AC not cold enough, compressor cycling a lot

[RenoHuskerDu]

Howdy guys, I have a 2019 XR4155 with less than 500 hours on it. The AC and coolant radiators are clean. I don't work with hay or dusty aggregates.

Now that it's HOT in Texas, my AC is insufficient to work during the hot hours. It's 0930 now and I just came in after backdragging a gravel path. Too hot already. My nearest dealer is now over 2 hours away (another story) and they informed me that the AC is out of warranty.

Both high side and low side have acceptable values ... when the compressor runs. But then it stops frequently and low side climbs up in pressure quickly. I heard that this issue was discussed in the Fakebook LS Owners group, but good luck using Fakebook search, it is useless. A couple guys on FB said they had similar issues and the dealer cleaned the condenser and replaced the expansion valve, which fixed it. My dealer was John Ryan (RIP) of RCO and he gave me air and water cleaning tools with the tractor for the radiators.

I could jumper the compressor and see if high and low sides stay in the correct range. In this heat I should have 40 and 250 psi. Roughly. The problem could be a malfunctioning high pressure switch. But the way the high and low converge so quickly worries me. Shouldn't the compressor seals make that a slow process? The gauges start moving right away as soon as the compressor stops.

So I'm wondering if any of you had similar issues. I don't much like expansion valve systems. An orifice tube is much simpler and reliable. But there it is.

 

[Torvy]

Not sure where you are at, but I was looking around RCO when I was shopping (Greenville). There's a dealer in Tyler and another in Azle that I know of. The guy in Azle seemed to be a bit more 'together ', but both were nice people. Azle was just too far from our place in East Texas.

I feel you with the heat. One reason I got open station is AC is great until it is not. Cab magnifies the heat. This time of year, all outdoor work stops at 10am. I'm an early riser, so that gives me 4-5 hours if needed.

Good luck finding a solution. I'm sure someone here knows what to do to fix it.

 

[5030]

Short cycling is indicative of a couple things, insufficient refrigerant, a failing superheat relay (which can be mounted on the dryer) or a leaking blend valve (which controls the flow of heated coolant to the heater HX during cold weather. Been my experience that every blend valve leaks somewhat and to that end, I installed a ball valve on one of the heated coolant lines to shut off the flow during the summer months.

 

[ssgp2]

The pressures will change (converge) very quickly when the compressor stops. Short cycling can be caused by a few things. Most common is low charge, but that doesn't seem to be the case here. Some low pressure switches are adjustable (usually a small set screw between the male electrical connectors on the switch) and this could cause your symptoms if not properly set. This type of LP switch is very useful when/if changing refrigerant types. Faulty HP or LP switches are not uncommon. An intermittent blockage at the metering device, fixed orifice or TEV can cause this problem. By-passing each switch individually will help isolate the issue. First, insure that both condenser coils and evaporator coils are CLEAN.
After 25+ years in the HVAC industry, I've never heard of a "superheat relay" Good luck

 

[Cycledude]

Short cycling is indicative of a couple things, insufficient refrigerant, a failing superheat relay (which can be mounted on the dryer) or a leaking blend valve (which controls the flow of heated coolant to the heater HX during cold weather. Been my experience that every blend valve leaks somewhat and to that end, I installed a ball valve on one of the heated coolant lines to shut off the flow during the summer months.

yes being able to turn off the hot water can make a major difference with the air conditioning ! Years ago when I was driving semi trucks over the road I often turned the hot water off in hot weather.

 

[5030]

My Western Star (yes, I still own a Class 8 tractor) comes from the factory with shutoff valves. problem is, tractors don't but it's an easy modification anyway.

Like I said, never seen a blend valve that didn't leak.

 

[Harry in Ky]

Check your PM inbox

 

[RenoHuskerDu]

Thank you gentlemen who replied. I must eat crow now. I used the cleaning tools on the various radiators last week. First I used compressed air and my 90 degree cleaning nozzle. Lots of dust.

Then I went to the 90 degree water jet wand. Lots of mud. I had no idea so much had accumulated. If only John Ryan of RCO were still with us, I'm sure he would have advised me quickly on what to do.

After all that, the AC runs much cooler. I don't believe that I have a mechanical or electronic problem after all.

Yummy crow ! At least it's meat and not some soy bug nwo poison.

 

[Torvy]

Maybe Hard 8 will smoke it for you. If not, get some jalapeños to make it better.

 

[jaxs]

Eating crow isn't called for,it's acceptable to ask questions on the web before doing any troubleshooting. It's near requisite to say routine cleaning and maintenance is up to date just to find if anyone sees through the false statements.