Another A/C question

[Airbag]

I have the evaporator almost ready to install in the bus. I have been fiddle didling with threads for a couple of hours on the Aeroquip one shot fittings. I have soldered one new tube on the 1/4" tube fitting and played with the threads for a couple of hours with a thread file, scribe, clean, file, thread, un thread, clean, file, thread until the fitting would screw down all the way. Maddening.

My questions are: Are the O-rings in these Aeroquip one shots something special or can I use my assortment of Nitril or Buna-N O-rings? 

Can I pressure check the evaporator and connections with compressed air or should I use Nitrogen and what pressure? I guessing 90 psi is OK? Seems to me that's what we did with the Starships. 

[Nick Badame Refrig/ACC]

Hi Rick,

Yes, you can use your "O" ring set however, you must coat the ring with "refrigeration oil only" to seat it properly.

You shouldn't use compressed air because compressed air has moisture and containminants. Use nitrogen.  Or,

if you own a vaccume pump, evacuate the system and see if you can pull a 30" vac and hold that for 24hrs and that

will also tell you if you have a sealed system or not. Always install a new filter/dehydrator after an open system reapir/install.

Good Luck
Nick-

[mikelutestanski]

Hello;
  I think you should be very careful when you make up the o ring connections. Besides using the refrigerant oil as Nick suggests please treat each joint as an ultra clean unit and make very sure that no dirt or small particles contaminate the assembly. it is very easy to loose the seal on the joint by contamination especially after coating the o ring with oil.
   You should purchase a vacuum meter to check the vacuum and if you go to the carrier transicold site you can review procedures for checking and vacuuming your system including the nitrogen purge and the vacuum purge cycle etc.  Details about how much vacuum to pull for what times are listed on the website.
    It can be frustrating if you dont pay attention to each joint and take precautions to keep each joint very clean during assembly.
    Believe me  few nicked o rings and contaminated joints will cause frustration and be  a painful learning experience.
   Regards and happy bussin   mike

[Airbag]

Thanks guys

I will follow your advise. Is the receiver dryer with the compressor section or evaporator? The manual I have with the unit says nothing about it.

[Nick Badame Refrig/ACC]

Hi Rick,

The filter/dryer is sometimes part of the liquid/discharge line of the compressor on automotive systems.  It is usually very close to the evaperator

and before any metering devices such as orfices or expantion valves. It may be aluminum.

Is this a new system or a salvaged system?  If salvaged, you may be able to have a garage filter your system with their charging station.

Nick-

[bottomacher]

Most of the automotive systems I've worked on have the drier located at the evaporator discharge as part of an accumulator  (GM, usually) and I usually add a filter at the condenser discharge well ahead of the little filter screen at the evaporator intake. I expect there must be at least a dozen different configurations nowadays.

[Airbag]

Hi Rick,

The filter/dryer is sometimes part of the liquid/discharge line of the compressor on automotive systems.  It is usually very close to the evaperator

and before any metering devices such as orfices or expantion valves. It may be aluminum.

Is this a new system or a salvaged system?  If salvaged, you may be able to have a garage filter your system with their charging station.

Nick-

Hi Nick
The sytem is a used Duo Therm split system built in the 1980's for RV use. I bought it from a fellow bus nut. The manual has excellent wiring and installation info but servicing info is just not there. I pulled apart the compressor / condensor box and cleaned everything because of it's exposure to the elements. The epaporator section did not seem like it needed any attention other than a filter cleaning and blow out of the box / fan with compressed air.

[Nick Badame Refrig/ACC]

Hi Rick,

Great! You will then have a 3/8" copper liquid line that you could install a filter/dryer. Tou can look in your area for a

Johnstone Supply or simular to purchace either a sweat in or flare dryer. Try and get a 16ci size.

Post if you need more info
Nick-

[Airbag]

Hi Rick,

Great! You will then have a 3/8" copper liquid line that you could install a filter/dryer. Tou can look in your area for a

Johnstone Supply or simular to purchace either a sweat in or flare dryer. Try and get a 16ci size.

Post if you need more info
Nick-

Hi Nick
I have a 1/4" line and a 1/2" line. Which is the liquid line?    My guess is the 1/4"

[Nick Badame Refrig/ACC]

Ah Ha!

1/4" it is... The Cruisair systems use 3/8 with the 15,000 btu units.  Maybe your Dometic unit is 12,000 btu's.?

Nick-

[Airbag]

Ah Ha!

1/4" it is... The Cruisair systems use 3/8 with the 15,000 btu units.  Maybe your Dometic unit is 12,000 btu's.?

Nick-

It is a 13,500 btu. I am hoping to cool the back half of the bus. I had dreams of running a duct to the drivers seat but that gobbles too much space along the wall. I will install one of those dryers.

Thanks for the help. I am sure I will have more questions.