Dash AC Service Ports

[Keith Moffett]

Fair warning.   I just finished this job and made several trips to get more refrigerant.  I let it run while going to the store and when I returned each time the pressure had climbed.  If I had more on hand I would hve put it in right away instead of waiting 15 minutes or so and could easily have over pressured it.
I used the fill ports back by the compressor and installed two large cans or about 42 oz.  I guess t takes awhile for the  fluid to travel all the way forward and then back to read on the guage.

Keith

[Edward Buker]

Keith,

That seems like a lot of added R134A. When it has been sitting awhile and the high side and low side pressure have equalized (2 hours is more than enough) and everything is sitting at ambient and the engine and system has not been run for awhile. Get an ambient outside measurement and if your gauge has an accurate pressure scale on it read the static pressure. This is probably the most accurate way to gauge your charge level. Compare your reading to this chart for the ambient that you have. It should be in the ball park.

http://www.pacificseabreeze.com/tech-library/heat-and-insulation/R134a-PT-Chart.htm

This chart gives you high side and low side pressure for a given ambient while charging but there are assumptions about air flow over the condenser. The condenser fans and inside dash fans need to be on high and full cold while you charge and measure pressure.

http://www.mastercool.com/media/89660-INST_web.pdf

Later Ed

[Gerald Farris]

Keith,
I agree with Ed in that it sounds like you may have overcharged the system a little unless the system was completely empty. If the system was completely empty, you probably have at leak that will need to be repaired. With charging ports at the compressor, you will have low-side readings a little lower than normal because of the long pull from the front of the coach. Therefore, when charging a system with service ports at the compressor, you should be using a full gauge system to properly evaluate the charge state. A partially restricted expansion valve will also give you a low reading for the low-side.

Gerald  

[Keith Moffett]

No longer on my own RV pad.  Will try to get it looked at ina shop.  System was getting cold after I filled it but we had to settle for cool today.  I am thinking leak.  While filling the low pressure tube seemed to have vapor curling off of it in the bend.

Thanks to all
Keith

[Jerald Cate]

I'm haven't been able to schedule service on my dash AC yet since we are traveling, but through further search online I've found that if the condenser fan isn't running it will cause high pressure readings that I'm experiencing.  I checked today and sure enough my condenser fan is not running and my condenser fan relay isn't getting a ground to energize.  If I jumper the ground side of the relay to ground the fan comes on and my AC appears to be cooling.  I don't have a schematic but I'm assuming the ground comes from the AC switch on the dash, does anyone know if that is correct?  Also does anyone have a schematic of the dash AC circuitry they could share?

[Jerry Emert]

I submitted the electrical diagrams to be put in the coach assist area of member services but I don't see them.  I can email them to you I think.  It's big and we had an issue with that before.  I'll try if you want.  Say the word (write).
Jerry

[Jerry Emert]

I submitted the electrical diagrams to be put in the coach assist area of member services but I don't see them.  I can email them to you I think.  It's big and we had an issue with that before.  I'll try if you want.  Say the word (write).
Jerry

  Just remembered I put it in dropbox.  Try this link.

https://www.dropbox.com/s/n8aukdy67t2as7d/Scan%20Jul%208%2C%202014%2C%2017.15.pdf?dl=0

[Jerald Cate]

Thanks for the reply Jerry. Those are the same drawings I have and they are either incomplete or I'm just missing something.  There should be something switching in a ground to the condenser relay (K3), it has a wire going to terminal TB1-10 but I cannot find any drawing that has a wire on terminal TB1-10.  Another dash AC thread running on the forum mentioned pressure switches and a temperature control module, of course none of those components show up on the drawings either.  I assume the temperature control module is part of the dash AC switch panel, anyone know where I might locate the pressure switches?