditioner. Worked

Customer Question

I have a fifth wheel with a Coleman Mach 8 air conditioner. Worked good last season. Now it does blow cold air but with sunny and 75 outside, the inside temp just keeps climbing instead of dropping. The return air filter is clean. I resealed with foli tape between the return air and cold air side. Removed the cover on the rooftop unit but coils appear to be clean. Compressor runs and the enclosed copper pipe on the condenser? (The ones that are enclosed, coils frosted when I ran the air conditioner, indicating to me that it is not a loss of the R410 coolant. I dont know where to go from here. Is it possible the coils are dirty but just not visibly so? I did try compressed air through the coils but no dirt came out. Can you help?
Submitted: 4 months ago.
Category: RV
Expert:  Randall replied 4 months ago.

It sounds like this might be a heat pump version and the reversing valve may be damaged? Can you give me the model number?

Customer: replied 4 months ago.
Not a heat pump version to my knowledge, but here is the model number 49204A879 (from inside the cover on the roof unit).
Expert:  Randall replied 4 months ago.

Let me check on this and get back to you..........

Expert:  Randall replied 4 months ago.

I show that a 49024-879 is a heat pump. A 49204-879 is a regular A/C. So, if you are correct, this may be just a matter that the ambient temps on the roof are so hot that it is affecting the cooling and the air coming out gets warmer. That is about the only explanation possible based on what you told me.

Customer: replied 4 months ago.
It has worked well in the past when we were in New Mexico and the temp was in the mid 90s. Temp today is only upper 70s, so I dont think that is the answer. Is it possible the coils are dirty but just not visibly so? I did try compressed air through the coils but no dirt came out.
Expert:  Randall replied 4 months ago.

Doubtful that is the problem.........especially at that ambient temp. Hard to believe it is losing refrigerant with frost on the lines. You double checked that model number?

Expert:  Randall replied 4 months ago.

Did you check the air filter and coils above that?

Customer: replied 4 months ago.
I just rechecked the model number and it is 49204A879. I took a picture of it when I had the cover off, and I just rechecked the pic.
Customer: replied 4 months ago.
As I said in my original request the return air filter was checked and is clean. I do not know of any other air filter, do you? Are you asking about the coils on the roof? I checked and they are not visibly dirty or clogged. Compressed air 100psi blown through the coils produced nothing.
Expert:  Randall replied 4 months ago.

O.K.........I have no other explanation. I will opt out and let another tech offer something if they have another idea.

Customer: replied 4 months ago.
Does this automatically go to another tech or do I need to do something on my end?
Expert:  Randall replied 4 months ago.

Another tech can offer something if they can and it is available to any of those online. You don't have to do anything. Just don't respond or it locks me back into the question. Thanks!