Working on the 322C. System had an obvious leak at the condenser so that is simple enough. However, even with a proper charge, I am not real impressed with the vent temps, prompting me to possibly dig deeper in the system. Still trying to decide that. Anyone know if this is a TXV system or fixed orifice? Today is 100F, and I was showing about 92F going into the return air filter on the floor, and vent temp is 65F. Certainly better than outside but I am not sure what is going on yet. By the pressures, it sort of looks like a blockage in the system, but not enough a guy would really want to spend a day tearing apart. If things were easier to get to, I would sure like to gather some temperatures in other areas to better spot the issue. Any thoughts on the normal performance of the C series? I had concern the fresh air door was pulling in ambient air so I put something over it on the back of the cab but really does not act like that is at issue right now. The compressor is certainly pumping it up.
In my experience the C series A/C works OK. The main problem I find is the evap coil getting blocked with dirt. How is the air flow from the vents? Is the compressor cycling? Serial number required for more accurate info.
I vote for dirt packed evaporator, but, as stated above, serial number please. Torn apart enough of the C machines to tell you that, if you have the capacity to evacuate and refill the refrigerant, pull the whole box. My 330C machines would get so cold that the sweat on the outside (under the storage box) would penetrate the temp blend actuator, resulting in a sheared shaft on the blend door. Changed two in situ, and pulled the third hvac box out completely. Just for giggles, turn off the coolant flow to the heater core and retest outlet temps (valve at engine or hose pinch pliers).
What are the pressure readings for the low and high side. And air flow is important. Also any heat from the heater core will negate the cooling. If your blend door isn't working properly then it will effect the a/c.
Serial HEK004** Data points to a blockage at the TXV. I just don't want to hear the answer of how fun that will be to get to????? basic symptoms are: 1. higher than acceptable vent temps. 2. Low side pressure will pull down to 30 with full charge 3. High side pressure is sneaking up past acceptable ranges. 4. My usually proof test. Shut machine down and observe gauges to see how long to equalize. It should be fast. I walked away after 5min. that is not normal. I was thinking about the filter/drier but there is nothing in the system that can lock those pressure like that other than the TXV. It is possible the bulb fell off, but just a guess. Issue is getting to it. At least it shows that the compressor is solid!!!! If compressor was even weak, the pressure would equalize much faster.
What was the "proper charge" amount installed? Low side @ 30 sounds normal. What does "high side sneaking up past acceptable ranges" translate to, in pressure readings? With that said, it's, obviously, a TXV system.
Compared to some excavators, these aren't too bad to remove. Not a walk in the park but at least it isn't in the seat base.
Well, low side was not stable and kept dropping, while high side approached 350psi. All while not getting cold air. That usually is a starving evap but I can't get to it to run SH tests on it. Oh, IIRC, the charge was 1lb, 7oz. that is a steel badge in the cab and it seemed to jive about right with where I was headed with charge anyway. There was a point where head pressure was just too much. Typically a TXV system needs to be tuned via SH/SC but since the badge was in the cab, I went with that. I was told the machine had a leak anyway so sort of figured I would be revisiting and I am....lol
I REALLY appreciate the breakdowns guys! BTW, any chance we can stumble into a filter/drier part number? Depending on what I might find, I may swap that out. Sometimes they go bad and plug the system. I 'almost' appears if I can get the top off, I might have access to the valve just behind the seat. It is really hard for me to ignore this blaring issue while the system is down anyway.
Dryer part number is 1761902. Pretty common. Here in Aus we can get them from NAPA. In my experience the tag in the cab is an accurate figure for the correct charge. I think if you take the whole thing out for a clean, you won't regret it.
Almost get the top off? T30 for the storage box fasteners. 16mm for the bolts holding front panel to floor. TXV outside the hvac box (easily accessible after storage box, followed by front panel removal).
^^^ How about a T60....lol and the hood is off! Since I am agile, I am going to see what I can do topside. I do not have time to pull the seat and entire hvac unit. Can I get the top off? I reached into the intake and found grime and a candybar wrapper. I want to go deeper. (that's what she said). Also, Another issue I avoided is the vent selector does not work. Select defrost, etc, it is stuck in position. Which motor are we looking at? I barely got the hood off before the bugs started eating me alive so planning attack for tomorrow. At least now I have access to the evap pipes so I can run more tests but probably will be low on gas tomorrow.
T60???? Kneel backwards on seat (after removing headrest) and remove the T30 fasteners at top and in floor of storage box. Lift storage box out and place aside. Using very long extension, while still kneeling backward on seat, remove the two 16mm headed bolts holding the front beauty panel on. Lift and remove beauty panel. Voila, instant access to TXV and exposed lines.
Sir, Already done did that! The hood is off! Now asking about where else I can go without the full R&R? really like to scrub the evap if possible. Also need to know which motor is the one for the vent selection. It is stuck. I suspect motor is still good but it's stuck somewhere. But hell yes, that TXV is right there! Way better sitch than I planned on.
Sorry. T30 are on the D models. I've torn too many apart to not confuse them. I don't think the approaching 350psi is too high for a 100° day, and, with a live heater core, wouldn't it be reasonable to shut off the heater valve at the engine, regardless. And, if the mode actuator isn't responding, would it not stand to reason that the blend actuator may also not be responding?
What about fault codes? Does your AC controller look like this?
