Dash A/C Compressor Service

[rrueckwald]

Once again the forum proves its worth, and maybe saved my eyes. Thanks John.

Sounds like a job for Coachworx or Parliament.

[Randy Dupree]

Ron,if the AC is still cooling properly don't mess with it.
A little oil goes a long way when it comes to making a mess!
You can add a can of oil with some simple gauges,you can get it all at walmart.
The oil is mixed with the freon,if too much has leaked out it will not cool very well.

[william c harrison]

My a/c compressor was not used by the former coach owner (belt disconnected).
I have heard that these units were not the most reliable so I shudder to think
what repairing mine might entail.

[WTarrier]

Most likely they will want to replace the compressor.
I had that done a year ago, along with a couple of other pricey parts. Works great now, though.

[gcyeaw]

The general opinion is that the dash air alone will not cool very much of the coach. On those really hot days you need to fire up the generator and run your roof AC units. It is commonly believed that the cost of running the generator is equivalent in fuel usage to the load on the main engine running the AC, so most folks just fire up the gennie and run the roof air(s).

If the dash air works, fine. But if it needs a lot of work it will be expensive, and generally doesn't hold up very long. And that R12 refrigerant is outrageously expensive.

[Mallie Lennon]

While on the subject,,, It seem my expansion valve is not working, I would guess a TXV. Does anyone know how to remove it from the 95 BB. It looks like it comes out from the inside.

[giderich]

Mallie, the TXV is located on the right side of the evaporator box in the overhead compartment, on our 89 FC. The TXV can be crossed to a Murray or 4 seasons part # available a O'Reillys.

http://www.wanderlodgeownersgroup.co...TXV+evaporator

In the link above, page down to post #8 and you will see pics, part nos and also several others have worked on the evaporator including Randy and Charlie. Easier to remove the whole evaporator assembly to change the valve.

[QUOTE=gcyeaw;114750]It is commonly believed that the cost of running the generator is equivalent in fuel usage to the load on the main engine running the AC, so most folks just fire up the gennie and run the roof air(s). QUOTE]

This sounded a little odd to me since running a Duotherm rooftop requires converting energy from mechanical to electrical and back to mechanical; whereas, the main engine AC compressor is a direct mechanical connection. My numbers show that the main engine AC is about 1.5 times as efficient; i.e., for each BTU output it will burn 2/3rds as much fuel. If anyone cares I can share my numbers.

For Series-60 equipped buses, when the chassis AC is on the main engine cooling fan switches to high speed. This puts the efficiency in favor of the generator. If your chassis AC switches your main engine cooling fan to high speed then running the rooftops via the generator is more efficient. If you always drive with the engine cooling fan on high speed, as many two-stroke owners do, then the efficiency favors the main engine AC.

I think the conventional wisdom is that the physics favors running the genny to power the rooftops over running them from the main engine driven alternator via the inverters, but in this case I find that the energy efficiencies are essentially equal. The primary reason to favor the generator is to save the alternator and the inverters and to relieve the rooftops from modified sine-wave power.

[fxdwg]

Originally Posted by Mallie Lennon

While on the subject,,, It seem my expansion valve is not working, I would guess a TXV. Does anyone know how to remove it from the 95 BB. It looks like it comes out from the inside.

Mallie,

Dick is essentially correct, except our box is under the dash in front of the passenger's feet. If you open the front and cut a hole in the galvanized box on the passenger side, you should be able to replace the TXV. You'll just have to fab a replacement cover to cover the resulting hole. Make sure you seal it fairly well, otherwise you'll lose some of that cool air.

[Mallie Lennon]

Thanks John. I had decided it had to be in there some where, accessable from the inside dash opening. I really don't see how the whole thing could be removed. I will attempt to get to it when I get a chance. My TXV seems to stuck wide open. Cools a little.