06E carlyle dual unloaderproper adjustments

[anthonyac1]

I have an 06E with 2 unloaders installed. This unit is a water cooled packaged unit DX straight cooling. There are 3 other units like this one. But this is the only compressor with 2 unloaders on one compressor. So my question is what is the best way and pressure rang to dial in the 2 unloaders? A Sr. Tech mentioned to set the 2nd unloader so it does not unload. Basically its installed but does not do anything. He figured its not really needed to have 2 unloaders. What are ya'lls opinions?

[crazzycajun]

Have you seen this thread post #3 has some good literature it’s in the pro section
https://hvac-talk.com/vbb/showthread.php?1177181

[71CHOPS]

I set them for saturated temperature. you'll have to play with them on your particular system, depending on your goal of longer run time vs. cycling, etc.

you don't want your coil to spend a lot of time below 32*, otherwise you'll have frost buildup. one may have to be set around 38-40*, and the other around 32-34*......it's really dependent on how your system operates. If it's a multi compressor unit, you also have to consider staging of the other compressors....usually the one with loaders is stage 1.

[Cool breeze 38]

being its an 06E im going to say its R22 right? Ill use r22 pressures as an example.

Basically you want the two unloading heads to be at separate set points. say unload at 59 psi and load up at 80 psi. the second unload at 66 psi and back in at 76 psi. Yes I have them cross to even run time between the cylinders. Or you could do 59-69 and 66-80. Water temp will determine the suction pressure. Its much easier with electronic then adjusting the nut and differential. I have seen them set as low as 55 psi with no issues. As for the pressures. I gave you basic numbers. But its best to adjust that unit to actual demands. Look at the water temp have one unload 2 deg from set point. and the other 4 deg from set point. Adjust the differential to the one unloading loads up 5 deg from set point and the other 8 deg from set point. Hope this gives you a decent idea on what to do. Use your knowledge of the unit and building to determine the best settings overall. You will never get this chiller to operate right at or close to set point. close yes but not dead on. You dont want to either. You should be adjusting the unloaders so it never shuts down, but cycles on the one unloaded. the second one would only run under high load.

[anthonyac1]

Have you seen this thread post #3 has some good literature it’s in the pro section
https://hvac-talk.com/vbb/showthread.php?1177181

I found that thread. I was reading the pdf’s. I still have more reading to do. I was looking for the easy answer lol. Thank you for the info.