Yes it does and I was given the diagnostics here and though there were a couple erroneous codes, I cleared them and they did not return. Apparently the blender system is not monitored so it has no clue on that part. As for any other faults, no, there have not been any that would indicate what is going on with the cooling system. Right now I am pretty interested in getting to the evap coil and getting some line test temps. OH, for accuracy, no the pic you shared is not quite right. This one has two control rotary knobs for temp and fan speed control. EDIT: missed ya on the blend doors. I will certainly find a way to shut down the heater core for testing but I know for certain some level of function works for temp selection. She will run ya out in heat mode and I can roll over to cool and get that. As for the mode selection, I found two issues. One that the door levers themselves are hard to operate due to crap in them. And I was able to make the actuator motor work but not too well. I took it apart and it's full of dirt! I could probably clean and save it but a new one is not too expensive. It is going to get a proper seal like they should have done!!!! It is ridiculous how much dirt is in it!
I ain't saying that this chart is correct, but...
Like literally ALL of those require more juice than the badge indicates in my machine. However, I will note, that badge is extremely hard to read. Usually I can dial a system based on my SH/SC but I didn't have places to gather my temps. As well, I suspect pushing more juice in the system will certainly push head pressures to extremes. At some point I know it is just too much for 134. I hope I am wrong and I find a simple fix. I am giving the TXV a second thought if the evap is plugged up. It can cause this.
FWIW (refer to Cmark's post above) our annual A/C maintenance on excavators included a full clean out, a replacement dryer and every 2 years an accumulator if the system has one. By the sounds of the dirt you've found I'd guess nothing has been replaced in a long time. With that maintenance the refrigerant charge on the tag seemed to work pretty well.
Nige, curious what you consider a "cleanout"? I was able to get the hood off the inlet side to get access to the evap. I'll get you guys a pick for fun. What is apparent is likely the fresh air filter has never been changed and the bottom has deteriorated to a point there is no filter. As well, the fresh air door is a poor design and will never totally seal fresh air out, so right now it is free to pull dirt in and has done just that.
Could you guys set me up with part numbers for the 2 cabin filters? Hoping I can score some aftermarkets somewhere.
Seat & base out. Removal of complete Cab HVAC unit & disassemble. Disassembly & cleaning of cab air ducts if applicable. Some cabs have separate ducting, some don't. Lubricate pivots on things like blend doors with dry film silicone lubricant. Replace any damaged/worn parts. Reassemble & reinstall. At the same time the radiator group would be disassembled and cleaned which of course would include the aircon condenser. As stated above the dryer would be replaced and (if applicable) the accumulator. Filters are 293-1184 & 185-8154. We used to change both every 250 operating hours. Some may consider it overkill but it's what we did.
I want to buy a used machine from you Nige.....lol Stuff like this does not bother me quite as bad knowing it has never been into. I HATE working on bastardized equipment where I could count the previous "tech"s brain cells on one hand.
No you wouldn't. It would have at least 40k hours on it and been ridden hard all its life. The one thing it will be though is maintained half-way decent. The problem in 24/7 operations is that operators in general take no responsibility for their machines other than pulling levers (and moaning if the A/C isn't cold enough or a worklight is out) therefore the maintenance dept has to do it for them. Cabs are generally like a pig sty, hence what you have to do to keep the A/C working. Based on what you've described I would say you are probably in for all I listed above, if not immediately then in the very near future.
Alrighty. So evap is clean and I will need to grab a condenser before I go much further. Thoughts where I can obtain one aftermarket? I'd go back to cat but not too impressed with this one. Also, I was able to get the vent selector mechanism going again but sort of. The actuator was loaded with crap but gears were all fine. It works but IMO, it os not delivering the torque that it should OR the mechanism is not free enough? Just how free should it be? I can pretty much select with my fingers on the drive shaft but I would not say it is "easy". There are a couple hard points. I blew everything off/out and silicone sprayed everything. It was most certainly frozen up. The decision now is whether a new actuator is the right direction or work harder on the mechanism? Not real sure what else I can do though. It is a little hokey!
How was you testing if the condenser was bad? I put the number into my Googalator, and the whole first page lists vendors, both OEM and aftermarket.
It seems the condenser holds gas somewhat until you run it and I think the heat and pressure help it leak. The UV detector was very telling. I ran it some but I know she is probably down about 50%.
Gents, the new condenser is here so figured I would throw it in. However, I realized I did not determine which refrigerant oil this system uses? Could anyone possibly check procedure for the condenser? I generally drain out what oil I can from the cooler as a baseline and if I get no oil, I don't add any. There are a few different oils for 134A so I need to get that right if I have to add. OH, Heymccall, you were 100% right on the T30 for the plastic behind the seat. Have no idea how I read T60....
Should be PAG oil in that system.
There is PAG 46, 100, and 150. They are compatible with each other but like to ensure the right oil. Bet that compressor ain't cheap.
PAG 100 is the oil listed for that system with R134a refrigerant. You may find the table below useful.
Thank you sir!
Thanks for the help guys. I think we have this one wrapped with a bow. Most of the cooling issue was air/water in the system. I took my vac down to well below 500 microns and took hours to get that system dry. New condenser is leak free and vent temps are 20* colder. I won't want to get out of it!
Ideal vent temp with the system on max, high fan, on recirc is 35-45 degrees. If your in that range you should be good.
I tested initially at 47* but the cab is not sealed very good right now and it is insane hot here right now! We will get in the 80s tomorrow so I intend to run a vent test then just to make sure.