Cat 277b air condition problems

1. #1clintm2015-09-05 20:59

   the condenser in the cab is most likely clogged up

2. #2Nige2015-09-06 03:26

   Air ducts blocked somewhere by the sounds of it. You'd be amazed at the amount of material that gets in there, especially if you have never cleaned them out before.

3. #3Nige2015-09-06 06:25

   Also the cab air ducts have been updated on the 277B with additional sealing, I would imagine to prevent leaks. If your Serial Number is within the range MDH1-4046 and it has not already been upgraded then it may benefit from the modification at the same time you are cleaning the ducts out. To either clean the ducts or do the sealing modification to the ducts will require the cab to be raised because the complete aircon system has to be disassembled.

4. #4keithnicholson2015-09-06 15:02

   I'll raise cab up and c what I find thanks

5. #5keithnicholson2015-09-06 18:48

   Where is the condenser?

6. #6Nige2015-09-07 03:20

   Here ......

7. #7Mobiltech2015-09-07 10:44

   You actually want the evaporator core.its in the heater box on the left side of the cab.number 5 in picture.the bolts that hold the box in are at #6. This is a big job. To get to the core you have to remove the box from the machine and split it in half. There are clips that hold the box together. You might be able to clean it a little bit with it installed.

8. #8Nige2015-09-07 10:55

   In that case it's here, inside the box marked A ..........

9. #9keithnicholson2015-09-26 18:21

   Ok evap, condensor, both are clean, ducts are clean, fan is worki ng on all speeds but still no volume coming thru,,,,, you can barely feel it at the top vent with it on high,, so what else should i check

10. #10Nige2015-09-27 03:56

    See my post #4 above. Does your machine fall in the S/N range MDH1-4046..? I understand you can see/hear the fan running at all the different speeds but how fast is it actually turning..? You may have a fan motor that's about to crap out. Also does the fan motor spin freely..? Have you tried blocking the vents and maybe using a soap spray to see whether or not you have leaks in the ducting..?

11. #11Mobiltech2015-09-27 11:07

    Is the fan running backwards possibly. I have seen people replace fan motors and switch the wires so it runs backwards. It will still blow but very weak out put. Cat uses 2 different rotation fan motors in some equipment . Also if a piece of plastic or something got in the fan it won't blow very good.

12. #12Nige2015-09-27 13:12

    Did you actually remove the fan/motor assembly when you were checking the system..?