Im hoping someone has been down this road before with 631G prefix CLR, customer has a few of these buggies and they love to leak all the refrigerant out when its -40 over winter. I pressure test, vacuum, oil and fill them in the spring and generally they are good. This year however its been endless issues.... Every time an operator says it fails by the time they get to me its working again, pressures are good, cab is chilling to 5 degrees (celsius) I run them for an hour with zero issues, they go back to work and same thing a couple hours later. I have had my thermal camera on the condenser to look for hotspots, tugged on wires around compressor and in evaporator box, had my gauges hooked up and tied to the machine driving around bouncing trying to get the ac to cut out. Checked for drains plugging freezing up although the cab fans have never cut out according to the operator. I am not super familiar with the compressor protection module but it appears to be working One buggy eventually popped a compressor so I replaced compressor, accumulator and receiver dryer and it has worked perfect. Anyone had similar issues and found a solution ? Im worried compressor are going to start failing and the parts cannon is going to have to get loaded. Thanks Calum
I have no knowledge of the 631 buy I am going to guess, stupidly,, the evaporator is freezing up and there is very little air flow. Ask the operators to turn off the AC button when it acts stupid and a couple of minutes or so later turn the compressor back on and see what happens. I assume you can turn the compressor off while leaving the fan running.
You mentioned that you had changed the dryer, I'm assuming as part of the repairs resulting from the compressor failure. Is there any programme of dryer replacement as a PM task.? The reason I ask is that in areas with relatively high humidity we replaced dryers on an annual basis in an attempt to prevent compressor and other system failures.
The difference between you testing and them running is that they are at full rpm most of the time. This drops the low side pressure more and can cause it to freeze up faster. I think the orifice tube or expansion valve is still in the dryer on these. I have seen a failing dryer plug or restrict the orifice which makes it freeze up at the dryer. Try replacing the dryer. I see there is a thermostatic switch on the evap core that will cut the ac out if the core gets too cold. I have seen these switches fail and cut out intermittently. You can jumper it for a test to see if it helps. The part number is 3e5464.
It is part of the dryer, although it is available as a separate part if necessary
Negative we have not been doing that but may have to start! I am assuming that is why CAT sell them with quick connectors on them though. Generally in Saskatchewan its not super humid bar a couple weeks in June and July. Were there any tell tale signs that compressor appeared to be failing if a dryer was missed on an annual replacement or would it just pop ?
Nope. They are like that so that the dryer can be replaced without having to de-gas the system, in other words to make it easier to carry out PM work. If you look at the Maintenance Interval Schedule it states that the aircon dryer replacement interval is "Every 1000 Service Hours or 6 Months". Maybe someone should start looking at the PM checklist and see what else is being missed.?
Yep that's what I meant so they can be changed easily, I think that interval is referring to the air brake dryer cartridge is it not ?
Yes you're right. My bad.